Date: Wed, 26 Aug 2009 16:42:59 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: Linda Messerschmidt <linda.messerschmidt@gmail.com> Subject: Re: Intermittent system hangs on 7.2-RELEASE-p1 Message-ID: <200908261642.59419.jhb@freebsd.org> In-Reply-To: <237c27100908261203g7e771400o2d9603220d1f1e0b@mail.gmail.com> References: <237c27100908261203g7e771400o2d9603220d1f1e0b@mail.gmail.com>
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On Wednesday 26 August 2009 3:03:13 pm Linda Messerschmidt wrote: > I'm trying to troubleshoot an intermittent Apache performance problem, > and I've narrowed it down using to what appears to be a brief > whole-system hang that last from 0.5 - 3 seconds. They occur every > few minutes. 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, so in theory if your machine was livelocked temporarily that might explain this. -- John Baldwin
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