Search Results

Search found 10883 results on 436 pages for 'thread timeout'.

Page 16/436 | < Previous Page | 12 13 14 15 16 17 18 19 20 21 22 23  | Next Page >

  • Cache consistency & spawning a thread

    - by Dave Keck
    Background I've been reading through various books and articles to learn about processor caches, cache consistency, and memory barriers in the context of concurrent execution. So far though, I have been unable to determine whether a common coding practice of mine is safe in the strictest sense. Assumptions The following pseudo-code is executed on a two-processor machine: int sharedVar = 0; myThread() { print(sharedVar); } main() { sharedVar = 1; spawnThread(myThread); sleep(-1); } main() executes on processor 1 (P1), while myThread() executes on P2. Initially, sharedVar exists in the caches of both P1 and P2 with the initial value of 0 (due to some "warm-up code" that isn't shown above.) Question Strictly speaking – preferably without assuming any particular CPU – is myThread() guaranteed to print 1? With my newfound knowledge of processor caches, it seems entirely possible that at the time of the print() statement, P2 may not have received the invalidation request for sharedVar caused by P1's assignment in main(). Therefore, it seems possible that myThread() could print 0. References These are the related articles and books I've been reading. (It wouldn't allow me to format these as links because I'm a new user - sorry.) Shared Memory Consistency Models: A Tutorial hpl.hp.com/techreports/Compaq-DEC/WRL-95-7.pdf Memory Barriers: a Hardware View for Software Hackers rdrop.com/users/paulmck/scalability/paper/whymb.2009.04.05a.pdf Linux Kernel Memory Barriers kernel.org/doc/Documentation/memory-barriers.txt Computer Architecture: A Quantitative Approach amazon.com/Computer-Architecture-Quantitative-Approach-4th/dp/0123704901/ref=dp_ob_title_bk

    Read the article

  • Is this ruby code thread safe?

    - by Ben K.
    Is this code threadsafe? It seems like it should be, because @myvar will never be assigned from multiple threads (assuming block completes in < 1s). But do I need to be worried about a situation where the second block is trying to read @myvar as it's being written? require 'rubygems' require 'eventmachine' @myvar = Time.now.to_i EventMachine.run do EventMachine.add_periodic_timer(1) do EventMachine.defer do @myvar = Time.now.to_i # some calculation and reassign end end EventMachine.add_periodic_timer(0.5) do puts @myvar end end

    Read the article

  • How do I make a background thread in Java that allows the main application to exit completely? This

    - by Bob
    I have a Java application that creates a new thread to do some work. I can launch the new thread with no problems. When the "main" program terminates, I want the thread I created to keep running - which it does... But the problem is, when I run the main application from Eclipse or from Ant under Windows, control doesn't return unless the background process is killed. If I fork the main java process in ant, I want control to return to ant once the main thread is done with its work... But as it is, ant continues to wait until both the main process and the created thread are both terminated. How do I launch the thread in the background such that control will return to ant when the "main" application is finished? (By the way, when I run the same application under Linux, I am able to do this with no problems).

    Read the article

  • Java Thread - Memory consistency errors

    - by Yatendra Goel
    I was reading a Sun's tutorial on Concurrency. But I couldn't understand exactly what memory consistency errors are? I googled about that but didn't find any helpful tutorial or article about that. I know that this question is a subjective one, so you can provide me links to articles on the above topic. It would be great if you explain it with a simple example.

    Read the article

  • ID generator with local static variable - thread-safe?

    - by Poseidon
    Will the following piece of code work as expected in a multi-threaded scenario? int getUniqueID() { static int ID=0; return ++ID; } It's not necessary that the IDs to be contiguous - even if it skips a value, it's fine. Can it be said that when this function returns, the value returned will be unique across all threads?

    Read the article

  • Nagios "CRITICAL - Socket timeout after 10 seconds" problems with service and host Checks.

