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  • How can I load a Class contained in a website from a DLL referenced by that website???

    - by Morgeh
    Ok so this is alittle bit obscure and I'm not sure its the best way of doing what I'm trying to do but here goes. Basically I have a Presentation Layer Dll in my web site which handles the Model View Presenter classes. The presentation layer also handles login for my website and then calls off to a web service. Currently whenever the presentation layer calls to a model it verifies the users details and if they are invalid it calls to a loginHandler which redirects the user to the login page. However I cannot dynamically load a new istance of the Login Page in my website from within my Presentation layer. I've tried to use reflection to dynamically load the class but Since the method call is in the presentation assembly it is only looking within that assembly while the page I want to load is in the website. heres the reflection code that loads the View: public ILoginView LoadView() { string viewName = ConfigurationManager.AppSettings["LoginView"].ToString(); Type type = Type.GetType(viewName, true); object newInstance = Activator.CreateInstance(type); return newInstance as ILoginView; } Anyone got any suggestions on how to search within the website assembly? Ideal I don't want to tie this implementation into the website specifically as the presentation layer is also used in a WPF application.

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  • Can I spead out a long running stored proc accross multiple CPU's?

    - by Russ
    [Also on SuperUser - http://superuser.com/questions/116600/can-i-spead-out-a-long-running-stored-proc-accross-multiple-cpus] I have a stored procedure in SQL server the gets, and decrypts a block of data. ( Credit cards in this case. ) Most of the time, the performance is tolerable, but there are a couple customers where the process is painfully slow, taking literally 1 minute to complete. ( Well, 59377ms to return from SQL Server to be exact, but it can vary by a few hundred ms based on load ) When I watch the process, I see that SQL is only using a single proc to perform the whole process, and typically only proc 0. Is there a way I can change my stored proc so that SQL can multi-thread the process? Is it even feasible to cheat and to break the calls in half, ( top 50%, bottom 50% ), and spread the load, as a gross hack? ( just spit-balling here ) My stored proc: USE [Commerce] GO /****** Object: StoredProcedure [dbo].[GetAllCreditCardsByCustomerId] Script Date: 03/05/2010 11:50:14 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[GetAllCreditCardsByCustomerId] @companyId UNIQUEIDENTIFIER, @DecryptionKey NVARCHAR (MAX) AS SET NoCount ON DECLARE @cardId uniqueidentifier DECLARE @tmpdecryptedCardData VarChar(MAX); DECLARE @decryptedCardData VarChar(MAX); DECLARE @tmpTable as Table ( CardId uniqueidentifier, DecryptedCard NVarChar(Max) ) DECLARE creditCards CURSOR FAST_FORWARD READ_ONLY FOR Select cardId from CreditCards where companyId = @companyId and Active=1 order by addedBy desc --2 OPEN creditCards --3 FETCH creditCards INTO @cardId -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN --OPEN creditCards DECLARE creditCardData CURSOR FAST_FORWARD READ_ONLY FOR select convert(nvarchar(max), DecryptByCert(Cert_Id('Oh-Nay-Nay'), EncryptedCard, @DecryptionKey)) FROM CreditCardData where cardid = @cardId order by valueOrder OPEN creditCardData FETCH creditCardData INTO @tmpdecryptedCardData -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN print 'CreditCardData' print @tmpdecryptedCardData set @decryptedCardData = ISNULL(@decryptedCardData, '') + @tmpdecryptedCardData print '@decryptedCardData' print @decryptedCardData; FETCH NEXT FROM creditCardData INTO @tmpdecryptedCardData -- fetch next END CLOSE creditCardData DEALLOCATE creditCardData insert into @tmpTable (CardId, DecryptedCard) values ( @cardId, @decryptedCardData ) set @decryptedCardData = '' FETCH NEXT FROM creditCards INTO @cardId -- fetch next END select CardId, DecryptedCard FROM @tmpTable CLOSE creditCards DEALLOCATE creditCards

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  • Can I spread out a long running stored proc accross multiple CPU's?

