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  • getting SIGSEGV in std::_List_const_iterator<Exiv2::Exifdatum>::operator++ whilst using jni

    - by HJED
    Hi I'm using jni to access the exiv2 API in my Java project and I'm getting a SIGSEGV error in std::_List_const_iterator::operator++. I'm uncertain how to fix this error. I've tried using high -Xmx values as well as running on both jdk1.6.0 (server and cacao JVMs) and 1.7.0 (server JVM). gdb traceback: #0 0x00007fffa36f2363 in std::_List_const_iterator<Exiv2::Exifdatum>::operator++ (this=0x7ffff7fd3500) at /usr/include/c++/4.4/bits/stl_list.h:223 #1 0x00007fffa36f2310 in std::__distance<std::_List_const_iterator<Exiv2::Exifdatum> > (__first=..., __last=...) at /usr/include/c++/4.4/bits/stl_iterator_base_funcs.h:79 #2 0x00007fffa36f224d in std::distance<std::_List_const_iterator<Exiv2::Exifdatum> > (__first=..., __last=...) at /usr/include/c++/4.4/bits/stl_iterator_base_funcs.h:114 #3 0x00007fffa36f1f27 in std::list<Exiv2::Exifdatum, std::allocator<Exiv2::Exifdatum> >::size (this=0x7fffa4030910) at /usr/include/c++/4.4/bits/stl_list.h:805 #4 0x00007fffa36f1d50 in Exiv2::ExifData::count (this=0x7fffa4030910) at /usr/local/include/exiv2/exif.hpp:518 #5 0x00007fffa36f1d30 in Exiv2::ExifData::empty (this=0x7fffa4030910) at /usr/local/include/exiv2/exif.hpp:516 #6 0x00007fffa36f1763 in getVars (path=0x7fffa401d2f0 "/home/hjed/PC100001.JPG", env=0x6131c8, obj=0x7ffff7fd37a8) at src/main.cpp:146 #7 0x00007fffa36f19d8 in Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv (env=0x6131c8, obj=0x7ffff7fd37a8, path=0x7ffff7fd37a0, obj2=0x7ffff7fd3798) at src/main.cpp:160 #8 0x00007ffff21d9cc8 in ?? () #9 0x00000000fffffffe in ?? () #10 0x00007ffff7fd3740 in ?? () #11 0x0000000000613000 in ?? () #12 0x00007ffff7fd3738 in ?? () #13 0x00007fffaa1076e0 in ?? () #14 0x00007ffff7fd37a8 in ?? () #15 0x00007fffaa108d10 in ?? () #16 0x0000000000000000 in ?? () Java error: # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x00007fac11223363, pid=11905, tid=140378349111040 # # JRE version: 6.0_20-b20 # Java VM: OpenJDK 64-Bit Server VM (19.0-b09 mixed mode linux-amd64 ) # Derivative: IcedTea6 1.9.2 # Distribution: Ubuntu 10.10, package 6b20-1.9.2-0ubuntu2 # Problematic frame: # C [libExiff2-binding.so+0x4363] _ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0xf # # If you would like to submit a bug report, please include # instructions how to reproduce the bug and visit: # https://bugs.launchpad.net/ubuntu/+source/openjdk-6/ # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # --------------- T H R E A D --------------- Current thread (0x0000000000dbf000): JavaThread "main" [_thread_in_native, id=11909, stack(0x00007fac61920000,0x00007fac61a21000)] siginfo:si_signo=SIGSEGV: si_errno=0, si_code=128 (), si_addr=0x0000000000000000 Registers: ... Register to memory mapping: RAX=0x6c8948f0245c8948 0x6c8948f0245c8948 is pointing to unknown location RBX=0x00007fac0c042c00 0x00007fac0c042c00 is pointing to unknown location RCX=0x0000000000000000 0x0000000000000000 is pointing to unknown location RDX=0x6c8948f0245c8948 0x6c8948f0245c8948 is pointing to unknown location RSP=0x00007fac61a1f4e0 0x00007fac61a1f4e0 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE RBP=0x00007fac61a1f4e0 0x00007fac61a1f4e0 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE RSI=0x00007fac61a1f4f0 0x00007fac61a1f4f0 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE RDI=0x00007fac61a1f500 0x00007fac61a1f500 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R8 =0x00007fac0c054630 0x00007fac0c054630 is pointing to unknown location R9 =0x00007fac61a1f358 0x00007fac61a1f358 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R10=0x00007fac61a1f270 0x00007fac61a1f270 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R11=0x00007fac11223354 0x00007fac11223354: _ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0 in /home/hjed/libExiff2-binding.so at 0x00007fac1121f000 R12=0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R13=0x00007fac13ad1be8 {method} - klass: {other class} R14=0x00007fac61a1f7a8 0x00007fac61a1f7a8 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R15=0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE Top of Stack: (sp=0x00007fac61a1f4e0) ... Instructions: (pc=0x00007fac11223363) ... Stack: [0x00007fac61920000,0x00007fac61a21000], sp=0x00007fac61a1f4e0, free space=1021k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) C [libExiff2-binding.so+0x4363] _ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0xf C [libExiff2-binding.so+0x4310] _ZSt10__distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_St18input_iterator_tag+0x26 C [libExiff2-binding.so+0x424d] _ZSt8distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_+0x36 C [libExiff2-binding.so+0x3f27] _ZNKSt4listIN5Exiv29ExifdatumESaIS1_EE4sizeEv+0x33 C [libExiff2-binding.so+0x3d50] _ZNK5Exiv28ExifData5countEv+0x18 C [libExiff2-binding.so+0x3d30] _ZNK5Exiv28ExifData5emptyEv+0x18 C [libExiff2-binding.so+0x3763] _Z7getVarsPKcP7JNIEnv_P8_jobject+0x3e3 C [libExiff2-binding.so+0x39d8] Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv+0x4b j photo.exiv2.Exiv2MetaDataStore.impl_loadFromExiv(Ljava/lang/String;Lphoto/exiv2/Exiv2MetaDataStore;)V+0 j photo.exiv2.Exiv2MetaDataStore.loadFromExiv2()V+9 j photo.exiv2.Exiv2MetaDataStore.loadData()V+1 j photo.exiv2.Exiv2MetaDataStore.<init>(Lphoto/ImageFile;)V+10 j photo.ImageFile.<init>(Ljava/lang/String;)V+11 j test.Main.main([Ljava/lang/String;)V+67 v ~StubRoutines::call_stub V [libjvm.so+0x428698] V [libjvm.so+0x4275c8] V [libjvm.so+0x432943] V [libjvm.so+0x447f91] C [java+0x3495] JavaMain+0xd75 Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j photo.exiv2.Exiv2MetaDataStore.impl_loadFromExiv(Ljava/lang/String;Lphoto/exiv2/Exiv2MetaDataStore;)V+0 j photo.exiv2.Exiv2MetaDataStore.loadFromExiv2()V+9 j photo.exiv2.Exiv2MetaDataStore.loadData()V+1 j photo.exiv2.Exiv2MetaDataStore.<init>(Lphoto/ImageFile;)V+10 j photo.ImageFile.<init>(Ljava/lang/String;)V+11 j test.Main.main([Ljava/lang/String;)V+67 v ~StubRoutines::call_stub --------------- P R O C E S S --------------- Java Threads: ( => current thread ) 0x00007fac0c028000 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=11924, stack(0x00007fac11532000,0x00007fac11633000)] 0x00007fac0c025800 JavaThread "CompilerThread1" daemon [_thread_blocked, id=11923, stack(0x00007fac11633000,0x00007fac11734000)] 0x00007fac0c022000 JavaThread "CompilerThread0" daemon [_thread_blocked, id=11922, stack(0x00007fac11734000,0x00007fac11835000)] 0x00007fac0c01f800 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=11921, stack(0x00007fac11835000,0x00007fac11936000)] 0x00007fac0c001000 JavaThread "Finalizer" daemon [_thread_blocked, id=11920, stack(0x00007fac11e2d000,0x00007fac11f2e000)] 0x0000000000e36000 JavaThread "Reference Handler" daemon [_thread_blocked, id=11919, stack(0x00007fac11f2e000,0x00007fac1202f000)] =>0x0000000000dbf000 JavaThread "main" [_thread_in_native, id=11909, stack(0x00007fac61920000,0x00007fac61a21000)] Other Threads: 0x0000000000e2f800 VMThread [stack: 0x00007fac1202f000,0x00007fac12130000] [id=11918] 0x00007fac0c02b000 WatcherThread [stack: 0x00007fac11431000,0x00007fac11532000] [id=11925] ... Heap PSYoungGen total 18432K, used 632K [0x00007fac47210000, 0x00007fac486a0000, 0x00007fac5bc10000) eden space 15808K, 4% used [0x00007fac47210000,0x00007fac472ae188,0x00007fac48180000) from space 2624K, 0% used [0x00007fac48410000,0x00007fac48410000,0x00007fac486a0000) to space 2624K, 0% used [0x00007fac48180000,0x00007fac48180000,0x00007fac48410000) PSOldGen total 42240K, used 0K [0x00007fac1de10000, 0x00007fac20750000, 0x00007fac47210000) object space 42240K, 