https://svn.boost.org/trac10/ticket/479 <pre class="wiki">Hi, I am writing a largely multithreaded linux program (20-60 threads) on version Fedora Core 2. I am using glib c version 2.3.3-27. In addition, I am using the boost libraries (version 1.32.0) for my threading and locking. Specifically, I am using mutexes, recursive_mutexes, scoped locking, and conditions. My problem is that the process will suddenly cease activity for random lengths of time (1 sec to minutes). However, it never crashes or produces incorrect results. Also, I do not think that it is deadlocking because it always resumes its activity. I have done some profiling of the locks, and it shows very strange behavior. For instance, threads will block for long lengths of time (the length of the inactivity) while no thread is holding the corresponding mutex more than fractions of a second. When I explored this further, it appears that thread A is blocking on a mutex while thread B holds it. I am using boost::recursive_mutex::scoped_lock objects for the locking. The weird thing is that thread B pauses at the very end of the lock's scope (again for a the length of inactivity), as though the attempt to unlock the mutex is not waking thread A and descheduling thread B for a long time. I created a test program that spawns 30 threads that just do a bunch of locking of these boost scoped locks and yielding. This program, too, shows the same downtime activity (again without crashing or deadlocking), though less frequently (I suspect because the locking pattern is probably different than in my program). It also always resumes its activity eventually. I have attached the test program code. I'm not sure whether this is a problem with the boost libraries or a linux problem, or my own problem. I was wondering if anyone has experienced similar behavior and might be able to offer some insight or guidance. Thanks! Matt </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/479 Trac 1.4.3 Roland Schwarz Thu, 28 Dec 2006 15:37:28 GMT https://svn.boost.org/trac10/ticket/479#comment:1 https://svn.boost.org/trac10/ticket/479#comment:1 <ul> <li><strong>status</strong> <span class="trac-field-old">assigned</span> → <span class="trac-field-new">closed</span> </li> </ul> <pre class="wiki">Logged In: YES user_id=541730 Originator: NO Don't know if the "problem" has been resolved, however I was not able to reproduce the described behaviour. The submitted code also does not clearly show what is going wrong. I tested the code on linux and windows, and it gave comparable results. The code however does run _very_ long. I compared this to a loop which only locked/unlocked and calculated i*i+1 like the example. This run for 95 minutes. If the question is still open, please try to be more specific. Regards Roland </pre> Ticket