    - by Russ
    [Also on SuperUser - http://superuser.com/questions/116600/can-i-spead-out-a-long-running-stored-proc-accross-multiple-cpus] I have a stored procedure in SQL server the gets, and decrypts a block of data. ( Credit cards in this case. ) Most of the time, the performance is tolerable, but there are a couple customers where the process is painfully slow, taking literally 1 minute to complete. ( Well, 59377ms to return from SQL Server to be exact, but it can vary by a few hundred ms based on load ) When I watch the process, I see that SQL is only using a single proc to perform the whole process, and typically only proc 0. Is there a way I can change my stored proc so that SQL can multi-thread the process? Is it even feasible to cheat and to break the calls in half, ( top 50%, bottom 50% ), and spread the load, as a gross hack? ( just spit-balling here ) My stored proc: USE [Commerce] GO /****** Object: StoredProcedure [dbo].[GetAllCreditCardsByCustomerId] Script Date: 03/05/2010 11:50:14 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[GetAllCreditCardsByCustomerId] @companyId UNIQUEIDENTIFIER, @DecryptionKey NVARCHAR (MAX) AS SET NoCount ON DECLARE @cardId uniqueidentifier DECLARE @tmpdecryptedCardData VarChar(MAX); DECLARE @decryptedCardData VarChar(MAX); DECLARE @tmpTable as Table ( CardId uniqueidentifier, DecryptedCard NVarChar(Max) ) DECLARE creditCards CURSOR FAST_FORWARD READ_ONLY FOR Select cardId from CreditCards where companyId = @companyId and Active=1 order by addedBy desc --2 OPEN creditCards --3 FETCH creditCards INTO @cardId -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN --OPEN creditCards DECLARE creditCardData CURSOR FAST_FORWARD READ_ONLY FOR select convert(nvarchar(max), DecryptByCert(Cert_Id('Oh-Nay-Nay'), EncryptedCard, @DecryptionKey)) FROM CreditCardData where cardid = @cardId order by valueOrder OPEN creditCardData FETCH creditCardData INTO @tmpdecryptedCardData -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN print 'CreditCardData' print @tmpdecryptedCardData set @decryptedCardData = ISNULL(@decryptedCardData, '') + @tmpdecryptedCardData print '@decryptedCardData' print @decryptedCardData; FETCH NEXT FROM creditCardData INTO @tmpdecryptedCardData -- fetch next END CLOSE creditCardData DEALLOCATE creditCardData insert into @tmpTable (CardId, DecryptedCard) values ( @cardId, @decryptedCardData ) set @decryptedCardData = '' FETCH NEXT FROM creditCards INTO @cardId -- fetch next END select CardId, DecryptedCard FROM @tmpTable CLOSE creditCards DEALLOCATE creditCards

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  • Can I spread out a long running stored proc accross multiple CPU's?

    - by Russ
    [Also on SuperUser - http://superuser.com/questions/116600/can-i-spead-out-a-long-running-stored-proc-accross-multiple-cpus] I have a stored procedure in SQL server the gets, and decrypts a block of data. ( Credit cards in this case. ) Most of the time, the performance is tolerable, but there are a couple customers where the process is painfully slow, taking literally 1 minute to complete. ( Well, 59377ms to return from SQL Server to be exact, but it can vary by a few hundred ms based on load ) When I watch the process, I see that SQL is only using a single proc to perform the whole process, and typically only proc 0. Is there a way I can change my stored proc so that SQL can multi-thread the process? Is it even feasible to cheat and to break the calls in half, ( top 50%, bottom 50% ), and spread the load, as a gross hack? ( just spit-balling here ) My stored proc: USE [Commerce] GO /****** Object: StoredProcedure [dbo].[GetAllCreditCardsByCustomerId] Script Date: 03/05/2010 11:50:14 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[GetAllCreditCardsByCustomerId] @companyId UNIQUEIDENTIFIER, @DecryptionKey NVARCHAR (MAX) AS SET NoCount ON DECLARE @cardId uniqueidentifier DECLARE @tmpdecryptedCardData VarChar(MAX); DECLARE @decryptedCardData VarChar(MAX); DECLARE @tmpTable as Table ( CardId uniqueidentifier, DecryptedCard NVarChar(Max) ) DECLARE creditCards CURSOR FAST_FORWARD READ_ONLY FOR Select cardId from CreditCards where companyId = @companyId and Active=1 order by addedBy desc --2 OPEN creditCards --3 FETCH creditCards INTO @cardId -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN --OPEN creditCards DECLARE creditCardData CURSOR FAST_FORWARD READ_ONLY FOR select convert(nvarchar(max), DecryptByCert(Cert_Id('Oh-Nay-Nay'), EncryptedCard, @DecryptionKey)) FROM CreditCardData where cardid = @cardId order by valueOrder OPEN creditCardData FETCH creditCardData INTO @tmpdecryptedCardData -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN print 'CreditCardData' print @tmpdecryptedCardData set @decryptedCardData = ISNULL(@decryptedCardData, '') + @tmpdecryptedCardData print '@decryptedCardData' print @decryptedCardData; FETCH NEXT FROM creditCardData INTO @tmpdecryptedCardData -- fetch next END CLOSE creditCardData DEALLOCATE creditCardData insert into @tmpTable (CardId, DecryptedCard) values ( @cardId, @decryptedCardData ) set @decryptedCardData = '' FETCH NEXT FROM creditCards INTO @cardId -- fetch next END select CardId, DecryptedCard FROM @tmpTable CLOSE creditCards DEALLOCATE creditCards

