From: Peter Zijlstra <peterz@infradead.org>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: Don Zickus <dzickus@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Michal Hocko <mhocko@suse.cz>
Subject: Re: [PATCH] watchdog: Make sure the watchdog thread gets CPU on loaded system
Date: Thu, 15 Mar 2012 17:16:43 +0100 [thread overview]
Message-ID: <1331828203.18960.200.camel@twins> (raw)
In-Reply-To: <1331827890.18960.198.camel@twins>
On Thu, 2012-03-15 at 17:11 +0100, Peter Zijlstra wrote:
> On Thu, 2012-03-15 at 17:10 +0100, Peter Zijlstra wrote:
> > On Thu, 2012-03-15 at 08:39 -0700, Mandeep Singh Baines wrote:
> > > Its a good tool for catching problems of scale. As we move to more and
> > > more cores you'll uncover bugs where data structures start to blow up.
> > > Hash tables get huge, when you have 100000s of processes or millions
> > > of
> > > TCP flows, or cgroups or namespace. That critical section (spinlock,
> > > spinlock_bh, or preempt_disable) that used to be OK might no longer
> > > be.
> >
> > Or you run with the preempt latency tracer.
>
> Or for that matter run cyclictest...
Thing is, if you want a latency detector, call it that and stop
pretending its a useful debug feature. Also, if you want that, set the
interval in the 0.1-0.5 seconds range and dump stack on every new max.
next prev parent reply other threads:[~2012-03-15 16:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-14 20:38 [PATCH] watchdog: Make sure the watchdog thread gets CPU on loaded system Don Zickus
2012-03-14 20:59 ` Mandeep Singh Baines
2012-03-14 23:19 ` Andrew Morton
2012-03-15 1:45 ` Mandeep Singh Baines
2012-03-15 11:00 ` Peter Zijlstra
2012-03-15 11:06 ` Peter Zijlstra
2012-03-15 12:42 ` Ingo Molnar
2012-03-15 14:00 ` Peter Zijlstra
2012-03-15 14:35 ` Don Zickus
2012-03-15 15:39 ` Mandeep Singh Baines
2012-03-15 16:10 ` Peter Zijlstra
2012-03-15 16:11 ` Peter Zijlstra
2012-03-15 16:16 ` Peter Zijlstra [this message]
2012-03-15 17:04 ` Mandeep Singh Baines
2012-03-15 8:02 ` Michal Hocko
2012-03-15 15:54 ` Don Zickus
2012-03-15 16:04 ` Peter Zijlstra
2012-03-19 22:00 ` Andrew Morton
2012-03-15 16:14 ` Michal Hocko
2012-03-15 17:14 ` Don Zickus
-- strict thread matches above, loose matches on Subject: below --
2012-03-13 9:45 [PATCH] watchdog: make " Michal Hocko
2012-03-13 13:42 ` Don Zickus
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