Search Results

Search found 29101 results on 1165 pages for 'thread local storage'.

Page 210/1165 | < Previous Page | 206 207 208 209 210 211 212 213 214 215 216 217  | Next Page >

  • Is there performance to be gained by moving storage allocation local to a member function to its cla

    - by neuviemeporte
    Suppose I have the following C++ class: class Foo { double bar(double sth); }; double Foo::bar(double sth) { double a,b,c,d,e,f a = b = c = d = e = f = 0; /* do stuff with a..f and sth */ } The function bar() will be called millions of times in a loop. Obviously, each time it's called, the variables a..f have to be allocated. Will I gain any performance by making the variables a..f members of the Foo class and just initializing them at the function's point of entry? On the other hand, the values of a..f will be dereferenced through this-, so I'm wondering if it isn't actually a possible performance degradation. Is there any overhead to accessing a value through a pointer? Thanks!

    Read the article

  • What should i do for accomodating large scale data storage and retrieval?

    - by kailashbuki
    There's two columns in the table inside mysql database. First column contains the fingerprint while the second one contains the list of documents which have that fingerprint. It's much like an inverted index built by search engines. An instance of a record inside the table is shown below; 34 "doc1, doc2, doc45" The number of fingerprints is very large(can range up to trillions). There are basically following operations in the database: inserting/updating the record & retrieving the record accoring to the match in fingerprint. The table definition python snippet is: self.cursor.execute("CREATE TABLE IF NOT EXISTS `fingerprint` (fp BIGINT, documents TEXT)") And the snippet for insert/update operation is: if self.cursor.execute("UPDATE `fingerprint` SET documents=CONCAT(documents,%s) WHERE fp=%s",(","+newDocId, thisFP))== 0L: self.cursor.execute("INSERT INTO `fingerprint` VALUES (%s, %s)", (thisFP,newDocId)) The only bottleneck i have observed so far is the query time in mysql. My whole application is web based. So time is a critical factor. I have also thought of using cassandra but have less knowledge of it. Please suggest me a better way to tackle this problem.

    Read the article

  • Best ASP.NET Background Service Implementation

    - by Jason N. Gaylord
    What's the best implementation for more than one background service in an ASP.NET application? Timer Callback Timer timer = new Timer(new TimerCallback(MyWorkCallback), HttpContext, 5000, 5000); Thread or ThreadPool Thread thread = new Thread(Work); thread.IsBackground = true; thread.Start(); BackgroundWorker BackgroundWorker worker = new BackgroundWorker(); worker.DoWork += new DoWorkEventHandler(DoMyWork); worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(DoMyWork_Completed); worker.RunWorkerAsync(); Caching like http://www.codeproject.com/KB/aspnet/ASPNETService.aspx (located in Jeff Atwood's post here) I need to run multiple background "services" at a given time. One service may run every 5 minutes where another may be once a day. It will never be more than 10 services running at a time.

    Read the article

  • Can I find out which thread is running using Eclipse?

    - by Roman
    I close my application by pressing a "Close" button. But in the Eclipse I see a red square indicating that something is still running. When I press this red square, I kill my application completely. Is it possible to find out what is still running (which method, which loop) using Eclipse? P.S. I am a newbie. So, it would be nice to have a simple solution. I also might not understand your answer if you use "technical" words which I do not know.

    Read the article

  • How to display data into datagridview using multi thread?

    - by Mark
    Hi, I have application where I read/receive data all the time (text) and I need to display this data into datagridview, what is the best way to do that in real time, so the data will be changed all the time. I thought about multi threading, if this is a good idea can you guide me with link to explain how to implement it. Thanks

    Read the article

  • GetMessage with a timeout

    - by qdii
    I have an application which second thread calls GetMessage() in a loop. At some point the first thread realizes that the user wants to quit the application and notifies the second thread that he should terminate. As the first thread is stuck on GetMessage(), the program never quits. Is there a way to wait for messages with a timeout? I’m open to other ideas too. EDIT: (additional explanations) The second thread runs that snippet of code: while ( !m_quit && GetMessage( &msg, NULL, 0, 0 ) ) { TranslateMessage( &msg ); DispatchMessage( &msg ); } The first thread sets m_quit to true.

    Read the article

  • How to tell which thread(s) are producing all the garbage?