    - by Kristiaan
    Hi Everyone, got a little bit of a problem with a Nagios system we are using in our office, which has only recently started appearing. what i would like to know really is the best solution to resolve this problem as ive done a bit of reading on it and there seems to be lots of different ways to solve it.. basically at random points throughout the day and on random hosts / services we will get a Critical warning flagged up that something is not behaving as it should, when we investigate 9 times out of 10 we end up with this as an error message. "SERVICE ALERT: SERVERNAME ;NSClient++ Version;CRITICAL;SOFT;1;CRITICAL - Socket timeout after 10 seconds" indicating the service or host has timed out, where do i go about setting the timeouts so this stops ? ive read that some of the plugin timesouts are as low as 10 seconds... thanks Kris

    Read the article

  • juju spends bootstrap-timeout with a final message it cannot find /var/lib/juju/nonce.txt

    - by user285199
    I build two VMware's machines. First one with MAAS, second one with a fresh installation from MAAS. Region controller was installed with Ubuntu 12.04 distribution, and upgraded (. Node computing was installed from MAAS with Quantal 12.10. Juju was installed and upgraded to 1.18 (from ppa:juju/stable repository). MAAS was upgraded from cloud-archive:tools repository. In debug mode, I got how Juju connects to node. Then I run the same instruction: ssh -o "StrictHostKeyChecking no" -o "PasswordAuthentication no" -i /home/lliurex/.juju/ssh/juju_id_rsa -i /home/lliurex/.ssh/id_rsa [email protected] /bin/bash It worked (with and without /bin/bash). When Juju spends all bootstrap-timeout tells it has not found /var/lib/juju/nonce.txt file. It's true, it doesn't exist. It doesn't mind if you put a timeout of 1800, 3600 or 72000, it always finishes the same.

    Read the article

  • First Foray&ndash;About timeout

    - by SQLMonger
    It has been quite a while since I signed up for this blog site and high time that something was posted.  I have a list of topics that I will be working through and posting.  Some I am sure will have been posted by others, but I will be sticking to the technical problems and challenges that I’ve recently faced, and the solutions that worked for me.  My motto when learning something new has always been “My kingdom for an example!”, and I plan on delivering useful examples here so others can learn from my efforts, failures and successes.   A bit of background about me… My name is Clayton Groom. I am a founding partner of a consulting firm in St. Louis Missouri, Covenant Technology Partners, LLC and focus on SQL Server Data Warehouse design, Analysis Services and Enterprise Reporting solutions.  I have been working with SQL Server since the early nineties, when it still only ran on OS/2. I love solving puzzles and technical challenges.   Enough about me… On to a real problem… SSIS Connection Time outs versus Command Time outs Last week, I was working on automating the processing for a large Analysis Services cube.  I had reworked an SSIS package and script task originally posted by Vidas Matelis that automates the process of adding new and dropping old partitions to/from an Analysis Services cube.  I had the package working great, tested, and ready for deployment.  It basically performs a query against the source system to determine if there is new data in the warehouse that will require a new partition to be added to the cube, and it checks the cube to see if there are any partitions that are present that are no longer needed in a rolling 60 month window. My client uses Tivoli for running all their production jobs, and not SQL Agent, so I had to build a command line file for Tivoli to use to run the package. Everything was going great. I had tested the command file from my development workstation using an XML configuration file to pass in server-specific parameters into the package when executed using the DTExec utility. With all the pieces ready, I updated the dtsconfig file to point to the UAT environment and started working with the Tivoli developer to test the job.  On the first run, the job failed, and from what I could see in the SSIS log, it had failed because of a timeout. Other errors in the log made me think that perhaps the connection string had not been passed into the package correctly. We bumped the Connection Manager  timeout values from 20 seconds to 120 seconds and tried again. The job still failed. After changing the command line to use the /SET option instead of the /CONFIGFILE option, we tested again, and again failure. After a number more failed attempts, and getting the Teradata DBA involved to monitor and see if we were connecting and failing or just failing to connect, we determined that the job was indeed connecting to the server and then disconnecting itself after 30 seconds.  This seemed odd, as we had the timeout values for the connection manager set to 180 seconds by then.  At this point one of the DBA’s found a post on the Teradata forum that had the clues to the puzzle: There is a separate “CommandTimeout” custom property on the Data source object that may needed to be adjusted for longer running queries.  I opened up the SSIS package, opened the data flow task that generated the partition list table and right-clicked on the data source. from the context menu, I selected “Show Advanced Editor” and found the property. Sure enough, it was set to 30 seconds. The CommandTimeout property can also be edited in the SSIS Properties sheet. In order to determine how long the timeout needed to be, I ran the query from the task in the development environment and received a response in a matter of seconds.  I then tried the same query against the production database and waited several minutes for a response. This did not seem to be a reasonable response time for the query involved, and indeed it wasn’t. The Teradata DBA’s adjusted the query governor settings for the service account I was testing with, and we were able to get the response back down under a minute.  Still, I set the CommandTimeout property to a much higher value in case the job was ever started during a time of high-demand on the production server. With this change in place, the job finally completed successfully.  The lesson learned for me was two-fold: Always compare query execution times between development and production environments, and don’t assume that production will always be faster.  With higher user demands, query governors, and a whole lot more data, the execution time of even what might seem to be simple queries can vary greatly. SSIS Connection time out settings do not affect command time outs.  Connection timeouts control how long the package will wait for a response from the server before assuming the server is not available or is not responding. Command time outs control how long a task will wait for results to start being returned before deciding that the server is not responding. Both lessons seem pretty straight forward, and I felt pretty sheepish once I finally figured out what the issue was.  To be fair though, In the 5+ years that I have been working with SSIS, I could only recall one other time where I had to set the CommandTimeout property, and that memory only resurfaced while I was penning this post.

