From: Peter Zijlstra <peterz@infradead.org>
To: David Miller <davem@davemloft.net>
Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, tglx@linutronix.de,
guichaz@yahoo.fr
Subject: Re: Second soft lockup regression in yesterday's sched.git merge
Date: Wed, 23 Apr 2008 08:51:39 +0200 [thread overview]
Message-ID: <1208933499.7115.324.camel@twins> (raw)
In-Reply-To: <20080422.233935.37053549.davem@davemloft.net>
On Tue, 2008-04-22 at 23:39 -0700, David Miller wrote:
> Two changets after the buggy cpu_clock() changes, we have:
>
> commit 15934a37324f32e0fda633dc7984a671ea81cd75
> Author: Guillaume Chazarain <guichaz@yahoo.fr>
> Date: Sat Apr 19 19:44:57 2008 +0200
>
> sched: fix rq->clock overflows detection with CONFIG_NO_HZ
>
> When using CONFIG_NO_HZ, rq->tick_timestamp is not updated every TICK_NSEC.
> We check that the number of skipped ticks matches the clock jump seen in
> __update_rq_clock().
>
> Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
> Which also causes softlockup warnings on my Niagara systems.
>
> Note this is with the cpu_clock() change reverted, and the
> usual test case kernel build after a delay:
>
> sleep 10m; time make -j64 >build.log 2>&1; make -j64 image
The effect of this one is that it should properly account idle time in
rq->clock when waking from nohz.
This 'extra' idle time would then propagate through cpu_clock() into the
softlockup code.
Could it be we touch the soft watchdog before we correct all these idle
times?
prev parent reply other threads:[~2008-04-23 6:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-23 6:39 Second soft lockup regression in yesterday's sched.git merge David Miller
2008-04-23 6:51 ` Peter Zijlstra [this message]
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