Date: Fri, 9 Jul 2004 13:15:16 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: Taku YAMAMOTO <taku@tackymt.homeip.net> Subject: Re: Native preemption is the culprit [was Re: today's CURRENT lockups] Message-ID: <200407091315.16899.jhb@FreeBSD.org> In-Reply-To: <20040709111955.2901ce5b.taku@tackymt.homeip.net> References: <20040705184940.GA2651@tybalt.greiner.local> <200407081317.53981.jhb@FreeBSD.org> <20040709111955.2901ce5b.taku@tackymt.homeip.net>
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On Thursday 08 July 2004 10:19 pm, Taku YAMAMOTO wrote: > On Thu, 8 Jul 2004 13:17:53 -0400 > > John Baldwin <jhb@FreeBSD.org> wrote: > > On Thursday 08 July 2004 09:21 am, Taku YAMAMOTO wrote: > > > greetings, > > > > > > > > > A quick glance showed me that there are some interesting code paths in > > > sched_ule.c that can be problematic in SMP case. > > > > > > 1. sched_choose() => kseq_idled() => sched_add() > > > 2. sched_choose() => kseq_assign() => sched_add() > > > 3. sched_runnable() => kseq_assign() => sched_add() > > > > > > Here is the patch that re-enables preemption except for the above three > > > cases. > > > > This looks correct. I'll test it locally first. Has it worked for you > > all day? > > My machine (HTT) has been up for 20 hours without a hang since last update. > I tried to stress it in various ways (fsck -n, buildworld & buildkernel in > parallel, burning a CD, etc.) but failed to crash it. > > I'm bit afraid since the code is not tested on real SMP machines. > How is it going on yours? My test machine is not a true SMP machine either, just HTT. It has been running a -j 256 worldloop overnight with no problems, so I committed a slightly modified version of the patch yesterday. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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