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  • DDK/WDM developing problem ... driver won't load on x64 windows platform

    - by user295975
    Hi there! I am a beginner at DDK/WDM driver developing field. I have a task which involves porting a virtual device driver from x86 to x64 (intel). I got the source code, I modified it a bit and compiled it succesfuly with DDK (build environments). But when I tried to load it on a ia64 Windows7 machine it didn't want to load. Then I tried some simple examples of device drivers from --http://www.codeproject.com/KB/system/driverdev.aspx (I put '--' to be able to post the hyperlink) and from other links but still the same problem. I hear on a forum that some libraries that you use to link are not compatible with the new machines and suggested to link to another similar libraries...but still didn't worked. When I build I use "-cefw" command line parameters as suggested. I do not have an *.inf file asociated but I'm copying it in system32/drivers and I'm using WinObj to see if next restart it's loaded into the memory. I also tried this program ( http://www.codeproject.com/KB/system/tdriver.aspx ) to load the driver into the memory but still didn't worked for me. Please please help me...I'm stuck on this and my deadline already passed. I feel I'driving nuts in here trying to discover what am I doing wrong.

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  • How do I invoke a SimpleModal OSX dialog on page load?

    - by Priyank Sharma
    I was wondering if there is a way to invoke the SimpleModal OSX dialog box on page load? I tried http://stackoverflow.com/questions/522864/open-jquery-modal-dialog-on-page-load but wasn't able to make it happen. Currently, the dialog is invoked on clicking a button / link. I would like to invoke it on page load. Please help. :) Thanks! <script type='text/javascript' src='js/jquery.js'></script> <script type='text/javascript' src='js/jquery.simplemodal.js'></script> <script type='text/javascript' src='js/osx.js'></script> <input type='button' name='osx' value='Demo' class='osx demo'/> or <a href='#' class='osx'>Demo</a> <div id="osx-modal-content"> <div id="osx-modal-data"> <h2>Hello! I'm SimpleModal!</h2> <p><button class="simplemodal-close">Close</button> <span>(or press ESC or click the overlay)</span></p> </div> </div>

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  • Implementing eval and load functions inside a scripting engine with Flex and Bison.

    - by Simone Margaritelli
    Hy guys, i'm developing a scripting engine with flex and bison and now i'm implementing the eval and load functions for this language. Just to give you an example, the syntax is like : import std.*; load( "some_script.hy" ); eval( "foo = 123;" ); println( foo ); So, in my lexer i've implemented the function : void hyb_parse_string( const char *str ){ extern int yyparse(void); YY_BUFFER_STATE prev, next; /* * Save current buffer. */ prev = YY_CURRENT_BUFFER; /* * yy_scan_string will call yy_switch_to_buffer. */ next = yy_scan_string( str ); /* * Do actual parsing (yyparse calls yylex). */ yyparse(); /* * Restore previous buffer. */ yy_switch_to_buffer(prev); } But it does not seem to work. Well, it does but when the string (loaded from a file or directly evaluated) is finished, i get a sigsegv : Program received signal SIGSEGV, Segmentation fault. 0xb7f2b801 in yylex () at src/lexer.cpp:1658 1658 if ( YY_CURRENT_BUFFER_LVALUE->yy_buffer_status == YY_BUFFER_NEW ) As you may notice, the sigsegv is generated by the flex/bison code, not mine ... any hints, or at least any example on how to implement those kind of functions? PS: I've succesfully implemented the include directive, but i need eval and load to work not at parsing time but execution time (kind of PHP's include/require directives).

