From: Ingo Molnar <mingo@elte.hu>
To: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org
Subject: Re: Scheduler regression: Too frequent timer interrupts(?)
Date: Fri, 17 Apr 2009 17:35:20 +0200 [thread overview]
Message-ID: <20090417153520.GA29968@elte.hu> (raw)
In-Reply-To: <alpine.DEB.1.10.0904171100510.21575@qirst.com>
* Christoph Lameter <cl@linux.com> wrote:
> On Fri, 17 Apr 2009, Peter Zijlstra wrote:
>
> > And a random 1us cutoff, is well, random.
>
> Its got to be somewhere.
Sorry, that's not a rational answer that makes any sense.
Peter's point is statistics 101: please show absolute values not an
event distribution cutoff - how much total time do we spend in the
kernel in that workload?
Is the overhead 1%? 2%? 0.5%? And how did it change from 2.6.22
onwards? Did it go up by 0.1%, from 1% to 1.1%? Or did the average
go down by 0.05%, while increasing the spread of events (thus
fooling your cutoff)?
These are very simple, very basic, very straightforward questions -
and no straight answer was forthcoming from you. Are you not
interested in that answer?
Ingo
next prev parent reply other threads:[~2009-04-17 15:35 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
2009-04-28 21:21 ` Christoph Lameter
2009-04-17 15:35 ` Ingo Molnar [this message]
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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