    - by Brad Hein
    I have an app with about 15 threads. Most do mundane tasks and sleep most of their lives. Others collect information and cache it in hashmaps. The hashmaps grow to a moderate size and level out. The number of keys and size of value remains constant, but the contents of the values changes (at 33 keys per second average). When I start my app, I notice the garbage collection interval goes from minutes to once per second, and the amount of garbage is 700k+ each time. In fact as I was writing this, it caused my phone to reboot with an error "Referencetable Overflow". Here's my question: Are there any tricks to identifying which threads are producing the garbage, or even finding out more about what garbage they are producing?

    Read the article

  • breaking out from socket select

    - by kamziro
    I have a loop which basically calls this every few seconds (after the timeout): while(true){ if(finished) return; switch(select(FD_SETSIZE, &readfds, 0, 0, &tv)){ case SOCKET_ERROR : report bad stuff etc; return; default : break; } // do stuff with the incoming connection } So basically for every few seconds (which is specified by tv), it reactivates the listening. This is run on thread B (not a main thread). There are times when I want to end this acceptor loop immediately from thread A (main thread), but seems like I have to wait until the time interval finishes.. Is there a way to disrupt the select function from another thread so thread B can quit instantly?

    Read the article

  • Standard term for a thread I/O reorder buffer?

    - by Crashworks
    I have a case where many threads all concurrently generate data that is ultimately written to one long, serial file. I need to somehow serialize these writes so that the file gets written in the right order. ie, I have an input queue of 2048 jobs j0..jn, each of which produces a chunk of data oi. The jobs run in parallel on, say, eight threads, but the output blocks have to appear in the file in the same order as the corresponding input blocks — the output file has to be in the order o0o1o2... The solution to this is pretty self evident: I need some kind of buffer that accumulates and writes the output blocks in the correct order, similar to a CPU reorder buffer in Tomasulo's algorithm, or to the way that TCP reassembles out-of-order packets before passing them to the application layer. Before I go code it, I'd like to do a quick literature search to see if there are any papers that have solved this problem in a particularly clever or efficient way, since I have severe realtime and memory constraints. I can't seem to find any papers describing this though; a Scholar search on every permutation of [threads, concurrent, reorder buffer, reassembly, io, serialize] hasn't yielded anything useful. I feel like I must just not be searching the right terms. Is there a common academic name or keyword for this kind of pattern that I can search on?

    Read the article

  • Question on a tutorial

    - by hansa
    Hello, i´m trying to get following tutorial to run and understand: http://www.ibm.com/developerworks/web/library/wa-cometjava/index.html In the example code which can be downloaded at the bottom of the page is everything in one class with two inner classes. How can i make the the thread of "MessageSender" (Listing 3) visible to "The Weatherman" (Listing 4) so i can use it in the run method without using inner classes? Thank you hansa Reformulation of Question: How to make the send-method of inner class MessageSender make accessible in ClassThatDoSomething. Example-Code: public class Example extends HttpServlet implements CometProcessor { private MessageSender messageSender = null; @Override public void init() throws ServletException { // starts thread MessageSender } public event(CometEvent) { // Object of ClassThatDoSomething gets created started } private class ClassThatDoSomething { public void start() { Runnable runnable = new Runnable() { public void run(){ messageSender.send(message); } Thread thread = new Thread(runnable); thread.start(); } } private class MessageSender implements Runnable { public void send(String message) { //... } public void run() { //...} } }

    Read the article

  • Run Reporting Service in local mode and generate columns automatically?

    - by grady
    Hi, I have a SQL query right now which I want to use with the MS reporting services in my ASP.NET application. So I created a report in local mode (rdlc) and attached this to a report viewer. Since my query uses parameters, I created a stored procedure, which had exactly those parameters. In addition to that I had some textboxes which are used for entering the params for the query and a button to call the stored proc and to fill the datatset which is bound to the report viewer. This works, I press the button and according to what I entred the correct data is shown. Now my question: In the future I plan to have multiple reports (which will be selected in a dropdown) and I wonder if I can somehow just call the correct stored procedure and according to the columns which are *SELECT*ed in the procedure, the columns are shown in the report. Example: I select report1 from the dropdown (procedure for report 1 is called), 5 columns are shown in the reportviewer. I select report2 from dropdown (procedure for report 2 is called), 8 columns are shown. Is that possible somehow? Thanks :-)

