Date: Sun, 29 Jan 2012 11:35:42 +0100 From: Peter Holm <peter@holm.cc> To: Attilio Rao <attilio@freebsd.org> Cc: freebsd-hackers@freebsd.org, Florian Smeets <flo@smeets.im>, Ryan Stone <rysto32@gmail.com> Subject: Re: Kernel threads inherit CPU affinity from random sibling Message-ID: <20120129103542.GA18535@x2.osted.lan> In-Reply-To: <CAJ-FndC1WHMyAXbT-rW=Ar%2BpspiwW%2B8cBF3OV4gMJssaO4UPUg@mail.gmail.com> References: <CAFMmRNxF1uMOr39BbZkpPN=uM7G09dtcckAYw8ag6n6bi=FeOw@mail.gmail.com> <CAJ-FndDHsQRRNmrS7fsELEVohozWvvfaZ6eW_GipwHdjU9ZwxA@mail.gmail.com> <CAFMmRNyPkwx3hRtraq6QL64kibAeV3W23FE34T1oDnf9SVFOYg@mail.gmail.com> <CAJ-FndD3366-uT191jMva3P-uL0DHi6nFeRfdsKA1hbJW7WqEA@mail.gmail.com> <CAJ-FndC1WHMyAXbT-rW=Ar%2BpspiwW%2B8cBF3OV4gMJssaO4UPUg@mail.gmail.com>
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On Sat, Jan 28, 2012 at 02:39:17PM +0100, Attilio Rao wrote: > 2012/1/28 Attilio Rao <attilio@freebsd.org>: > > 2012/1/28 Ryan Stone <rysto32@gmail.com>: > >> On Fri, Jan 27, 2012 at 10:41 PM, Attilio Rao <attilio@freebsd.org> wrote: > >>> I think what you found out is very sensitive. > >>> However, the patch is not correct as you cannot call > >>> cpuset_setthread() with thread_lock held. > >> > >> Whoops! I actually discovered that for myself and had already fixed > >> it, but apparently I included an old version of the patch in the > >> email. > >> > >>> Hence this is my fix: > >>> http://www.freebsd.org/~attilio/cpuset_root.patch > >> > >> Oh, I do like this better. I tried something similar myself but > >> abandoned it because I misread how sched_affinity() was implemented by > >> 4BSD(I had gotten the impression that once TSF_AFFINITY is set it > >> could never be cleared). > > > > Do you have a pathological test-case for it? Are you going to test the patch? > > BTW, I've just now updated the patch in order to remove an added white > line and s/priority/affinity in comments. > I've tested this patch with what I got of threaded test scenarios, for 14 hours without finding any issues. - Peter
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