Date: Sun, 2 May 2004 12:57:53 -0400 (EDT) From: Daniel Eischen <eischen@vigrid.com> To: Alexandre Sunny Kovalenko <Alex.Kovalenko@verizon.net> Cc: freebsd-current@freebsd.org Subject: Re: Is it possible to make -lpthread program to use 100% CPU? Message-ID: <Pine.GSO.4.10.10405021253050.4766-100000@pcnet5.pcnet.com> In-Reply-To: <20040502105310.365f91e3.Alex.Kovalenko@verizon.net>
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On Sun, 2 May 2004, Alexandre Sunny Kovalenko wrote: > > I did mention this one ;) With older sources (kern_thread.c 1.175) I have tried > both with the similar results. With the last update (last CTM from EST morning > on Friday 4/30) I only tried _ULE. If you need me to try _4BSD, let me know. > > Just out of curiosity, if I have 64 threads and 4 CPUs would not result be the > same with PTHREAD_SCOPE_SYSTEM and PTHREAD_SCOPE_PROCESS, since I could not > get more KSEGs then I have CPUs, and default is 8 threads per KSEG? Or am I > totally off the mark? You can have more KSEGs than CPUs. The default is one KSEG with N KSEs (where N is the number of CPUs). All scope process threads run in the N KSEs; these threads are not bound to any specific KSE within the KSEG. Scope system threads get their own KSEG and KSE. I don't know how the various schedulers schedule KSEs onto processors. -- Dan Eischen
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