0% used [0x00007fac1de10000,0x00007fac1de10000,0x00007fac20750000) PSPermGen total 21248K, used 2831K [0x00007fac13810000, 0x00007fac14cd0000, 0x00007fac1de10000) object space 21248K, 13% used [0x00007fac13810000,0x00007fac13ad3d80,0x00007fac14cd0000) Dynamic libraries: ... VM Arguments: jvm_args: -Dfile.encoding=UTF-8 java_command: test.Main Launcher Type: SUN_STANDARD Environment Variables: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games USERNAME=hjed LD_LIBRARY_PATH=/usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server:/usr/lib/jvm/java-6-openjdk/jre/lib/amd64:/usr/lib/jvm/java-6-openjdk/jre/../lib/amd64 SHELL=/bin/bash DISPLAY=:0.0 Signal Handlers: ... --------------- S Y S T E M --------------- OS:Ubuntu 10.10 (maverick) uname:Linux 2.6.35-24-generic #42-Ubuntu SMP Thu Dec 2 02:41:37 UTC 2010 x86_64 libc:glibc 2.12.1 NPTL 2.12.1 rlimit: STACK 8192k, CORE 0k, NPROC infinity, NOFILE 1024, AS infinity load average:0.27 0.31 0.30 /proc/meminfo: MemTotal: 4048200 kB MemFree: 106552 kB Buffers: 838212 kB Cached: 1172496 kB SwapCached: 0 kB Active: 1801316 kB Inactive: 1774880 kB Active(anon): 1224708 kB Inactive(anon): 355012 kB Active(file): 576608 kB Inactive(file): 1419868 kB Unevictable: 64 kB Mlocked: 64 kB SwapTotal: 7065596 kB SwapFree: 7065596 kB Dirty: 20 kB Writeback: 0 kB AnonPages: 1565608 kB Mapped: 213424 kB Shmem: 14216 kB Slab: 164812 kB SReclaimable: 102576 kB SUnreclaim: 62236 kB KernelStack: 4784 kB PageTables: 44908 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 9089696 kB Committed_AS: 3676872 kB VmallocTotal: 34359738367 kB VmallocUsed: 332952 kB VmallocChunk: 34359397884 kB HardwareCorrupted: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 48704 kB DirectMap2M: 4136960 kB CPU:total 8 (4 cores per cpu, 2 threads per core) family 6 model 26 stepping 5, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1, sse4.2, popcnt, ht Memory: 4k page, physical 4048200k(106552k free), swap 7065596k(7065596k free) vm_info: OpenJDK 64-Bit Server VM (19.0-b09) for linux-amd64 JRE (1.6.0_20-b20), built on Dec 10 2010 19:45:55 by "buildd" with gcc 4.4.5 main.cpp: jobject toJava(std::auto_ptr<Exiv2::Value> v, const char * type, JNIEnv * env) { jclass stringClass; jmethodID cid; jobject result; stringClass = env->FindClass("photo/exiv2/Value"); cid = env->GetMethodID(stringClass, "<init>", "(Ljava/lang/String;Ljava/lang/Object;)V"); jvalue val; if ((strcmp(type, "String") == 0) || (strcmp(type, "String") == 0)) { val.l = env->NewStringUTF(v->toString().c_str()); } else if (strcmp(type, "Short") == 0) { val.s = v->toLong(0); } else if (strcmp(type, "Long") == 0) { val.j = v->toLong(0); } result = env->NewObject(stringClass, cid, env->NewStringUTF(v->toString().c_str()), val); return result; } void inLoop(std::auto_ptr<MetadataContainer> md, JNIEnv * env, jmethodID mid, jobject obj) { jvalue values[2]; const char* key = md->key().c_str(); values[0].l = env->NewStringUTF(key); /** md->value().toString().c_str(); const char* value = md->typeName(); values[1].l = env->NewStringUTF(value); TODO: do type conversions */ //std::cout << md->typeName() << std::endl; /** const char* type = md->value().toString().c_str(); values[1].l = env->NewStringUTF(type);*/ values[1].l = toJava(md->getValue(), md->typeName(), env); env->CallVoidMethodA(obj, mid, values); } void getVars(const char* path, JNIEnv * env, jobject obj) { //Load image Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(path); assert(image.get() != 0); image->readMetadata(); //load method jclass cls = env->GetObjectClass(obj); jmethodID mid = env->GetMethodID(cls, "exiv2_reciveElement", "(Ljava/lang/String;Lphoto/exiv2/Value;)V"); //Load IPTC data /**loadIPTC(image, path, env, obj, mid); loadEXIF(image, path, env, obj, mid);*/ Exiv2::IptcData &iptcData = image->iptcData(); if (mid != NULL) { //is there any IPTC data AND check that method exists if (iptcData.empty()) { std::string error(path); error += ": failed loading IPTC data, there may not be any data"; } else { Exiv2::IptcData::iterator end = iptcData.end(); for (Exiv2::IptcData::iterator md = iptcData.begin(); md != end; ++md) { std::auto_ptr<MetadataContainer> meta(new MetadataContainer(md)); inLoop(meta, env, mid, obj); } } Exiv2::ExifData &exifData = image->exifData(); //is there any Exif data AND check that method exists if (exifData.empty()) { //error occurs here (main.cpp:146) std::string error(path); error += ": failed loading Exif data, there may not be any data"; } else { Exiv2::ExifData::iterator end = exifData.end(); for (Exiv2::ExifData::iterator md = exifData.begin(); md != end; ++md) { std::auto_ptr<MetadataContainer> meta(new MetadataContainer(md)); inLoop(meta, env, mid, obj); } } } else { std::string error(path); error += ": failed to load method"; } } JNIEXPORT void JNICALL Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv(JNIEnv * env, jobject obj, jstring path, jobject obj2) { const char* path2 = env->GetStringUTFChars(path, NULL); getVars(path2, env, obj); env->ReleaseStringUTFChars(path, path2); } Thanks for any help, HJED EDIT This is the output when runing the jvm with the -cacao option: run: null:/usr/local/lib Error: Directory Olympus2 with 1536 entries considered invalid; not read. LOG: [0x00007ff005376700] We received a SIGSEGV and tried to handle it, but we were LOG: [0x00007ff005376700] unable to find a Java method at: LOG: [0x00007ff005376700] LOG: [0x00007ff005376700] PC=0x00007feffe4ee67d LOG: [0x00007ff005376700] LOG: [0x00007ff005376700] Dumping the current stacktrace: at photo.exiv2.Exiv2MetaDataStore.impl_loadFromExiv(Ljava/lang/String;Lphoto/exiv2/Exiv2MetaDataStore;)V(Native Method) at photo.exiv2.Exiv2MetaDataStore.loadFromExiv2()V(Exiv2MetaDataStore.java:38) at photo.exiv2.Exiv2MetaDataStore.loadData()V(Exiv2MetaDataStore.java:29) at photo.exiv2.MetaDataStore.<init>(Lphoto/ImageFile;)V(MetaDataStore.java:33) at photo.exiv2.Exiv2MetaDataStore.<init>(Lphoto/ImageFile;)V(Exiv2MetaDataStore.java:20) at photo.ImageFile.<init>(Ljava/lang/String;)V(ImageFile.java:22) at test.Main.main([Ljava/lang/String;)V(Main.java:28) LOG: [0x00007ff005376700] vm_abort: WARNING, port me to C++ and use os::abort() instead. LOG: [0x00007ff005376700] Exiting... LOG: [0x00007ff005376700] Backtrace (15 stack frames): LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x4ff54) [0x7ff004306f54] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x5ac01) [0x7ff004311c01] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x66e9a) [0x7ff00431de9a] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x76408) [0x7ff00432d408] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x79a4c) [0x7ff004330a4c] LOG: [0x00007ff005376700] /lib/libpthread.so.0(+0xfb40) [0x7ff004d53b40] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0xf) [0x7feffe4ee67d] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZSt10__distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_St18input_iterator_tag+0x26) [0x7feffe4ee62a] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZSt8distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_+0x36) [0x7feffe4ee567] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNKSt4listIN5Exiv29ExifdatumESaIS1_EE4sizeEv+0x33) [0x7feffe4ee22b] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNK5Exiv28ExifData5countEv+0x18) [0x7feffe4ee054] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNK5Exiv28ExifData5emptyEv+0x18) [0x7feffe4ee034] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_Z7getVarsPKcP7JNIEnv_P8_jobject+0x3d7) [0x7feffe4ed947] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv+0x4b) [0x7feffe4edcdc] LOG: [0x00007ff005376700] [0x7feffe701ccd] Java Result: 134 BUILD SUCCESSFUL (total time: 0 seconds)

