From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Lameter <cl@linux.com>
Cc: Pavel Machek <pavel@ucw.cz>, Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org
Subject: Re: Scheduler regression: Too frequent timer interrupts(?)
Date: Tue, 28 Apr 2009 23:23:16 +0200 [thread overview]
Message-ID: <1240953796.7620.160.camel@twins> (raw)
In-Reply-To: <alpine.DEB.1.10.0904281700220.15947@qirst.com>
On Tue, 2009-04-28 at 17:02 -0400, Christoph Lameter wrote:
> On Thu, 23 Apr 2009, Pavel Machek wrote:
>
> > I'd say that taking interrupt and returning in below 1000nsec is
> > impossible, even on very fast hw.
>
> Hmmm.... Could it be that CONFIG_NO_HZ caused the timer interrupt to be
> avoided in earlier releases? NO_HZ theory at least is to only schedule
> interrupts when necessary. So an interrupt is needed at the end of the
> scheduling intervals and not at HZ frequency.
No, NOHZ only works on idle cpus.
next prev parent reply other threads:[~2009-04-28 21:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-16 19:53 Scheduler regression: Too frequent timer interrupts(?) Christoph Lameter
2009-04-17 7:00 ` Peter Zijlstra
2009-04-17 13:42 ` Christoph Lameter
2009-04-17 14:16 ` Peter Zijlstra
2009-04-17 14:29 ` Christoph Lameter
2009-04-17 14:51 ` Peter Zijlstra
2009-04-17 15:04 ` Christoph Lameter
2009-04-17 15:28 ` Peter Zijlstra
2009-04-23 4:42 ` Pavel Machek
2009-04-28 21:02 ` Christoph Lameter
2009-04-28 21:23 ` Peter Zijlstra [this message]
2009-04-28 21:21 ` Christoph Lameter
2009-04-17 15:35 ` Ingo Molnar
2009-04-17 15:55 ` Christoph Lameter
2009-04-17 16:23 ` Peter Zijlstra
2009-04-17 16:33 ` Christoph Lameter
2009-04-17 16:49 ` Ingo Molnar
2009-04-17 17:19 ` Chris Friesen
2009-04-17 17:45 ` Christoph Lameter
2009-04-17 18:11 ` Peter Zijlstra
2009-04-17 18:20 ` Christoph Lameter
2009-04-17 18:58 ` Peter Zijlstra
2009-04-17 20:34 ` Christoph Lameter
2009-04-17 20:53 ` Peter Zijlstra
2009-04-17 23:24 ` Chris Friesen
2009-04-18 7:35 ` Ingo Molnar
2009-04-18 7:59 ` Andi Kleen
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