Date: Thu, 27 Aug 2009 16:14:39 -0400 From: Linda Messerschmidt <linda.messerschmidt@gmail.com> To: freebsd-hackers@freebsd.org Subject: Re: Intermittent system hangs on 7.2-RELEASE-p1 Message-ID: <237c27100908271314v28e6c710s8a278064333d1d20@mail.gmail.com> In-Reply-To: <200908261642.59419.jhb@freebsd.org> References: <237c27100908261203g7e771400o2d9603220d1f1e0b@mail.gmail.com> <200908261642.59419.jhb@freebsd.org>
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On Wed, Aug 26, 2009 at 4:42 PM, John Baldwin<jhb@freebsd.org> wrote: > One thing to note is that ktrace only logs voluntary context switches (i.e. > call to tsleep or waiting on a condition variable). It specifically does not > log preemptions or blocking on a mutex, I was not aware, thanks. > so in theory if your machine was > livelocked temporarily that might explain this. How would we determine that? We are now able to reproduce this on a test machine, even after slipping in a 7.2-STABLE kernel with KTR enabled. So we have a lot more options now. Unfortunately, I don't really "get" KTR yet. It looks like it has relevant info, but I was unable to correlate its huge timestamps (e.g. 6795522404430562) to ktrace output times (e.g. 1251387606.225544) showing problem areas. What's my best bet from here?
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