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  • C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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  • Win7 Bluescreen: IRQ_NOT_LESS_OR_EQUAL | athrxusb.sys

    - by wretrOvian
    Hi I'd left my system on last night, and found the bluescreen in the morning. This has been happening occasionally, over the past few days. Details: ================================================== Dump File : 022710-18236-01.dmp Crash Time : 2/27/2010 8:46:44 AM Bug Check String : DRIVER_IRQL_NOT_LESS_OR_EQUAL Bug Check Code : 0x000000d1 Parameter 1 : 00000000`00001001 Parameter 2 : 00000000`00000002 Parameter 3 : 00000000`00000000 Parameter 4 : fffff880`06b5c0e1 Caused By Driver : athrxusb.sys Caused By Address : athrxusb.sys+760e1 File Description : Product Name : Company : File Version : Processor : x64 Computer Name : Full Path : C:\Windows\minidump\022710-18236-01.dmp Processors Count : 2 Major Version : 15 Minor Version : 7600 ================================================== HiJackThis ("[...]" indicates removed text; full log posted to pastebin): Logfile of Trend Micro HijackThis v2.0.2 Scan saved at 8:49:15 AM, on 2/27/2010 Platform: Unknown Windows (WinNT 6.01.3504) MSIE: Internet Explorer v8.00 (8.00.7600.16385) Boot mode: Normal Running processes: C:\Windows\DAODx.exe C:\Program Files (x86)\ASUS\EPU\EPU.exe C:\Program Files\ASUS\TurboV\TurboV.exe C:\Program Files (x86)\PowerISO\PWRISOVM.EXE C:\Program Files (x86)\OpenOffice.org 3\program\soffice.exe C:\Program Files (x86)\OpenOffice.org 3\program\soffice.bin D:\Downloads\HijackThis.exe C:\Program Files (x86)\uTorrent\uTorrent.exe R1 - HKCU\Software\Microsoft\Internet Explorer\[...] [...] O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files (x86)\Java\jre6\bin\jp2ssv.dll O4 - HKLM\..\Run: [HDAudDeck] C:\Program Files (x86)\VIA\VIAudioi\VDeck\VDeck.exe -r O4 - HKLM\..\Run: [StartCCC] "C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe" MSRun O4 - HKLM\..\Run: [TurboV] "C:\Program Files\ASUS\TurboV\TurboV.exe" O4 - HKLM\..\Run: [PWRISOVM.EXE] C:\Program Files (x86)\PowerISO\PWRISOVM.EXE O4 - HKLM\..\Run: [googletalk] C:\Program Files (x86)\Google\Google Talk\googletalk.exe /autostart O4 - HKLM\..\Run: [AdobeCS4ServiceManager] "C:\Program Files (x86)\Common Files\Adobe\CS4ServiceManager\CS4ServiceManager.exe" -launchedbylogin O4 - HKCU\..\Run: [uTorrent] "C:\Program Files (x86)\uTorrent\uTorrent.exe" O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'LOCAL SERVICE') O4 - HKUS\S-1-5-19\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'LOCAL SERVICE') O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'NETWORK SERVICE') O4 - HKUS\S-1-5-20\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'NETWORK SERVICE') O4 - Startup: OpenOffice.org 3.1.lnk = C:\Program Files (x86)\OpenOffice.org 3\program\quickstart.exe O13 - Gopher Prefix: O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing) O23 - Service: AMD External Events Utility - Unknown owner - C:\Windows\system32\atiesrxx.exe (file missing) O23 - Service: ASUS System Control Service (AsSysCtrlService) - Unknown owner - C:\Program Files (x86)\ASUS\AsSysCtrlService\1.00.02\AsSysCtrlService.exe O23 - Service: DeviceVM Meta Data Export Service (DvmMDES) - DeviceVM - C:\ASUS.SYS\config\DVMExportService.exe O23 - Service: @%SystemRoot%\system32\efssvc.dll,-100 (EFS) - Unknown owner - C:\Windows\System32\lsass.exe (file missing) O23 - Service: ESET HTTP Server (EhttpSrv) - ESET - C:\Program Files\ESET\ESET NOD32 Antivirus\EHttpSrv.exe O23 - Service: ESET Service (ekrn) - ESET - C:\Program Files\ESET\ESET NOD32 Antivirus\x86\ekrn.exe O23 - Service: @%systemroot%\system32\fxsresm.dll,-118 (Fax) - Unknown owner - C:\Windows\system32\fxssvc.exe (file missing) O23 - Service: FLEXnet Licensing Service - Acresso Software Inc. - C:\Program Files (x86)\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe O23 - Service: FLEXnet Licensing Service 64 - Acresso Software Inc. - C:\Program Files\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService64.exe O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files (x86)\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe O23 - Service: @keyiso.dll,-100 (KeyIso) - Unknown owner - C:\Windows\system32\lsass.exe (file missing) O23 - Service: @comres.dll,-2797 (MSDTC) - Unknown owner - C:\Windows\System32\msdtc.exe (file missing) O23 - Service: @%SystemRoot%\System32\netlogon.dll,-102 (Netlogon) - Unknown owner - C:\Windows\system32\lsass.exe (file missing) O23 - Service: @%systemroot%\system32\psbase.dll,-300 (ProtectedStorage) - Unknown owner - C:\Windows\system32\lsass.exe (file missing) O23 - Service: Protexis Licensing V2 (PSI_SVC_2) - Protexis Inc. - c:\Program Files (x86)\Common Files\Protexis\License Service\PsiService_2.exe O23 - Service: @%systemroot%\system32\Locator.exe,-2 (RpcLocator) - Unknown owner - C:\Windows\system32\locator.exe (file missing) O23 - Service: @%SystemRoot%\system32\samsrv.dll,-1 (SamSs) - Unknown owner - C:\Windows\system32\lsass.exe (file missing) O23 - Service: @%SystemRoot%\system32\snmptrap.exe,-3 (SNMPTRAP) - Unknown owner - C:\Windows\System32\snmptrap.exe (file missing) O23 - Service: @%systemroot%\system32\spoolsv.exe,-1 (Spooler) - Unknown owner - C:\Windows\System32\spoolsv.exe (file missing) O23 - Service: @%SystemRoot%\system32\sppsvc.exe,-101 (sppsvc) - Unknown owner - C:\Windows\system32\sppsvc.exe (file missing) O23 - Service: Steam Client Service - Valve Corporation - C:\Program Files (x86)\Common Files\Steam\SteamService.exe O23 - Service: @%SystemRoot%\system32\ui0detect.exe,-101 (UI0Detect) - Unknown owner - C:\Windows\system32\UI0Detect.exe (file missing) O23 - Service: @%SystemRoot%\system32\vaultsvc.dll,-1003 (VaultSvc) - Unknown owner - C:\Windows\system32\lsass.exe (file missing) O23 - Service: @%SystemRoot%\system32\vds.exe,-100 (vds) - Unknown owner - C:\Windows\System32\vds.exe (file missing) O23 - Service: @%systemroot%\system32\vssvc.exe,-102 (VSS) - Unknown owner - C:\Windows\system32\vssvc.exe (file missing) O23 - Service: @%systemroot%\system32\wbengine.exe,-104 (wbengine) - Unknown owner - C:\Windows\system32\wbengine.exe (file missing) O23 - Service: @%Systemroot%\system32\wbem\wmiapsrv.exe,-110 (wmiApSrv) - Unknown owner - C:\Windows\system32\wbem\WmiApSrv.exe (file missing) O23 - Service: @%PROGRAMFILES%\Windows Media Player\wmpnetwk.exe,-101 (WMPNetworkSvc) - Unknown owner - C:\Program Files (x86)\Windows Media Player\wmpnetwk.exe (file missing) -- End of file - 6800 bytes CPU-Z ("[...]" indicates removed text; see full log posted to pastebin): CPU-Z TXT Report ------------------------------------------------------------------------- Binaries ------------------------------------------------------------------------- CPU-Z version 1.53.1 Processors ------------------------------------------------------------------------- Number of processors 1 Number of threads 2 APICs ------------------------------------------------------------------------- Processor 0 -- Core 0 -- Thread 0 0 -- Core 1 -- Thread 0 1 Processors Information ------------------------------------------------------------------------- Processor 1 ID = 0 Number of cores 2 (max 2) Number of threads 2 (max 2) Name AMD Phenom II X2 550 Codename Callisto Specification AMD Phenom(tm) II X2 550 Processor Package Socket AM3 (938) CPUID F.4.2 Extended CPUID 10.4 Brand ID 29 Core Stepping RB-C2 Technology 45 nm Core Speed 3110.7 MHz Multiplier x FSB 15.5 x 200.7 MHz HT Link speed 2006.9 MHz Instructions sets MMX (+), 3DNow! (+), SSE, SSE2, SSE3, SSE4A, x86-64, AMD-V L1 Data cache 2 x 64 KBytes, 2-way set associative, 64-byte line size L1 Instruction cache 2 x 64 KBytes, 2-way set associative, 64-byte line size L2 cache 2 x 512 KBytes, 16-way set associative, 64-byte line size L3 cache 6 MBytes, 48-way set associative, 64-byte line size FID/VID Control yes Min FID 4.0x P-State FID 0xF - VID 0x10 P-State FID 0x8 - VID 0x18 P-State FID 0x3 - VID 0x20 P-State FID 0x100 - VID 0x2C Package Type 0x1 Model 50 String 1 0x7 String 2 0x6 Page 0x0 TDP Limit 79 Watts TDC Limit 66 Amps Attached device PCI device at bus 0, device 24, function 0 Attached device PCI device at bus 0, device 24, function 1 Attached device PCI device at bus 0, device 24, function 2 Attached device PCI device at bus 0, device 24, function 3 Attached device PCI device at bus 0, device 24, function 4 Thread dumps ------------------------------------------------------------------------- CPU Thread 0 APIC ID 0 Topology Processor ID 0, Core ID 0, Thread ID 0 Type 0200400Ah Max CPUID level 00000005h Max CPUID ext. level 8000001Bh Cache descriptor Level 1, I, 64 KB, 1 thread(s) Cache descriptor Level 1, D, 64 KB, 1 thread(s) Cache descriptor Level 2, U, 512 KB, 1 thread(s) Cache descriptor Level 3, U, 6 MB, 2 thread(s) CPUID 0x00000000 0x00000005 0x68747541 0x444D4163 0x69746E65 0x00000001 0x00100F42 0x00020800 0x00802009 0x178BFBFF 0x00000002 0x00000000 0x00000000 0x00000000 0x00000000 0x00000003 0x00000000 0x00000000 0x00000000 0x00000000 0x00000004 0x00000000 0x00000000 0x00000000 0x00000000 0x00000005 0x00000040 0x00000040 0x00000003 0x00000000 [...] CPU Thread 1 APIC ID 1 Topology Processor ID 0, Core ID 1, Thread ID 0 Type 0200400Ah Max CPUID level 00000005h Max CPUID ext. level 8000001Bh Cache descriptor Level 1, I, 64 KB, 1 thread(s) Cache descriptor Level 1, D, 64 KB, 1 thread(s) Cache descriptor Level 2, U, 512 KB, 1 thread(s) Cache descriptor Level 3, U, 6 MB, 2 thread(s) CPUID 0x00000000 0x00000005 0x68747541 0x444D4163 0x69746E65 0x00000001 0x00100F42 0x01020800 0x00802009 0x178BFBFF 0x00000002 0x00000000 0x00000000 0x00000000 0x00000000 0x00000003 0x00000000 0x00000000 0x00000000 0x00000000 0x00000004 0x00000000 0x00000000 0x00000000 0x00000000 0x00000005 0x00000040 0x00000040 0x00000003 0x00000000 [...] Chipset ------------------------------------------------------------------------- Northbridge AMD 790GX rev. 00 Southbridge ATI SB750 rev. 00 Memory Type DDR3 Memory Size 4096 MBytes Channels Dual, (Unganged) Memory Frequency 669.0 MHz (3:10) CAS# latency (CL) 9.0 RAS# to CAS# delay (tRCD) 9 RAS# Precharge (tRP) 9 Cycle Time (tRAS) 24 Bank Cycle Time (tRC) 33 Command Rate (CR) 1T Uncore Frequency 2006.9 MHz Memory SPD ------------------------------------------------------------------------- DIMM # 1 SMBus address 0x50 Memory type DDR3 Module format UDIMM Manufacturer (ID) G.Skill (7F7F7F7FCD000000) Size 2048 MBytes Max bandwidth PC3-10700 (667 MHz) Part number F3-10600CL9-2GBNT Number of banks 8 Nominal Voltage 1.50 Volts EPP no XMP no JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency JEDEC #1 6.0-6-6-17-23 @ 457 MHz JEDEC #2 7.0-7-7-20-27 @ 533 MHz JEDEC #3 8.0-8-8-22-31 @ 609 MHz JEDEC #4 9.0-9-9-25-34 @ 685 MHz DIMM # 2 SMBus address 0x51 Memory type DDR3 Module format UDIMM Manufacturer (ID) G.Skill (7F7F7F7FCD000000) Size 2048 MBytes Max bandwidth PC3-10700 (667 MHz) Part number F3-10600CL9-2GBNT Number of banks 8 Nominal Voltage 1.50 Volts EPP no XMP no JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency JEDEC #1 6.0-6-6-17-23 @ 457 MHz JEDEC #2 7.0-7-7-20-27 @ 533 MHz JEDEC #3 8.0-8-8-22-31 @ 609 MHz JEDEC #4 9.0-9-9-25-34 @ 685 MHz DIMM # 1 SPD registers [...] DIMM # 2 SPD registers [...] Monitoring ------------------------------------------------------------------------- Mainboard Model M4A78T-E (0x000001F7 - 0x00A955E4) LPCIO ------------------------------------------------------------------------- LPCIO Vendor ITE LPCIO Model IT8720 LPCIO Vendor ID 0x90 LPCIO Chip ID 0x8720 LPCIO Revision ID 0x2 Config Mode I/O address 0x2E Config Mode LDN 0x4 Config Mode registers [...] Register space LPC, base address = 0x0290 Hardware Monitors ------------------------------------------------------------------------- Hardware monitor ITE IT87 Voltage 1 1.62 Volts [0x65] (VIN1) Voltage 2 1.15 Volts [0x48] (CPU VCORE) Voltage 3 5.03 Volts [0xBB] (+5V) Voltage 8 3.34 Volts [0xD1] (VBAT) Temperature 0 39°C (102°F) [0x27] (TMPIN0) Temperature 1 43°C (109°F) [0x2B] (TMPIN1) Fan 0 3096 RPM [0xDA] (FANIN0) Register space LPC, base address = 0x0290 [...] Hardware monitor AMD SB6xx/7xx Voltage 0 1.37 Volts [0x1D2] (CPU VCore) Voltage 1 3.50 Volts [0x27B] (CPU IO) Voltage 2 12.68 Volts [0x282] (+12V) Hardware monitor AMD Phenom II X2 550 Power 0 89.10 W (Processor) Temperature 0 35°C (94°F) [0x115] (Core #0) Temperature 1 35°C (94°F) [0x115] (Core #1)