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  • What is the space character for the browser?

    - by Hiro Protagonist
    echo "\n\s\s\s\s\s\s" . "<div id='data-load' data-load='" . $load . "'></div>"; \n works for adding a return in...I tried \s logically for space but this does not work. Keep mind, I don't want this rendered in the browser view...but in the source view ( when you click view-source )...I'm trying to put my html in to a readable form. echo "&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp\n" . "<div id='data-path' data-path='" . $path . "'></div>"; This does not work either. I am composing HTML from PHP... echo " \n" . "<div id='data-load' data-load='" . $load . "'></div>"; This does not work either. Actual Code: public static function setUniversals() { $shared_object = new Shared(); if ( $shared_object->getLoadOn() == 1 ) { $load = 'server'; } else { $load = 'client'; } if( getcwd() === '/home/foo/public_html/develop' ) { $path = 'development'; } else { $path = 'production'; } $shared_object = new Shared(); echo "\n"; echo "\n " . "<div id='data-path' data-path='" . $path . "'></div>"; echo "\n " . "<div id='data-load' data-load='" . $load . "'></div>"; }

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  • Can I make Thunderbird load different email accounts one after the other instead of all at the same

    - by Martin
    I use Thunderbird 3 on Vista. I use it for 3 POP accounts. When I start work in the morning, all three accounts are checked at the same time, and all emails are being loaded simultaneously. I think Thunderbird is quite slow in general, and this behaviour makes it even worse. At least it makes me feel so. Can I tell Thunderbird to check the accounts and load the emails one after the other?

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  • Small website on Amazon EC2 Linux: a single large instance or more small instances in load balancing?

    - by Enrico Detoma
    I need to run a small website with a JSON webservice on Amazon EC2 Linux. The largest number of requests come from the JSON webservice, which provides some load in terms of MySQL queries. I'm trying to decide between two choices: A single large instance (Ubuntu 12.04 64-bit) with full LAMP stack or One or two small instances (Ubuntu 12.04 64-bit) with Apache/PHP only One small instance dedicated to MySQL (or RDS) Which setup would you consider to be more performant?

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  • Can I do this?? Trying to load an object from within itself.

    - by Smikey
    Hi all! I have an object which conforms to the NSCoding protocol. The object contains a method to save itself to memory, like so: - (void)saveToFile { NSMutableData *data = [[NSMutableData alloc] init]; NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data]; [archiver encodeObject:self forKey:kDataKey]; [archiver finishEncoding]; [data writeToFile:[self dataFilePath] atomically:YES]; [archiver release]; [data release]; } This works just fine. But I would also like to initialise an empty version of this object and then call its own 'Load' method to load whatever data exists on file into its variables. So I've created the following: - (void)loadFromFile { NSString *filePath = [self dataFilePath]; if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) { NSData *data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]]; NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data]; self = [unarchiver decodeObjectForKey:kDataKey]; [unarchiver finishDecoding]; } } Now this second method doesn't manage to load any variables. Is this line not possible perhaps? self = [unarchiver decodeObjectForKey:kDataKey]; Ultimately I would like to use the code like this: One viewController takes user entered input, creates an object and saves it to memory using [anObject saveToFile]; And a second viewController creates an empty object, then initialises its values to those stored on file by calling: [emptyObject loadFromFile]; Any suggestions on how to make this work would be hugely appreciated. Thanks :) Michael

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  • What DNS server to use for dynamic load-balancing of website?