    Read the article

  • How to know who kills my threads

    - by mcabral
    I got a thread that is just banishing.. i'd like to know who is killing my thread and why. It occurs to me my thread is being killed by the OS, but i'd like to confirm this and if possible to know why it's killing it. As for the thread, i can assert it has at least 40 min of execution before dying, but it suddenly dies around 5 min. public void RunWorker() { Thread worker = new Thread(delegate() { DoSomethingForALongLongTime(); }); worker.IsBackground = true; worker.SetApartmentState(System.Threading.ApartmentState.STA); worker.Start(); }

    Read the article

  • How do you calculate the storage size of a SimpleDB domain?

    - by C. Dragon 76
    The official documentation states: Raw byte size (GB) of all item IDs + 45 bytes per item + Raw byte size (GB) of all attribute names + 45 bytes per attribute name + Raw byte size (GB) of all attribute-value pairs + 45 bytes per attribute-value pair What is the raw size of an attribute-value pair? Is it precisely the size of the value? (I would expect so, but then why is it worded "attribute-value pair"?) Or is it the size of the attribute name plus the size of the attribute value? (In that case, there would be motivation to give your attributes really short names.) For example, what is the size of the tiny domain below? +---------------------------------------------------------+ | Item Name/ID | "Price" attribute | "Calories" attribute | |--------------+-------------------+----------------------| | "apple" | "0000.43" | "0046" | | "orange" | "0000.70" | "0053" | +---------------------------------------------------------+

    Read the article

  • More threads and orientation changes questions.

    - by synic
    When it comes to threads and orientation changes, it seems the normal thing to do is something like this: public class Bwent extends Activity { private static Bwent instance; @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); instance = this; } //... That way, if you're making a network request with a thread, and someone changes the orientation of the phone, the thread will know to use the new Activity. However, is it possible that the thread could finish during the time Android is destroying the old Activity and creating a new one? Is there a moment in the process where the thread still might be pointing to the wrong Activity, or a partially destroyed activity? It seems like there shouldn't be, but even using a Handler created in the main thread, I'm having intermittent issues with a thread trying to update an object that no longer exists. It's rare, but it does happen.

    Read the article

  • Is there any way to prevent a Delphi application from using Virtual Storage on Vista/Win 7 without e

    - by croceldon
    The question pretty much says it all. I have an app with an older component that doesn't work right if runtime themes are enabled. But if I don't enable them, the app always ends up messing with the virtual store. Thanks! Update: Using Mark's solution below, the application no longer writes to the Virtual Store. But, now it won't access a tdb file (Tiny Database file) that it needs. This tdb file is the same file that was being written to the Virtual store. Any ideas on how I can give it access to the tdb file and still prevent writing the Virtual Store?

    Read the article

  • Is it possible to have WAMP run httpd.exe as user [myself] instead of local SYSTEM?

    - by Olivier H
    Hello! I run a django application over apache with mod_wsgi, using WAMP. A certain URL allows me to stream the content of image files, the paths of which are stored in database. The files can be located whether on local machine or under network drive (\my\network\folder). With the development server (manage.py runserver), I have no trouble at all reading and streaming the files. With WAMP, and with network drive files, I get a IOError : obviously because the httpd instance does not have read permission on said drive. In the task manager, I see that httpd.exe is run by SYSTEM. I would like to tell WAMP to run the server as [myself] as I have read and write permissions on the shared folder. (eventually, the production server should be run by a 'www-admin' user having the permissions) Mapping the network shared folder on a drive letter (Z: for instance) does not solve this at all. The User/Group directives in httpd.conf do not seem to have any kind of influence on Apache's behaviour. I've also regedited : I tried to duplicate the HKLM[...]\wampapache registry key under HK_CURRENT_USER\ and rename the original key, but then the new key does not seem to be found when I cmd this > httpd.exe -n wampapache -k start or when I run WAMP. I've run out of ideas :) Has anybody ever had the same issue?

    Read the article

  • Stopping process in /etc/inittab kills spawned process. Doesn't happen in rc.local.