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  • apt sources.list disabled on upgrade to 12.04

    - by user101089
    After a do-release-upgrade, I'm now running ubuntu 12.04 LTS, as indicated below > lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04 LTS Release: 12.04 Codename: precise However, I find that all the entries in my /etc/apt/sources.list were commented out except for one. QUESTION: Is it safe for me to edit these, replacing the old 'lucid' with 'precise' in what is shown below? ## unixteam source list # deb http://debian.yorku.ca/ubuntu/ precise main main/debian-installer restricted restricted/debian-installer # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu/ precise main restricted # disabled on upgrade to precise # deb http://debian.yorku.ca/ubuntu/ lucid-updates main restricted # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu/ lucid-updates main restricted # disabled on upgrade to precise # deb http://debian.yorku.ca/ubuntu/ precise universe # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu/ precise universe # disabled on upgrade to precise # deb http://debian.yorku.ca/ubuntu/ precise multiverse # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu/ precise multiverse # disabled on upgrade to precise # deb http://debian.yorku.ca/ubuntu lucid-security main restricted # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu lucid-security main restricted # disabled on upgrade to precise # deb http://debian.yorku.ca/ubuntu lucid-security universe # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu lucid-security universe # disabled on upgrade to precise # deb http://debian.yorku.ca/ubuntu lucid-security multiverse # disabled on upgrade to precise # deb-src http://debian.yorku.ca/ubuntu lucid-security multiverse # disabled on upgrade to precise # R sources # see http://cran.us.r-project.org/bin/linux/ubuntu/ for details # deb http://probability.ca/cran/bin/linux/ubuntu lucid/ # disabled on upgrade to precise deb http://archive.ubuntu.com/ubuntu precise main multiverse universe

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  • Make backup image (.tib/.vhd) as my main operating system?

    - by Joann
    My old hard drive is dying so I want to move my Windows 7 operating system to another hard drive. They say cloning using Acronis would do the trick, but for some reason it refuses to work. I also tried EASEUS Todo Backup, but it doesn't work either. Can you recommend some suggestions on how to transfer my operating system? I heard about converting .tib to .vhd and then booting from it, but does that achieve the same effect as cloning?

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  • C#/.NET Little Wonders: The ConcurrentDictionary

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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  • Why would my HDD main partition suddenly become hidden?

    - by Luis Oscar
    A few days ago I was using my computer as usual and I turned it off. The next day it wouldn't boot up. It just stayed after the hardware diagnostic window on the intermittent underscore screen. So clearly It wasn't booting up. I tried turning it on and off a couple of times with no avail. Finally I used windows 7 disk and it seemed as if there was no HDD. not even the installation would see the HDD. So i thought it was dead, i bought a new one installed it with windows and used a external case with the old HDD. plug it in and still couldn't see it. I finally downloaded a partition program EASUS or something and my HDD was there listed WITHOUT a system letter. I could however explore it and i set it as Unhidden and it came back to life. I could see it normally. I really just wish someone could explain to me what happened here, was it a virus? does it means the HDD is about to die? How can i prevent this or what should I do now? should i stop using this OLD HDD? Thanks

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  • Best practice with branching source code and application lifecycle

    - by Toni Frankola
    We are a small ISV shop and we usually ship a new version of our products every month. We use Subversion as our code repository and Visual Studio 2010 as our IDE. I am aware a lot of people are advocating Mercurial and other distributed source control systems but at this point I do not see how we could benefit from these, but I might be wrong. Our main problem is how to keep branches and main trunk in sync. Here is how we do things today: Release new version (automatically create a tag in Subversion) Continue working on the main trunk that will be released next month And the cycle repeats every month and works perfectly. The problem arises when an urgent service release needs to be released. We cannot release it from the main trunk (2) as it is under heavy development and it is not stable enough to be released urgently. In such case we do the following: Create a branch from the tag we created in step (1) Bug fix Test and release Push the change back to main trunk (if applicable) Our biggest problem is merging these two (branch with main). In most cases we cannot rely on automatic merging because e.g.: a lot of changes has been made to main trunk merging complex files (like Visual Studio XML files etc.) does not work very well another developer / team made changes you do not understand and you cannot just merge it So what you think is the best practice to keep these two different versions (branch and main) in sync. What do you do?

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  • How do I structure code and builds for continuous delivery of multiple applications in a small team?

    - by kingdango
    Background: 3-5 developers supporting (and building new) internal applications for a non-software company. We use TFS although I don't think that matters much for my question. I want to be able to develop a deployment pipeline and adopt continuous integration / deployment techniques. Here's what our source tree looks like right now. We use a single TFS Team Project. $/MAIN/src/ $/MAIN/src/ApplicationA/VSSOlution.sln $/MAIN/src/ApplicationA/ApplicationAProject1.csproj $/MAIN/src/ApplicationA/ApplicationAProject2.csproj $/MAIN/src/ApplicationB/... $/MAIN/src/ApplicationC $/MAIN/src/SharedInfrastructureA $/MAIN/src/SharedInfrastructureB My Goal (a pretty typical promotion pipeline) When a code change is made to a given application I want to be able to build that application and auto-deploy that change to a DEV server. I may also need to build dependencies on Shared Infrastructure Components. I often also have some database scripts or changes as well If developer testing passes I want to have an manually triggered but automated deploy of that build on a STAGING server where end-users will review new functionality. Once it's approved by end users I want to a manually triggered auto-deploy to production Question: How can I best adopt continuous deployment techniques in a multi-application environment? A lot of the advice I see is more single-application-specific, how is that best applied to multiple applications? For step 1, do I simply setup a separate Team Build for each application? What's the best approach to accomplishing steps 2 and 3 of promoting latest build to new environments? I've seen this work well with web apps but what about database changes

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  • Using INotifyPropertyChanged in background threads

