From: Don Zickus <dzickus@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Mandeep Singh Baines <msb@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Marcin Slusarz <marcin.slusarz@gmail.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH 4/4 v2] watchdog: configure nmi watchdog period based on watchdog_thresh
Date: Wed, 18 May 2011 09:51:32 -0400 [thread overview]
Message-ID: <20110518135132.GL29881@redhat.com> (raw)
In-Reply-To: <20110518083936.GF14805@elte.hu>
On Wed, May 18, 2011 at 10:39:36AM +0200, Ingo Molnar wrote:
>
> * Mandeep Singh Baines <msb@chromium.org> wrote:
>
> > Ingo Molnar (mingo@elte.hu) wrote:
> > >
> > > * Mandeep Singh Baines <msb@chromium.org> wrote:
> > >
> > > > Before the conversion of the NMI watchdog to perf event, the watchdog
> > > > timeout was 5 seconds. Now it is 60 seconds. For my particular application,
> > > > netbooks, 5 seconds was a better timeout. With a short timeout, we
> > > > catch faults earlier and are able to send back a panic. With a 60 second
> > > > timeout, the user is unlikely to wait and will instead hit the power
> > > > button, causing us to lose the panic info.
> > >
> > > That's an interesting observation. Have you been able to measure/observe this
> > > effect somehow, or do you presume that users find 60 seconds too long?
> > >
> >
> > Mostly intuition. There is a threshold beyond which the user will hit
> > the power button. Not sure if its 20 seconds or 20 minutes. My feeling
> > was that the 1 minute was too long.
> >
> > For a user experience perspective, a quick reboot also seems like a better
> > experience than a one minute hang. Our systems boot in 8 seconds and restore
> > the previous session so a reboot is almost not noticable.
>
> Indeed you definitely want it configurable and have the delay down to 5 or 10
> seconds, to correlate it with your boot delay.
>
> Personally i consider any hang over 1 second annoying so you might want to work
> on that 8 seconds boot time some more, it's too long ;-)
>
> And any kernel code running with more than 1 second irqs off is a bug, plain
> and simple.
Not necessarily, but in those cases the code can use touch_nmi_watchdog
(for example slow hardware, long print outs, etc). :-)
Cheers,
Don
next prev parent reply other threads:[~2011-05-18 13:52 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-16 23:34 [PATCH 1/4] watchdog: fix rounding issues in get_sample_period() Mandeep Singh Baines
2011-05-16 23:34 ` [PATCH 2/4] watchdog: only disable/enable watchdog if neccessary Mandeep Singh Baines
2011-05-16 23:35 ` [PATCH 3/4] watchdog: disable watchdog when thresh is zero Mandeep Singh Baines
2011-05-17 7:10 ` Ingo Molnar
2011-05-18 3:36 ` [PATCH 3/4 v2] " Mandeep Singh Baines
2011-05-18 8:35 ` Ingo Molnar
2011-05-19 16:20 ` [PATCH 3/4 v3] " Mandeep Singh Baines
2011-05-23 11:13 ` [tip:perf/urgent] watchdog: Disable " tip-bot for Mandeep Singh Baines
2011-05-16 23:35 ` [PATCH 4/4] watchdog: configure nmi watchdog period based on watchdog_thresh Mandeep Singh Baines
2011-05-17 7:16 ` Ingo Molnar
2011-05-17 14:03 ` Don Zickus
2011-05-17 18:47 ` Ingo Molnar
2011-05-18 3:44 ` [PATCH 4/4 v2] " Mandeep Singh Baines
2011-05-18 8:39 ` Ingo Molnar
2011-05-18 13:51 ` Don Zickus [this message]
2011-05-23 11:13 ` [tip:perf/urgent] watchdog: Change the default timeout and " tip-bot for Mandeep Singh Baines
2011-05-24 3:58 ` [tip:perf/urgent] watchdog: Fix non-standard prototype of get_softlockup_thresh() tip-bot for Ingo Molnar
2011-05-18 13:53 ` [PATCH 1/4] watchdog: fix rounding issues in get_sample_period() Don Zickus
2011-05-19 16:26 ` Mandeep Singh Baines
2011-05-20 11:51 ` Ingo Molnar
2011-05-23 5:14 ` Mandeep Singh Baines
2011-06-09 11:47 ` Don Zickus
2011-06-09 14:51 ` Mandeep Singh Baines
2011-05-23 5:10 Mandeep Singh Baines
2011-05-23 5:10 ` [PATCH 2/4] watchdog: only disable/enable watchdog if neccessary Mandeep Singh Baines
2011-05-23 11:12 ` [tip:perf/urgent] watchdog: Only " tip-bot for Mandeep Singh Baines
2011-05-23 5:10 ` [PATCH 3/4] watchdog: disable watchdog when thresh is zero Mandeep Singh Baines
2011-05-23 5:10 ` [PATCH 4/4] watchdog: configure nmi watchdog period based on watchdog_thresh Mandeep Singh Baines
2011-05-23 11:12 ` [tip:perf/urgent] watchdog: Fix rounding bug in get_sample_period() tip-bot for Mandeep Singh Baines
2011-05-24 3:41 linux-next: build warning in Lunus' tree Stephen Rothwell
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