    - by Marki555
    I will have 2 servers in different datacenters (different countries) and I want to use DNS load-balancing mainly for High Availability of website hosted on those 2 servers. It is just ad tracking site, which records hit in local database and returns few lines on html code. I want to return 2 A records each time because of DNS pinning in browsers (if one server fails, browser will try second A record which it has already cached). Both servers will be acting also as DNS servers for redundancy. Now comes my proposed solution: I will use BIND and have both servers as a master for that zone. On each server there will be running script, which will periodically test availability (http) of both servers and remove IP from DNS in case of failure. Now the questions :) 1) Is BIND suitable for this solution? I think BIND performance is good and it is easy to manipulate the zone file via script. And as I will modify the zone only in case of failure/maintenance, the modifications (and thus bind reload) won't be often. 2) I plan to use TTL of 5 minutes. The website will have about 1000-3000 req/s but from distinct clients (each IP only 1-3 requests), so I think the DNS load won't be too much. I suppose their ISPs will cache the responses for those 5 mins. Is there any reason to lower the TTL even more? 3) Is my master-master approach good? Or should I make one of the servers master and the other one slave? Right now each server can monitor both itself and the other one. If only webservice fails, both DNS nodes will notice it. If the whole server fails, then the remaining DNS node will notice it and the failed node will not answer DNS queries anyway. 4) Is it a big issue when one NS server does not respond to queries? If yes, I can make a third DNS, so anytime at least 2 of them would accept queries... 5) Should I rewrite the zone file via script, or just use dynamic DNS update (for example via nsupdateutility)?

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  • I cannot seem to load an XML document using ASP (Classic), IIS6. Details inside.

    - by carny666
    So I am writing a web application for use within my organization. The application requires that it know who the current user is. This is done by calling the Request.ServerVariables("AUTH_USER") function, which works great as long as 'Anonymous Access' is disabled (unchecked) and 'Integrated Windows Authentication' is enabled (checked) within IIS for this subweb. Unfortunately by doing this I get an 'Access Denied' error when I hit the load method of the XML DOM. Example code: dim urlToXmlFile urlToXmlFile = "http://currentwebserver/currentsubweb/nameofxml.xml" dim xmlDom set xmlDom = Server.CreateObject("MSXML2.DOMDocument") xmlDom.async = false xmlDom.load( urlToXmlFile ) ' <-- this is where I get the error! I've looked everywhere and cannot find a solution. I should be able to load an XML file into the DOM regardless of the authentication method. Any help would be appreciated. So far the only two solutions I can come up with are: a) create a new subweb that JUST gets the current user name and somehow passes it back to my XML reading subweb. b) open up security on the entire system to 'Everyone', which works but our IS department wouldn't care for that.

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  • How to load kernel module at startup on FC9?

    - by dicroce
    I need to know how to automatically load a kernel module at startup on FC9. All the sites talk about adding an entry to /etc/modules.conf.... But that does not exist on FC9... Instead I have /etc/modprobe.d/ directory... Now, I suppose I need to put a file in this dir for my driver but I have no idea how to write this file... I just need "modprobe name" to be run...

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  • if i have two external hard drives connected to my computer by USB (2.0 i think) will they load with consistent letters?

    - by Bec
    (I'm using windows-7 and the hard drives are western digital with whatever formatting they came with from the factory) i'm thinking of setting up two different back-ups one through windows and one with the software that came with the drive (because windows gives me a system image but isn't very user-friendly for my files) but will my computer get confused and load them as different letters each time?

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  • .NET Code Evolution

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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  • Scheme Formatting Help