    Read the article

  • Thread safe GUI programming

    - by James
    I have been programming Java with swing for a couple of years now, and always accepted that GUI interactions had to happen on the Event Dispatch Thread. I recently started to use GTK+ for C applications and was unsurprised to find that GUI interactions had to be called on gtk_main. Similarly, I looked at SWT to see in what ways it was different to Swing and to see if it was worth using, and again found the UI thread idea, and I am sure that these 3 are not the only toolkits to use this model. I was wondering if there is a reason for this design i.e. what is the reason for keeping UI modifications isolated to a single thread. I can see why some modifications may cause issues (like modifying a list while it is being drawn), but I do not see why these concerns pass on to the user of the API. Is there a limit imposed by an operating system? Is there a good reason these concerns are not 'hidden' (i.e. some form of synchronization that is invisible to the user)? Is there any (even purely conceptual) way of creating a thread safe graphics library, or is such a thing actually impossible? I found this http://blogs.operationaldynamics.com/andrew/software/gnome-desktop/gtk-thread-awareness which seems to describe GTK differently to how I understood it (although my understanding was the same as many people's) How does this differ to other toolkits? Is it possible to implement this in Swing (as the EDT model does not actually prevent access from other threads, it just often leads to Exceptions)

    Read the article

  • Logic / Render phases with a single thread

    - by DevilWithin
    The question I have may generate different opinions from different developers, but I'd still like to have an answer on this. Its all about the updating and rendering steps of the game loop, and their use under multi and single threaded environments. Currently, there is one thread running, which takes care of sequentially executing events , logic and rendering. Sometimes, the logic part may wish to change the game state to something else, and in between do some loading of files. The result is that the game hangs completely while loading, and then proceeds to normal rendering of the new state. To go around this, i could make another thread, do the loading there while the main thread renders a smooth loading animation, and then proceed normally. The real question is about if i don't create another thread. I could refresh the screen from the logic thread, and provide some basic loading screen, which could be not so smoothly updated while the files load. In fact, this approach is not loved by a lot of developers, as it scrambles render code in the logic step, which may cause problems of different sorts.. Hope its clear!

    Read the article

  • How to do thread management in C++?

    - by Dipan Mehta
    We use pthread for thread management in C based systems. pthread is in general compilable by C++ compiler (like g++). However, what are the better ways of abstractions for threads in C++? Also, for making any system to be working in a multi-threaded system, it is also important to make thread safe. What are the standard libraries that requires alternative (installs) to be thread safe or are they unsafe for multi-threaded environments? Is smart pointers, templates require special measures to make it safe? What are the best practices for the thread managements in C++?

    Read the article

  • svn-based versioning tool, problem with network timeout

    - by Scarlet
    My dev team was committed a versioning tool based on Subversion to run on Windows (our svn client is sliksvn). We're developing with Delphi XE2, should that matter. We're asked to implement a "check for updates availability" feature, which has to work as follows: Connect to the SVN repo via svn+ssh protocol; See if there are changes to receive and list them; Let the user decide if he wants to receive changes or not. We don't have a great knowledge on svn, so we thought to implement that thing client side by a certain number of CreateProcess calls that wrap directly proper svn commands. Anyways what we perceived is that if network problems should arise, such like a connection drop, svn client hangs forever waiting for the operation to close instead of failing for timeout. We know that CreateProcess can be given a timeout argument, but it wouldn't be correct to use it, as we can't know from outside how long will be the svn operation taking to complete. Is there any way to avoid that deadlock?