    - by digitaldias
    Following up on a previous blog post where I exemplify databinding to objects, a reader was having some trouble with getting the UI to update. Here’s the rough UI: The idea is, when pressing Start, a background worker process starts ticking at the specified interval, then proceeds to increment the databound Elapsed value. The problem is that event propagation is limeted to current thread, meaning, you fire an event in one thread, then other threads of the same application will not catch it. The Code behind So, somewhere in my ViewModel, I have a corresponding bethod Start that initiates a background worker, for example: public void Start( ) { BackgroundWorker backgroundWorker = new BackgroundWorker( ); backgroundWorker.DoWork += IncrementTimerValue; backgroundWorker.RunWorkerAsync( ); } protected void IncrementTimerValue( object sender, DoWorkEventArgs e ) { do { if( this.ElapsedMs == 100 ) this.ElapsedMs = 0; else this.ElapsedMs++; }while( true ); } Assuming that there is a property: public int ElapsedMs { get { return _elapsedMs; } set { if( _elapsedMs == value ) return; _elapsedMs = value; NotifyThatPropertyChanged( "ElapsedMs" ); } } The above code will not work. If you step into this code in debug, you will find that INotifyPropertyChanged is called, but it does so in a different thread, and thus the UI never catches it, and does not update. One solution Knowing that the background thread updates the ElapsedMs member gives me a chance to activate BackgroundWorker class’ progress reporting mechanism to simply alert the main thread that something has happened, and that it is probably a good idea to refresh the ElapsedMs binding. public void Start( ) { BackgroundWorker backgroundWorker = new BackgroundWorker( ); backgroundWorker.DoWork += IncrementTimerValue; // Listen for progress report events backgroundWorker.WorkerReportsProgress = true; // Tell the UI that ElapsedMs needs to update backgroundWorker.RunWorkerCompleted += ( sender, e ) => { NotifyThatPropertyChanged( "ElapsedMs" ) }; backgroundWorker.RunWorkerAsync( ); } protected void IncrementTimerValue( object sender, DoWorkEventArgs e ) { do { if( this.ElapsedMs == 100 ) this.ElapsedMs = 0; else this.ElapsedMs++; // report any progress ( sender as BackgroundWorker ).ReportProgress( 0 ); }while( true ); } What happens above now is that I’ve used the BackgroundWorker cross thread mechanism to alert me of when it is ok for the UI to update it’s ElapsedMs field. Because the property itself is being updated in a different thread, I’m removing the NotifyThatPropertyChanged call from it’s Set method, and moving that responsability to the anonymous method that I created in the Start method. This is one way of solving the issue of having a background thread update your UI. I would be happy to hear of other cross-threading mechanisms for working in a MCP/MVC/MVVM pattern.

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  • Best practice with pyGTK and Builder XML files

    - by Phoenix87
    I usually design GUI with Glade, thus producing a series of Builder XML files (one such file for each application window). Now my idea is to define a class, e.g. MainWindow, that inherits from gtk.Window and that implements all the signal handlers for the application main window. The problem is that when I retrieve the main window from the containing XML file, it is returned as a gtk.Window instance. The solution I have adopted so far is the following: I have defined a class "Window" in the following way class Window(): def __init__(self, win_name): builder = gtk.Builder() self.builder = builder builder.add_from_file("%s.glade" % win_name) self.window = builder.get_object(win_name) builder.connect_signals(self) def run(self): return self.window.run() def show_all(self): return self.window.show_all() def destroy(self): return self.window.destroy() def child(self, name): return self.builder.get_object(name) In the actual application code I have then defined a new class, say MainWindow, that inherits frow Window, and that looks like class Main(Window): def __init__(self): Window.__init__(self, "main") ### Signal handlers ##################################################### def on_mnu_file_quit_activated(self, widget, data = None): ... The string "main" refers to the main window, called "main", which resides into the XML Builder file "main.glade" (this is a sort of convention I decided to adopt). So the question is: how can I inherit from gtk.Window directly, by defining, say, the class Foo(gtk.Window), and recast the return value of builder.get_object(win_name) to Foo?

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  • What are the main differences between SRV records and TXT records?

    - by Chris Adams
    Hi there, I'm trying to consolidate domain names for the servers I look after to just use one panel instead of 3 or 4, and one thing stopping me is that the provider I originally wanted to move them to only lets me the following kinds of records: A MX NS CNAME TXT The first four I understand, but I'm not sure about the relationship (if any) between SRV records and TXT records. Can I use TXT records in the place of SRV records? They both seem to be general text records to just point at a particular server without needing to specify a particular protocol, so it doesn't sound like a totally unreasonable assumption, but I'd rather check here before I break something. If I can only set the above records, does that mean I'm essentially unable to so any SRC record redirecting? Thanks!

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  • What is the main reason of adsl modem/routers dying ?

    - by ldigas
    The other day my home adsl modem/router (dwg 684t in this case) died. A guy from the telecom company came, brought another so no problem in day to day operation, but he also left this one. Now, I'm interested ... it didn't fall, it wasn't electrocuted ... but it just doesn't work. What could be the problem ? Can they be fixed ? Is it worth it (in which case I would have two which is always nice) ... What are the usual problems that occur with them ? In this case, I can connect to the router, I can see its settings, I just can't connect to the internet. With the new one everything works. Weird. Edit: Additional question: Can those things be fixed ? I mean, is it worth giving it to a local tinker for him to experiment on it ? I'm not looking for a definite opinion, just your personal advice ... (although in the end I think I'm gonna archive it in the "cylinder register")

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  • Unable to get to main screen and safe mode doesn't help.

    - by Link
    It is my friends computer so I am not very familiar with it, I am unable to get it to start. I can get to the logon screen but after entering the password there is an error (something to do with Roxio) and only the background loads. No Start menu, Taskbar or icons. If I boot it in safe mode it gets stuck on a black screen and don't even get the command prompt. I am confident that If I could get to the menu to edit startup programs then I could fix the problem... any Ideas?

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  • How to set up Asus RT-N66U in bridge mode with wired connection to main router?

    - by Milligan
    I have a wired router (TP-Link RT-860) in the basement where the cable service comes in. Eight wired ethernet connections span two buildings. I currently have a Linksys wireless router set up in bridge mode, but its signal doesn't span the whole area. I have purchased an Asus RT-N66U to replace it, but I can't figure out how to set it up in bridge mode. Does anyone know if this is possible? Second question: Would there be any advantage in installing DD-WRT on the Asus?

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  • C#.NET: How to update multiple .NET pages when a particular event occurs in one .Net page? In another words how to use Observer pattern(Publish and subscribe to events)

    Problem: Suppose you have a scenario in which you have to update multiple pages when an event occurs in main page. For example imagine you have a main page where you are dispalying a tab control. This tab control has 3 tab pages where you are loading 3 different user controls. On click of an update button in main page imagine if you have do something in all the 3 tab panels. In other words an event in main page has to be handled in many other pages. An event in main page which contains the tab control has to be handled in all the tab panels(user controls) Answer: Use Observer pattern Define a base page for the page that contains the tab control. Main page which contains the tab: Baseline_Baseline Basepage for the above main page: BaselineBasePage User control that has to be udpated for an event in main page: Baseline_PriorNonDeloitte Source Code: public class BaselineBasePage : System.Web.UI.Page { IList lstControls = new List(); public void Add(IObserver userControl) { lstControls.Add(userControl); } public void Remove(IObserver userControl) { lstControls.Remove(userControl); } public void RemoveAllUserControls() { lstControls.Clear(); } public void Update(SaveEventArgs e) { foreach (IObserver LobjControl in lstControls) { LobjControl.Save(e); } } } public interface IObserver { void Update(SaveEventArgs e); } public partial class Baseline_Baseline : BaselineBasePage { . . . this.Add(_ucPI); this.Add(_ucPI1); protected void abActionBar_saveClicked(object sender, EventArgs e) { SaveEventArgs se = new SaveEventArgs(); se.TabType = (BaselineTabType)tcBaseline.ActiveTabIndex; this.Update(se); } } Public class Baseline_PriorNonDeloitte : System.Web.UI.UserControl,IObserver { public void Update(SaveEventArgs e) { } } More info at: http://www.dofactory.com/Patterns/PatternObserver.aspx span.fullpost {display:none;}

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  • How to tell Linux to explicitly swap out main memory of a suspended process?

