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From: Pavel Machek <pavel@suse.cz>
To: Lee Revell <rlrevell@joe-job.com>
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
Subject: Re: [discuss] Re: [PATCH] adjust x86-64 watchdog tick calculation
Date: Sat, 14 May 2005 01:21:22 +0200	[thread overview]
Message-ID: <20050513232122.GD2016@elf.ucw.cz> (raw)
In-Reply-To: <1116024993.6380.47.camel@mindpipe>

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.

I do not think so.

In may be "worth fixing", but no, that does not mean you should stick
"if ints_disabled > 1msec panic()" into code. That would make most
systems unusable.

Think pio-only disks, for example. Think serial console.
									Pavel
-- 
Boycott Kodak -- for their patent abuse against Java.

  reply	other threads:[~2005-05-13 23:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-05-12  8:27 [PATCH] adjust x86-64 watchdog tick calculation Jan Beulich
2005-05-12 10:00 ` Alexander Nyberg
2005-05-12 11:46   ` [discuss] " Andi Kleen
2005-05-12 14:29   ` Pavel Machek
2005-05-13 11:30     ` Andi Kleen
2005-05-13 19:52       ` Pavel Machek
2005-05-13 21:27         ` Lee Revell
2005-05-13 22:51           ` Pavel Machek
2005-05-13 22:56             ` Lee Revell
2005-05-13 23:21               ` Pavel Machek [this message]
2005-05-13 23:29               ` Dave Jones
2005-05-15 10:52               ` Andi Kleen
2005-05-15 10:36         ` Andi Kleen
2005-05-15 10:51           ` Pavel Machek
2005-05-15 10:54             ` Andi Kleen

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