    - by Paul
    Hi, I'm trying to execute a firmware upgrade while my programming is running in inittab. My program will run 2 commands. One to extract the installer script from the tarball and the other to execute the installer script. In my code I'm using the system() function call. These are the 2 command strings below, system ( "tar zvxf tarball.tar.gz -C / installer.sh 2>&1" ); system( "nohup installer.sh tarball >/dev/null 2>&1 &" ); The installer script requires the tarball to be an argument. I've tried using sudo but i still have the same problem. I've tried nohup with no success. The installer script has to kill my program when doing the firmware upgrade but the installer script will stay alive. If my program is run from the command line or rc.local, on my target device, my upgrade works fine, i.e. when my program is killed my installer script continues. But I need to run my program from /etc/inittab so it can respawn if it dies. To stop my program in inittab the installer script will hash it out and execute "telinit q". This is where my program dies (but thats what I want it to do), but it also kills my installer script. Does anyone know why this is happening and what can I do to solve it? Thanks in advance.

    Read the article

  • LINQ Changeset multi-threading

    - by Xodarap
    I'm using LINQ to SQL and after I submit some changes I want to spawn a thread which looks through all the changes and updates our lucene index as necessary. My code looks vaguely like: (new Thread(() => { UpdateIndex(context.GetChangeSet()); }).Start(); Sometimes though I get an InvalidOperationException, which I think is because context.GetChangeSet() is not thread-safe, and so if the change set is modified in one thread while another thread is enumerating through it, problems arise. Is there a "thread-safe" version of GetChangeSet()? Or some way I can do ChangeSet.clone() or something?

    Read the article

  • Can a conforming C# compiler optimize away a local (but unused) variable if it is the only strong re

    - by stakx
    The title says it all, but let me explain: void Case_1() { var weakRef = new WeakReference(new object()); GC.Collect(); // <-- doesn't have to be an explicit call; just assume that // garbage collection would occur at this point. if (weakRef.IsAlive) ... } In this code example, I obviously have to plan for the possibility that the new'ed object is reclaimed by the garbage collector; therefore the if statement. (Note that I'm using weakRef for the sole purpose of checking if the new'ed object is still around.) void Case_2() { var unusedLocalVar = new object(); var weakRef = new WeakReference(unusedLocalVar); GC.Collect(); // <-- doesn't have to be an explicit call; just assume that // garbage collection would occur at this point. Debug.Assert(weakReferenceToUseless.IsAlive); } The main change in this code example from the previous one is that the new'ed object is strongly referenced by a local variable (unusedLocalVar). However, this variable is never used again after the weak reference (weakRef) has been created. Question: Is a conforming C# compiler allowed to optimize the first two lines of Case_2 into those of Case_1 if it sees that unusedLocalVar is only used in one place, namely as an argument to the WeakReference constructor? i.e. is there any possibility that the assertion in Case_2 could ever fail?

    Read the article

  • How solve consumer/producer task using semaphores

    - by user1074896
    I have SimpleProducerConsumer class that illustrate consumer/producer problem (I am not sure that it's correct). public class SimpleProducerConsumer { private Stack<Object> stack = new Stack<Object>(); private static final int STACK_MAX_SIZE = 10; public static void main(String[] args) { SimpleProducerConsumer pc = new SimpleProducerConsumer(); new Thread(pc.new Producer(), "p1").start(); new Thread(pc.new Producer(), "p2").start(); new Thread(pc.new Consumer(), "c1").start(); new Thread(pc.new Consumer(), "c2").start(); new Thread(pc.new Consumer(), "c3").start(); } public synchronized void push(Object d) { while (stack.size() >= STACK_MAX_SIZE) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } stack.push(new Object()); System.out.println("push " + Thread.currentThread().getName() + " " + stack.size()); notify(); } public synchronized Object pop() { while (stack.size() == 0) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(50); } catch (InterruptedException e) { e.printStackTrace(); } stack.pop(); System.out.println("pop " + Thread.currentThread().getName() + " " + stack.size()); notify(); return null; } class Consumer implements Runnable { @Override public void run() { while (true) { pop(); } } } class Producer implements Runnable { @Override public void run() { while (true) { push(new Object()); } } } } I found simple realization of semaphore(here:http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html I know that there is concurrency package) How I need to change code to exchange java objects monitors to my custom semaphore. (To illustrate C/P problem using semaphores) Semaphore: class Semaphore { private int counter; public Semaphore() { this(0); } public Semaphore(int i) { if (i < 0) throw new IllegalArgumentException(i + " < 0"); counter = i; } public synchronized void release() { if (counter == 0) { notify(); } counter++; } public synchronized void acquire() throws InterruptedException { while (counter == 0) { wait(); } counter--; } }

    Read the article

  • How do I make a lock that allows only ONE thread to read from the resource ?