    - by Logan
    I've been working on a project for school that takes functions from a class file and turns them into object/classes. The assignment is all about object oriented programming in scheme. My problem however is that my code doesn't format right. The output it gives me whenever I give it a file to pass in wraps the methods of the class in a list, making it so that the class never really gets declared. I can't for the life of me figure out how to get the parenthesis wrapping the method list to remove. I would really appreciate any help. Below is the code and the class file. ;;;; PART1 --- A super-easy set of classes. Just models points and lines. Tests all of the ;; basics of class behavior without touching on anything particularly complex. (class pointInstance (parent:) (constructor_args:) (ivars: (myx 1) (myy 2)) (methods: (getx () myx) (gety () myy) (setx (x) (set! myx x)) (show () (begin (display "[") (display myx) (display ",") (display myy) (display "]"))) )) (require (lib "trace.ss")) ;; Continue reading until you hit the end of the file, all the while ;; building a list with the contents (define load-file (lambda (port) (let ((rec (read port))) (if (eof-object? rec) '() (cons rec (load-file port)))))) ;; Open a port based on a file name using open-input-file (define (load fname) (let ((fport (open-input-file fname))) (load-file fport))) ;(define lis (load "C:\\Users\\Logan\\Desktop\\simpletest.txt")) ;(define lis (load "C:\\Users\\Logan\\Desktop\\complextest.txt")) (define lis (load "C:\\Users\\Logan\\Desktop\\pointinstance.txt")) ;(display (cdaddr (cdddar lis))) (define makeMethodList (lambda (listToMake retList) ;(display listToMake) (cond [(null? listToMake) retList ;(display "The list passed in to parse was null") ] [else (makeMethodList (cdr listToMake) (append retList (list (getMethodLine listToMake)))) ] ) )) ;(trace makeMethodList) ;this works provided you just pass in the function line (define getMethodLine (lambda (functionList) `((eq? (car msg) ,(caar functionList)) ,(caddar functionList)))) (define load-classes (lambda paramList (cond [(null? paramList) (display "Your parameters are null, man.")] [(null? (car paramList))(display "Done creating class definitions.")] [(not (null? (car paramList))) (begin (let* ((className (cadaar paramList)) (classInstanceVars (cdaddr (cddaar paramList))) (classMethodList (cdr (cadddr (cddaar paramList)))) (desiredMethodList (makeMethodList classMethodList '())) ) ;(display "Classname: ") ;(display className) ;(newline)(newline) ;(display "Class Instance Vars: ") ;(display classInstanceVars) ;(newline)(newline) ;(display "Class Method List: ") ;(display classMethodList) ;(newline) ;(display "Desired Method List: ") ;(display desiredMethodList)) ;(newline)(newline) ;---------------------------------------------------- ;do not delete the below code!` `(define ,className (let ,classInstanceVars (lambda msg ;return the function list here (cond ,(makeMethodList classMethodList '()))) )) ;--------------------------------------------------- ))] ) )) (load-classes lis) ;(load-classes lis) ;(load-classes-helper lis) ;(load-classes "simpletest.txt") ;(load-classes "complextest.txt") ;method list ;(display (cdr (cadddr (cddaar <class>))))

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  • Should an object be fully complete before injected as a dependency?

    - by Hans
    This is an extension of this question: http://stackoverflow.com/questions/3027082/understanding-how-to-inject-object-dependencies. Since it is a bit different, I wanted to separate them, to make it, hopefully, easier to answer. Also, this is not a real system, just a simplified example that I thought we'd all be familiar with. TIA. : DB threads: thread_id, thread_name, etc posts: post_id, thread_id, post_name, post_contents, post_date, post_user_id, etc Overview Basically I'm looking at the most maintainable way to load $post_id and have it cascade and load the other things I want to know about and I'm trying to keep the controller skinny. BUT: I'm ending up with too many dependencies to inject I'm passing in initialized but empty objects I want to limit how many parameters I am passing around I could inject $post(-many) into $thread(one<-), but on that page I'm not looking at a thread, I'm looking at a post I could combine/inject them into a new object Detail If I am injecting an object into another, is it best to have it fully created first? I'm trying to limit how many parameters I have to pass in to a page, but I end up with a circle. // 1, empty object injected via constructor $thread = new Thread; $post = new Post($thread); // $thread is just an empty object $post->load($post_id); // I could now do something like $post->get('thread_id') to get everything I want in $post // 2, complete object injected via constructor $thread = new Thread; $thread->load($thread_id); // this page would have to have passed in a $thread_id, too $post = new Post($thread); // thread is a complete object, with the data I need, like thread name $post->load($post_id); // 3, inject $post into $thread, but this makes less sense to me, since I'm looking at a post page, not a thread page $post = new Post(); $post->load($post_id); $thread = new Thread($post); $thread->load(); // would load based on the $post->get('post_id') and combine. Now I have all the data I want, but it's non-intuitive to be heirarchially Thread->Post instead of Post-with-thread-info // Or, I could inject $post into $thread, but if I'm on a post page, // having an object with a top level of Thread instead of // Post-which-contains-thread-info, makes less sense to me. // to go with example 1 class post { public function __construct(&$thread) { $this->thread=$thread; } public function load($id) { // ... here I would load all the post data based on $id // now include the thread data $this->thread->load($this->get('thread_id')); return $this; } } // I don't want to do $thread = new Thread; $post = new Post; $post->load($post_id); $thread->load($post->get('post_id')); Or, I could create a new object and inject both $post and $thread into it, but then I have object with an increasing number of dependencies.