    - by Vi
    I run a memory-hungry process (mkcromfs) which consumes more memory than I have physical memory on my latop, so it is paging and swappin and thrashing all the time and loadavg is about 2 (compcache is already in use with usual swap partition as well), but slowly moving forward (Although I afraid it will finally try to allocate 2GB and crash draining 2 days of thrashing). When I want to use the laptop for something else, I stop the process, start X server, firefox and other programs. The problem is that when I start Firefox the loadavg jumps to 10 and the system becomes almost unresponsive at all (long time to turn on/off caps lock, slow mouse cursor position updates, slow switching from X server to Linux console, slow login). The stopped mkcromfs still holds a lot of memory (464.8 MiB and slowly falling) and moves it to swap only when more memory is needed for some other program, which results in a great slowdown. How to tell the Linux to swap out this process entirely (e.g. I'm not intending to resume it in short term), possibly waking from swap other data? Also it will be useful to be able to specify the exact swap device to swap the given process out.

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  • How to tell Linux to explicitly swap out main memory of suspended process?

    - by Vi
    I run a memory-hungry process (mkcromfs) which consumes more memory than I have physical memory on my latop, so it is paging and swappin and thrashing all the time and loadavg is about 2 (compcache is already in use with usual swap partition as well), but slowly moving forward (Although I afraid it will finally try to allocate 2GB and crash draining 2 days of thrashing). When I want to use the laptop for something else, I stop the process, start X server, firefox and other programs. The problem is that when I start Firefox the loadavg jumps to 10 and the system becomes almost unresponsive at all (long time to turn on/off caps lock, slow mouse cursor position updates, slow switching from X server to Linux console, slow login). The stopped mkcromfs still holds a lot of memory (464.8 MiB and slowly falling) and moves it to swap only when more memory is needed for some other program, which results in a great slowdown. How to tell the Linux to swap out this process entirely (e.g. I'm not intending to resume it in short term), possibly waking from swap other data? Also it will be useful to be able to specify the exact swap device to swap the given process out.

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  • What is the main reason for ADSL modem/routers dying?

    - by ldigas
    The other day my home ADSL modem/router (dwg 684t in this case) died. A guy from the telecom company came to my place and brought another one, but he also left this one. Now, I'm interested - it didn't fall, it wasn't electrocuted - but it just doesn't work. What could be the problem? Can it be fixed? Is it worth it (in which case I would have two which is always nice)? I'm not looking for a definite opinion, just your personal advice ... (although in the end I think I'm going to archive it in the "cylinder register") What are the usual problems that occur with them? In this case, I can connect to the router, I can see its settings, I just can't connect to the Internet. With the new one everything works. Weird.

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  • How do I set my main monitor to a higher resolution?

    - by Sean
    My laptop monitor's native resolution is 1280x800 and it just isnt big enough for me. I tried to set the resolution higher, but my graphics card only showed options upto 1280x800, and I figured that was the max res my card would allow. I found a monitor out on the street a few days ago and its native resolution is 1024x768. I have been playing around with it a bit. I was looking under the resolutions for it, and I can set it upto 1400x1050, so apparently my card allows for more than 1280x800, so why can't I set my laptop monitor to higher?

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  • Synergy 1.5 crash (OSX 10.6.8)

    - by Oliver
    THANKS FOR TAKING THE TIME TO READ THIS I recently installed Synergy 1.5 r2278 (for Mac OSX 10.6.8) and was using it fine for most of the day, then it decided to stop working (the only thing I changed systemwise was the screensaver - and then after it started crashing disabled it - to see if it would resolve). When I start Synergy (on the Mac - Client) it says: after about 5 seconds (and successfully connecting to the Server) "synergyc quit unexpectedly" Here is the crash log (w/ binery info removed - too long for post requirements) Process: synergyc [1026] Path: /Applications/Synergy.app/Contents/MacOS/synergyc Identifier: synergy Version: ??? (???) Code Type: X86 (Native) Parent Process: Synergy [1023] Date/Time: 2014-05-28 15:36:17.746 +0930 OS Version: Mac OS X 10.6.8 (10K549) Report Version: 6 Interval Since Last Report: 2144189 sec Crashes Since Last Report: 23 Per-App Interval Since Last Report: 10242 sec Per-App Crashes Since Last Report: 9 Anonymous UUID: 86D5A57C-13D4-470E-AC72-48ACDDDE5EB0 Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Crashed Thread: 5 Application Specific Information: abort() called Thread 0: Dispatch queue: com.apple.main-thread 0 libSystem.B.dylib 0x95cf3afa mach_msg_trap + 10 1 libSystem.B.dylib 0x95cf4267 mach_msg + 68 2 com.apple.CoreFoundation 0x95af02df __CFRunLoopRun + 2079 3 com.apple.CoreFoundation 0x95aef3c4 CFRunLoopRunSpecific + 452 4 com.apple.CoreFoundation 0x95aef1f1 CFRunLoopRunInMode + 97 5 com.apple.HIToolbox 0x93654e04 RunCurrentEventLoopInMode + 392 6 com.apple.HIToolbox 0x93654bb9 ReceiveNextEventCommon + 354 7 com.apple.HIToolbox 0x937dd137 ReceiveNextEvent + 83 8 synergyc 0x000356d0 COSXEventQueueBuffer::waitForEvent(double) + 48 9 synergyc 0x00010dd5 CEventQueue::getEvent(CEvent&, double) + 325 10 synergyc 0x00011fb0 CEventQueue::loop() + 272 11 synergyc 0x00044eb6 CClientApp::mainLoop() + 134 12 synergyc 0x0005c509 standardStartupStatic(int, char**) + 41 13 synergyc 0x000448a9 CClientApp::runInner(int, char**, ILogOutputter*, int (*)(int, char**)) + 137 14 synergyc 0x0005c4b0 CAppUtilUnix::run(int, char**) + 64 15 synergyc 0x000427df CApp::run(int, char**) + 63 16 synergyc 0x00006e65 main + 117 17 synergyc 0x00006dd9 start + 53 Thread 1: 0 libSystem.B.dylib 0x95d607da __sigwait + 10 1 libSystem.B.dylib 0x95d607b6 sigwait$UNIX2003 + 71 2 synergyc 0x00009583 CArchMultithreadPosix::threadSignalHandler(void*) + 67 3 libSystem.B.dylib 0x95d21259 _pthread_start + 345 4 libSystem.B.dylib 0x95d210de thread_start + 34 Thread 2: 0 libSystem.B.dylib 0x95d21aa2 __semwait_signal + 10 1 libSystem.B.dylib 0x95d2175e _pthread_cond_wait + 1191 2 libSystem.B.dylib 0x95d212b1 pthread_cond_timedwait$UNIX2003 + 72 3 synergyc 0x00009476 CArchMultithreadPosix::waitCondVar(CArchCondImpl*, CArchMutexImpl*, double) + 150 4 synergyc 0x0002b18f CCondVarBase::wait(double) const + 63 5 synergyc 0x0002ce68 CSocketMultiplexer::serviceThread(void*) + 136 6 synergyc 0x0002d698 TMethodJob<CSocketMultiplexer>::run() + 40 7 synergyc 0x0002b8f4 CThread::threadFunc(void*) + 132 8 synergyc 0x00008f30 CArchMultithreadPosix::doThreadFunc(CArchThreadImpl*) + 80 9 synergyc 0x0000902a CArchMultithreadPosix::threadFunc(void*) + 74 10 libSystem.B.dylib 0x95d21259 _pthread_start + 345 11 libSystem.B.dylib 0x95d210de thread_start + 34 Thread 3: Dispatch queue: com.apple.libdispatch-manager 0 libSystem.B.dylib 0x95d1a382 kevent + 10 1 libSystem.B.dylib 0x95d1aa9c _dispatch_mgr_invoke + 215 2 libSystem.B.dylib 0x95d19f59 _dispatch_queue_invoke + 163 3 libSystem.B.dylib 0x95d19cfe _dispatch_worker_thread2 + 240 4 libSystem.B.dylib 0x95d19781 _pthread_wqthread + 390 5 libSystem.B.dylib 0x95d195c6 start_wqthread + 30 Thread 4: 0 libSystem.B.dylib 0x95d19412 __workq_kernreturn + 10 1 libSystem.B.dylib 0x95d199a8 _pthread_wqthread + 941 2 libSystem.B.dylib 0x95d195c6 start_wqthread + 30 Thread 5 Crashed: 0 libSystem.B.dylib 0x95d610ee __semwait_signal_nocancel + 10 1 libSystem.B.dylib 0x95d60fd2 nanosleep$NOCANCEL$UNIX2003 + 166 2 libSystem.B.dylib 0x95ddbfb2 usleep$NOCANCEL$UNIX2003 + 61 3 libSystem.B.dylib 0x95dfd6f0 abort + 105 4 libSystem.B.dylib 0x95d79b1b _Unwind_Resume + 59 5 synergyc 0x00008fd1 CArchMultithreadPosix::doThreadFunc(CArchThreadImpl*) + 241 6 synergyc 0x0000902a CArchMultithreadPosix::threadFunc(void*) + 74 7 libSystem.B.dylib 0x95d21259 _pthread_start + 345 8 libSystem.B.dylib 0x95d210de thread_start + 34 Thread 5 crashed with X86 Thread State (32-bit): eax: 0x0000003c ebx: 0x95d60f39 ecx: 0xb0288a7c edx: 0x95d610ee edi: 0x00521950 esi: 0xb0288ad8 ebp: 0xb0288ab8 esp: 0xb0288a7c ss: 0x0000001f efl: 0x00000247 eip: 0x95d610ee cs: 0x00000007 ds: 0x0000001f es: 0x0000001f fs: 0x0000001f gs: 0x00000037 cr2: 0x002fe000 Model: MacBook2,1, BootROM MB21.00A5.B07, 2 processors, Intel Core 2 Duo, 2.16 GHz, 2 GB