    Read the article

  • How can I measure TCP timeout limit on NAT firewall for setting keepalive interval?

    - by jmanning2k
    A new (NAT) firewall appliance was recently installed at $WORK. Since then, I'm getting many network timeouts and interruptions, especially for operations which would require the server to think for a bit without a response (svn update, rsync, etc.). Inbound SSH sessions over VPN also timeout frequently. That clearly suggests I need to adjust the TCP (and ssh) keepalive time on the servers in question in order to reduce these errors. But what is the appropriate value I should use? Assuming I have machines on both sides of the firewall between which I can make a connection, is there a way to measure what the time limit on TCP connections might be for this firewall? In theory, I would send a packet with gradually increasing intervals until the connection is lost. Any tools that might help (free or open source would be best, but I'm open to other suggestions)? The appliance is not under my control, so I can't just get the value, though I am attempting to ask what it currently is and if I can get it increased.

    Read the article

  • Intermittent timeout when connecting to Sql Server, what do I look for?

    - by Will
    Sql Server 2008 Standard 64bit on Windows Server 2008 R2 virtual machine hosted on a Hyper-V server. I'm getting intermittent timeouts when connecting to the server. This happens for both windows and Sql Authentication. May timeout every 2 out of 5 tries in different applications. When the connection times out, I can see (in Profiler) that no connection was made. Firewall is holey, server port is static (good ol' 1433). If I ping /t the server I get a steady connection that wavers between 1 and 2 ms. Any ideas what else to try would be appreciated, thanks.

    Read the article

  • Multithreaded game fails on SwapBuffers in render thread at exit

    - by user782220
    The render loop and windows message loop run on separate threads. The way the program exits is that after PostQuitMessage is called in WM_DESTROY the message loop thread signals the render loop thread to exit. As far as I can tell before the render loop thread can even process the signal it tries SwapBuffers and that fails. My question, is there something about how Windows processes WM_DESTROY and WM_QUIT, in maybe DefWindowProc that causes various objects associated with rendering to go away even though I haven't explicitly deleted anything? And that would explain why the rendering thread is making bad calls at exit?

    Read the article

  • Relation between TCP/IP Keep Alive and HTTP Keep Alive timeout values

    - by Suresh Kumar
    I am trying to understand the relation between TCP/IP and HTTP timeout values. Are these two timeout values different or same? Most Web servers allow users to set the HTTP Keep Alive timeout value through some configuration. How is this value used by the Web servers? is this value just set on the underlying TCP/IP socket i.e is the HTTP Keep Alive timeout and TCP/IP Keep Alive Timeout same? or are they treated differently? My understanding is (maybe incorrect): The Web server uses the default timeout on the underlying TCP socket (i.e. indefinite) and creates Worker thread that counts down the specified HTTP timeout interval. When the Worker thread hits zero, it closes the connection.

    Read the article

  • How to add a timeout value when using Java's Runtime.exec()?

    - by James Adams
    I have a method I am using to execute a command on the local host. I'd like to add a timeout parameter to the method so that if the command being called doesn't finish in a reasonable amount of time the method will return with an error code. Here's what it looks like so far, without the ability to timeout: public static int executeCommandLine(final String commandLine, final boolean printOutput, final boolean printError) throws IOException, InterruptedException { Runtime runtime = Runtime.getRuntime(); Process process = runtime.exec(commandLine); if (printOutput) { BufferedReader outputReader = new BufferedReader(new InputStreamReader(process.getInputStream())); System.out.println("Output: " + outputReader.readLine()); } if (printError) { BufferedReader errorReader = new BufferedReader(new InputStreamReader(process.getErrorStream())); System.out.println("Error: " + errorReader.readLine()); } return process.waitFor(); } Can anyone suggest a good way for me to implement a timeout parameter? Thanks in advance for any suggestions! --James

    Read the article

  • What does "infinity" really mean on a connection timeout? Does it retry the connection?

    - by corgrath
    The difference between connection and read timeout, is that read specifies how long the data connection can be open until it automatically closesc, correct? A connection timeout specifies how long the socket should wait until a connection is established, correct? So if a connection timeout is set to "infinity" what does that really mean? Will it try to establish a connection and if no response is given (as on packets are lost? or port is down?) it will just idle? or will Could someone please explain the basics of network/socket timeouts? and in what situation can a client socket wait infinity?

    Read the article

< Previous Page | 12 13 14 15 16 17 18 19 20 21 22 23  | Next Page >