Subject: Re: [discuss] Re: [PATCH] adjust x86-64 watchdog tick calculation
From: Lee Revell <rlrevell@joe-job.com>
To: Pavel Machek <pavel@suse.cz>
Cc: Andi Kleen <ak@suse.de>, Alexander Nyberg <alexn@telia.com>,
       Jan Beulich <JBeulich@novell.com>, discuss@x86-64.org,
       linux-kernel@vger.kernel.org
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Date: Fri, 13 May 2005 18:56:33 -0400
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On Sat, 2005-05-14 at 00:51 +0200, Pavel Machek wrote:
> Hi!
> 
> > > > > Because it kills machine when interrupt latency gets too high?
> > > > > Like reading battery status using i2c...
> > > > 
> > > > That's a bug in the I2C reader then. Don't shot the messenger for bad news.
> > > 
> > > Disagreed.
> > > 
> > > Linux is not real time OS. Perhaps some real-time constraints "may not
> > > spend > 100msec with interrupts disabled" would be healthy
> >              ^^^^
> > You mean "microseconds", right?  100ms will be perceived by the user as,
> > well, their machine freezing for 100ms...
> 
> I did mean miliseconds. IIRC current watchdog is at one second and it
> still triggers even in cases when operation just takes too long.

I thought there was an understanding that 1 ms would be the target for
desktop responsiveness.  So yes, disabling interrupts for more than 1ms
is considered a bug.

Why do you need to disable interrupts for 100ms to read the battery
status exactly?

Lee

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