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  • what is the main cause of 500 internal server error? [closed]

    - by Usman
    I want to know that I have hosted with a hosting company . My website gives "500 Internal server error many times" I have following Web server statistics :- Web Server Statistics Successful requests: 127,310 (7,504) Average successful requests per day: 814 (1,071) Successful requests for pages: 24,949 (1,309) Average successful requests for pages per day: 159 (186) Failed requests: 3,499 (58) Redirected requests: 10,091 (114) Distinct files requested: 5,791 (556) Distinct hosts served: 5,107 (330) Data transferred: 4.28 gigabytes (190.56 megabytes) Average data transferred per day: 28.03 megabytes (27.22 megabytes) Can you tell me my server condition by seeing this or i have to give another details. Thanks in advance

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  • C#.NET: How to update multiple .NET pages when a particular event occurs in one .Net page? In another words how to use Observer pattern(Publish and subscribe to events)

    Problem: Suppose you have a scenario in which you have to update multiple pages when an event occurs in main page. For example imagine you have a main page where you are dispalying a tab control. This tab control has 3 tab pages where you are loading 3 different user controls. On click of an update button in main page imagine if you have do something in all the 3 tab panels. In other words an event in main page has to be handled in many other pages. An event in main page which contains the tab control has to be handled in all the tab panels(user controls) Answer: Use Observer pattern Define a base page for the page that contains the tab control. Main page which contains the tab: Baseline_Baseline Basepage for the above main page: BaselineBasePage User control that has to be udpated for an event in main page: Baseline_PriorNonDeloitte Source Code: public class BaselineBasePage : System.Web.UI.Page { IList lstControls = new List(); public void Add(IObserver userControl) { lstControls.Add(userControl); } public void Remove(IObserver userControl) { lstControls.Remove(userControl); } public void RemoveAllUserControls() { lstControls.Clear(); } public void Update(SaveEventArgs e) { foreach (IObserver LobjControl in lstControls) { LobjControl.Save(e); } } } public interface IObserver { void Update(SaveEventArgs e); } public partial class Baseline_Baseline : BaselineBasePage { . . . this.Add(_ucPI); this.Add(_ucPI1); protected void abActionBar_saveClicked(object sender, EventArgs e) { SaveEventArgs se = new SaveEventArgs(); se.TabType = (BaselineTabType)tcBaseline.ActiveTabIndex; this.Update(se); } } Public class Baseline_PriorNonDeloitte : System.Web.UI.UserControl,IObserver { public void Update(SaveEventArgs e) { } } More info at: http://www.dofactory.com/Patterns/PatternObserver.aspx span.fullpost {display:none;}

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  • Why would delaying a thread response fix view corruption?

    - by Beth S
    6 times out of 10 my very simple iPhone app is getting a corrupted display on launch or crashes randomly. But it behaves fine in the simulator. The display corruption looks like mis-colored fonts, out of place font text, wrong background colors, etc. I've found a strange work-around.. when my thread delays by 2 seconds before calling the "done" notification, everything works swimmingly. The thread reads a web page and the "done" notification loads up a PickerView with strings. So what gives? Can I not safely initiate a threaded task from viewDidLoad? - (void) loadWebPage:(NSString *)urlAddition { NSAutoreleasePool *subPool = [[NSAutoreleasePool alloc] init]; NSString *pageSource; NSError *err; NSString *urlString = [NSString stringWithString:@"http://server/%@", urlAddition]; pageSource = [NSString stringWithContentsOfURL:[NSURL URLWithString: urlString] encoding:NSUTF8StringEncoding error:&err]; [NSThread sleepForTimeInterval:2.0]; // THIS STOPS THE DISPLAY CORRUPTION [[NSNotificationCenter defaultCenter] postNotificationName:@"webDoneNotification" object:nil]; [subPool drain]; } - (void) webDoneNotification: (NSNotification *)pNotification { [mediaArray release]; mediaArray = [[NSArray arrayWithObjects: [NSString stringWithString:@"new pickerview text"], nil] retain]; [mediaPickerView reloadAllComponents]; [mediaPickerView selectRow:0 inComponent:0 animated:NO]; } - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { mediaArray = [[NSArray arrayWithObjects: [NSString stringWithString:@"init pickerview text"], nil] retain]; if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { // Custom initialization } return self; } - (void)viewDidLoad { [super viewDidLoad]; myWebThread = [[WebThread alloc] initWithDelegate:self]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(webDoneNotification:) name:@"webDoneNotification" object:nil]; [myWebThread performSelectorInBackground:@selector(loadWebPage:) withObject:@""]; } Thanks! Update: Even a delay of 0.1 seconds is enough to completely fix the problem.

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  • What is an efficient strategy for multiple threads posting jobs and waiting for response from a single thread?

    - by jakewins
    In java, what is an efficient solution to the following problem: I have multiple threads (10-20 or so) generating jobs ("Job Creators"), and a single thread capable of performing them ("The worker"). Once a job creator has posted a job, it should wait for the job to finish, yielding no result other than "it's done", before it keeps going. For sending the jobs to the worker thread, I think a ring buffer or similar standard fan-in setup would perhaps be a good approach? But for a Job Creator to find out that her job has been done, I'm not so sure.. The job creators could sleep, and the worker interrupt them when done.. Or each job creator could have an atomic boolean that it checks, and that the worker sets. I dunno, neither of those feel very nice. I'd like to do it with as few (none, if possible) locks as absolutely possible. So to be clear: What I'm looking for is speed, not necessarily simplicity. Does anyone have any suggestions? Links to reading about concurrency strategies would also be very welcome!

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