Subject: Re: 2.6.20-rc6-mm3
From: Thomas Gleixner <tglx@linutronix.de>
To: dwalker@mvista.com
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org, mingo@elte.hu
In-Reply-To: <1170791739.3455.3.camel@dwalker1>
References: <20070129204528.eb8d695e.akpm@osdl.org>
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	 <1170791739.3455.3.camel@dwalker1>
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Date: Tue, 06 Feb 2007 21:20:06 +0100
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On Tue, 2007-02-06 at 11:55 -0800, Daniel Walker wrote:
> > What kind of artificial problem are you creating here ?
>
> I'm not trying to create anything .. However, as I said before
> the /proc/interrupts "timer" entry doesn't work the same as it has in
> other kernels.

Yes, it is different. Why are you insisting, that something is a problem
just because it is different ?

> If you think that isn't a problem then explain why ..

Simply because it works and it does not make any sense to have a per cpu
timer (lapic) and the PIT firing at the same periodic interval. PIT does
nothing else than jiffies64++. The clockevents code just optimizes that
away and lets one cpu do the jiffies64++ in its periodic per cpu
interrupt.

So where is the problem ?

> > > We could just remove the timer entry .
> > 
> > No we can't. The timer interrupt is setup and it does not go away, as we
> > keep the PIT as a backup for the broken lapics.
> 
> Ok, how about adding the interrupts to the list which are driving the
> timer ?

Uurg. /proc/interrupts has nothing to do with timers. It's interrupts
statistics. See LOC entry for the lapic ones.

	tglx


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