    - by mare
    I have a file that holds an integer ID value. Currently reading the file is protected with ReaderWriterLockSlim as such: public int GetId() { _fileLock.EnterUpgradeableReadLock(); int id = 0; try { if(!File.Exists(_filePath)) CreateIdentityFile(); FileStream readStream = new FileStream(_filePath, FileMode.Open, FileAccess.Read); StreamReader sr = new StreamReader(readStream); string line = sr.ReadLine(); sr.Close(); readStream.Close(); id = int.Parse(line); return int.Parse(line); } finally { SaveNextId(id); // increment the id _fileLock.ExitUpgradeableReadLock(); } } The problem is that subsequent actions after GetId() might fail. As you can see the GetId() method increments the ID every single time, disregarding what happens after it has issued an ID. The issued ID might be left hanging (as said, exceptions might occur). As the ID is incremented, some IDs might be left unused. So I was thinking of moving the SaveNextId(id) out, remove it (the SaveNextId() actually uses the lock too, except that it's EnterWriteLock). And call it manually from outside after all the required methods have executed. That brings out another problem - multiple threads might enter the GetId() method before the SaveNextId() gets executed and they might all receive the same ID. I don't want any solutions where I have to alter the IDs after the operation, correcting them in any way because that's not nice and might lead to more problems. I need a solution where I can somehow callback into the FileIdentityManager (that's the class that handles these IDs) and let the manager know that it can perform the saving of the next ID and then release the read lock on the file containing the ID. Essentialy I want to replicate the relational databases autoincrement behaviour - if anything goes wrong during row insertion, the ID is not used, it is still available for use but it also never happens that the same ID is issued. Hopefully the question is understandable enough for you to provide some solutions..

    Read the article

  • Python sqlite3 and concurrency

    - by RexE
    I have a Python program that uses the "threading" module. Once every second, my program starts a new thread that fetches some data from the web, and stores this data to my hard drive. I would like to use sqlite3 to store these results, but I can't get it to work. The issue seems to be about the following line: conn = sqlite3.connect("mydatabase.db") If I put this line of code inside each thread, I get an OperationalError telling me that the database file is locked. I guess this means that another thread has mydatabase.db open through a sqlite3 connection and has locked it. If I put this line of code in the main program and pass the connection object (conn) to each thread, I get a ProgrammingError, saying that SQLite objects created in a thread can only be used in that same thread. Previously I was storing all my results in CSV files, and did not have any of these file-locking issues. Hopefully this will be possible with sqlite. Any ideas?

    Read the article

  • How do I know that a process has more than 1 thread?

    - by Richard77
    I'have typed ps -ALF and got the following results. Actually there are more to the tow lines that I typed. UID PID PPID LWP C NLWP SZ RSS PSR STIME TTY TIME CMD root 1 0 1 0 1 5900 1644 1 Nov05 ? 00:00:05 /sbin/init root 2 0 2 0 1 0 0 0 Nov05 ? 00:00:00 [kthreadd] I'm supposed to find which process has more than 1 threads. Which column am I supposed to examine? Thanks for helping

    Read the article

  • Communication between Multiple Threads in a WPF Application

    - by Robert
    I'm creating a WPF application that uses a custom object to populate all the controls. The constructor of that object is initiated by an EventHandler that waits for an API. The problem I'm having is when I try to access any information from that object using a button for example, it returns an error saying "The calling thread cannot access this object because a different thread owns it". I'm assuming this is because the EventHandler creates a new thread which doesn't allow the Main Thread to have access to it. Any ideas on how to get around this? I'm basically having the error "The calling thread cannot access this object because a different thread owns it" when trying to get or set a CollectionViewSource.

    Read the article

< Previous Page | 206 207 208 209 210 211 212 213 214 215 216 217  | Next Page >