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  • Is this the right way to get the grand total of processors with WMI on a multi-cpu system?

    - by John Sheares
    I don't have access to a multi-socketed computer, so I am unsure if the following will get the grand total of processors and logical processors. I assume ManagementObjectSearcher will return an instance for each socketed CPU and I just keep a running total? int totalCPUs = 0; int totalLogicalCPUs = 0; ManagementObjectSearcher mos = new ManagementObjectSearcher("Select * from Win32_ComputerSystem"); foreach (var mo in mos.Get()) { string num = mo.Properties["NumberOfProcessors"].Value.ToString(); totalCPUs += Convert.ToInt32(num); num = mo.Properties["NumberOfLogicalProcessors"].Value.ToString(); totalLogicalCPUs += Convert.ToInt32(num); }

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  • Any strategies for assessing the trade-off between CPU loss and memory gain from compression of data

    - by indiehacker
    Are very large TextProperties a burden? Should they be compressed? Say I have a information stored in 2 attributes of type TextProperty in my datastore entities. The strings are always the same length of 65,000 characters and have lots of repeating integers, a sample appearing as follows: entity.pixel_idx = 0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,5,5,5,5,5,5,5,5,5,5,5,5....etc. entity.pixel_color = 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,1,1,1,...etc. So these above could also be represented using much less storage memory by compressing say using only each integer and the length of its series ( '0,8' for '0,0,0,0,0,0,0,0') but then its takes time and CPU to compress and decompress? Any general ideas? Are there some tricks for testing different attempts to the problem?

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  • mysql does not utilize my cpu and ram enough?

    - by vick
    Hello Everyone! I am importing a 2.5gb csv file to a mysql table. My storage engine is innodb. Here is the script: use xxx; DROP TABLE IF EXISTS `xxx`.`xxx`; CREATE TABLE `xxx`.`xxx` ( `xxx_id` int(10) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(128) NOT NULL, `yy` varchar(128) NOT NULL, `yyy` varchar(64) NOT NULL, `yyyy` varchar(2) NOT NULL, `yyyyy` varchar(10) NOT NULL, `url` varchar(64) NOT NULL, `p` varchar(10) NOT NULL, `pp` varchar(10) NOT NULL, `category` varchar(256) NOT NULL, `flag` varchar(4) NOT NULL, PRIMARY KEY (`xxx_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; set autocommit = 0; load data local infile '/home/xxx/raw.csv' into table company fields terminated by ',' optionally enclosed by '"' lines terminated by '\r\n' ( name, yy, yyy, yyyy, yyyyy, url, p, pp, category, flag ); commit; Why does my PC (core i7 920 with 6gb ram) only consume 9% cpu power and 60% ram when running these queries?

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  • Ingame menu is not working correctly

