Re: [Mingw-w64-public] winpthreads, pthread_setschedparam, and detached threads
It's not clear to me from this explanation why this code should fail: pthread_setschedparam(pthread_self(), SCHED_OTHER, ¶m); but in winpthreads, for a detached thread, it will. > Re: [Mingw-w64-public] winpthreads, pthread_setschedparam, and detached > threads > From: lh mouse - 2016-06-01 03:31:43 > Note that in most cases threads other than the one calling `pthread_detach()` > can terminate at anytime. After a call `pthread_detach()`, if the thread > terminates, its resources are freed automatically, rendering the `pthread_t` > no longer valid. It is impossible to tell whether a `pthread_t` is > designating a thread that has terminated. It may even be designating a thread > that is different from the one the user expects because thread IDs > can be reused. > By calling `pthread_detach()` on a `pthread_t` you _semantically_ > destroy/close it and should not use it any more. -- Best regards, lh_mouse 2016-06-01 - 发件人："Burkhardt, Glenn BUTAS" 发送日期：2016-05-31 23:11 收件人：mingw-w64-public@... 抄送： 主题：[Mingw-w64-public] winpthreads, pthread_setschedparam, and detached threads The way the winpthreads code is writing, the Windows handle for the thread is cleared when the thread is made detached. That means that the pthread_setschedparam() call can't work. So thread priorities for detached threads can only be set once, at thread creation, before the thread is detached, or as part of the pthread_create() call. Is there a reason for this? For me, it's unexpected behavior. -- What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e ___ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
Re: [Mingw-w64-public] winpthreads, pthread_setschedparam, and detached threads
I think it would be a bug in your example. Were it not a bug there would be no way for a detached thread to operate itself. -- Best regards, lh_mouse 2016-06-01 - 发件人："Burkhardt, Glenn BUTAS" 发送日期：2016-06-01 21:25 收件人：mingw-w64-public@lists.sourceforge.net 抄送： 主题：Re: [Mingw-w64-public] winpthreads, pthread_setschedparam, and detached threads It's not clear to me from this explanation why this code should fail: pthread_setschedparam(pthread_self(), SCHED_OTHER, ¶m); but in winpthreads, for a detached thread, it will. > Re: [Mingw-w64-public] winpthreads, pthread_setschedparam, and detached > threads > From: lh mouse - 2016-06-01 03:31:43 > Note that in most cases threads other than the one calling `pthread_detach()` > can terminate at anytime. After a call `pthread_detach()`, if the thread > terminates, its resources are freed automatically, rendering the `pthread_t` > no longer valid. It is impossible to tell whether a `pthread_t` is > designating a thread that has terminated. It may even be designating a thread > that is different from the one the user expects because thread IDs > can be reused. > By calling `pthread_detach()` on a `pthread_t` you _semantically_ > destroy/close it and should not use it any more. -- Best regards, lh_mouse 2016-06-01 - 发件人："Burkhardt, Glenn BUTAS" 发送日期：2016-05-31 23:11 收件人：mingw-w64-public@... 抄送： 主题：[Mingw-w64-public] winpthreads, pthread_setschedparam, and detached threads The way the winpthreads code is writing, the Windows handle for the thread is cleared when the thread is made detached. That means that the pthread_setschedparam() call can't work. So thread priorities for detached threads can only be set once, at thread creation, before the thread is detached, or as part of the pthread_create() call. Is there a reason for this? For me, it's unexpected behavior. -- What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e ___ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
Re: [Mingw-w64-public] winpthreads, pthread_setschedparam, and detached threads
Hello Lefty! On Tue, May 31, 2016 at 11:31 PM, lh mouse wrote: > Note that in most cases threads other than the one calling `pthread_detach()` > can terminate at anytime. > ... I would say your description fits the typical use case. > By calling `pthread_detach()` on a `pthread_t` you _semantically_ > destroy/close it and should not use it any more. Well, maybe. I certainly don't find anything in the pthread standard that justifies this semantic interpretation (nor that contradicts it). I do expect that many people look at it the way you do. One can certainly imagine a use case where "using" a detached thread (and calling pthread_setschedparam() on it) would make sense. Detached threads still respect synchronization objects (e.g., mutexes and condition variable, but not pthread_join). So maybe you have a detached thread servicing some sort of queue (controlled by a condition variable) and you want to throttle it by changing its priority, so you want to call pthread_setschedparam() on it. Of course, you can easily work around this issue by not detaching the thread. > > Best regards, > lh_mouse > 2016-06-01 Happy Hacking! > 发件人："Burkhardt, Glenn BUTAS" > ... > 主题：[Mingw-w64-public] winpthreads, pthread_setschedparam, > and detached threads > > The way the winpthreads code is writing, the Windows handle for the thread is > cleared when the thread is made detached. That means that the > pthread_setschedparam() call can't work. So thread priorities for detached > threads can only be set once, at thread creation, before the thread is > detached, or as part of the pthread_create() call. > ... -- What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e ___ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
