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From: Ingo Molnar <mingo@elte.hu>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	Marcin Slusarz <marcin.slusarz@gmail.com>,
	Don Zickus <dzickus@redhat.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 10:39:36 +0200	[thread overview]
Message-ID: <20110518083936.GF14805@elte.hu> (raw)
In-Reply-To: <20110518034431.GC11023@google.com>


* 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.

Thanks,

	Ingo

  reply	other threads:[~2011-05-18  8:39 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 [this message]
2011-05-18 13:51         ` Don Zickus
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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