    - by Johnny
    The ingame menu opens when the player presses Escape during the main game. If the player presses Y in the ingame menu, the game switches to the main menu. Up to here, everything works. But: On the other hand, if the player presses N in the ingame menu, the game should switch back to the main game(should resume the main game). But that doesn't work. The game just rests in the ingame menu if the player presses N. I set a breakpoint in this line of the Ingamemenu class: KeyboardState kbState = Keyboard.GetState(); CurrentSate/currentGameState and LastState/lastGameState have the same state: IngamemenuState. But LastState/lastGameState should not have the same state than CurrentSate/currentGameState. What is wrong? Why is the ingame menu not working correctly? public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; IState lastState, currentState; public enum GameStates { IntroState = 0, MenuState = 1, MaingameState = 2, IngamemenuState = 3 } public void ChangeGameState(GameStates newState) { lastGameState = currentGameState; lastState = currentState; switch (newState) { case GameStates.IntroState: currentState = new Intro(this); currentGameState = GameStates.IntroState; break; case GameStates.MenuState: currentState = new Menu(this); currentGameState = GameStates.MenuState; break; case GameStates.MaingameState: currentState = new Maingame(this); currentGameState = GameStates.MaingameState; break; case GameStates.IngamemenuState: currentState = new Ingamemenu(this); currentGameState = GameStates.IngamemenuState; break; } currentState.Load(Content); } public void ChangeCurrentToLastGameState() { currentGameState = lastGameState; currentState = lastState; } public GameStates CurrentState { get { return currentGameState; } set { currentGameState = value; } } public GameStates LastState { get { return lastGameState; } set { lastGameState = value; } } private GameStates currentGameState = GameStates.IntroState; private GameStates lastGameState; public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; } protected override void Initialize() { ChangeGameState(GameStates.IntroState); base.Initialize(); } protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); currentState.Load(Content); } protected override void Update(GameTime gameTime) { currentState.Update(gameTime); if ((lastGameState == GameStates.MaingameState) && (currentGameState == GameStates.IngamemenuState)) { lastState.Update(gameTime); } base.Update(gameTime); } protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); if ((lastGameState == GameStates.MaingameState) && (currentGameState == GameStates.IngamemenuState)) { lastState.Render(spriteBatch); } currentState.Render(spriteBatch); spriteBatch.End(); base.Draw(gameTime); } } public interface IState { void Load(ContentManager content); void Update(GameTime gametime); void Render(SpriteBatch batch); } public class Intro : IState { Texture2D Titelbildschirm; private Game1 game1; public Intro(Game1 game) { game1 = game; } public void Load(ContentManager content) { Titelbildschirm = content.Load<Texture2D>("gruft"); } public void Update(GameTime gametime) { KeyboardState kbState = Keyboard.GetState(); if (kbState.IsKeyDown(Keys.Space)) game1.ChangeGameState(Game1.GameStates.MenuState); } public void Render(SpriteBatch batch) { batch.Draw(Titelbildschirm, new Rectangle(0, 0, 1280, 720), Color.White); } } public class Menu:IState { Texture2D Choosescreen; private Game1 game1; public Menu(Game1 game) { game1 = game; } public void Load(ContentManager content) { Choosescreen = content.Load<Texture2D>("menubild"); } public void Update(GameTime gametime) { KeyboardState kbState = Keyboard.GetState(); if (kbState.IsKeyDown(Keys.Enter)) game1.ChangeGameState(Game1.GameStates.MaingameState); if (kbState.IsKeyDown(Keys.Escape)) game1.Exit(); } public void Render(SpriteBatch batch) { batch.Draw(Choosescreen, new Rectangle(0, 0, 1280, 720), Color.White); } } public class Maingame : IState { Texture2D Spielbildschirm, axe; Vector2 position = new Vector2(100,100); private Game1 game1; public Maingame(Game1 game) { game1 = game; } public void Load(ContentManager content) { Spielbildschirm = content.Load<Texture2D>("hauszombie"); axe = content.Load<Texture2D>("axxx"); } public void Update(GameTime gametime) { KeyboardState keyboardState = Keyboard.GetState(); float delta = (float)gametime.ElapsedGameTime.TotalSeconds; position.X += 5 * delta; position.Y += 3 * delta; if (keyboardState.IsKeyDown(Keys.Escape)) game1.ChangeGameState(Game1.GameStates.IngamemenuState); } public void Render(SpriteBatch batch) { batch.Draw(Spielbildschirm, new Rectangle(0, 0, 1280, 720), Color.White); batch.Draw(axe, position, Color.White); } } public class Ingamemenu : IState { Texture2D Quitscreen; private Game1 game1; public Ingamemenu(Game1 game) { game1 = game; } public void Load(ContentManager content) { Quitscreen = content.Load<Texture2D>("quit"); } public void Update(GameTime gametime) { KeyboardState kbState = Keyboard.GetState(); if (kbState.IsKeyDown(Keys.Y)) game1.ChangeGameState(Game1.GameStates.MenuState); if (kbState.IsKeyDown(Keys.N)) game1.ChangeCurrentToLastGameState(); } public void Render(SpriteBatch batch) { batch.Draw(Quitscreen, new Rectangle(200, 200, 200, 200), Color.White); } }

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