From: Peter Zijlstra <peterz@infradead.org>
To: Damien Wyart <damien.wyart@free.fr>
Cc: tmhikaru@gmail.com, Venkatesh Pallipadi <venki@google.com>,
Chase Douglas <chase.douglas@canonical.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, Kyle McMartin <kyle@mcmartin.ca>
Subject: Re: High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later)
Date: Mon, 29 Nov 2010 12:38:46 +0100 [thread overview]
Message-ID: <1291030726.32004.4.camel@laptop> (raw)
In-Reply-To: <20101128114027.GA2745@brouette>
On Sun, 2010-11-28 at 12:40 +0100, Damien Wyart wrote:
> Hi,
>
> * Peter Zijlstra <peterz@infradead.org> [2010-11-27 21:15]:
> > How does this work for you? Its hideous but lets start simple.
> > [...]
>
> Doesn't give wrong numbers like initial bug and tentative patches, but
> feels a bit too slow when numbers go up and down. Correct values are
> reached when waiting long enough, but it feels slow.
>
> As I've tested many combinations, maybe this is an impression because
> I do not remember about "normal" delays for the load to rise and fall,
> but this still feels slow.
You can test this by either booting with nohz=off, or builting with
CONFIG_NO_HZ=n and then comparing the result, something like
make O=defconfig clean; while sleep 10; do uptime >> load.log; done &
make -j32 O=defconfig; kill %1
And comparing the curves between the NO_HZ and !NO_HZ kernels.
I'll try and make the patch less hideous ;-)
next prev parent reply other threads:[~2010-11-29 11:38 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-29 7:01 High CPU load when machine is idle Damien Wyart
2010-10-14 14:58 ` High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later) Damien Wyart
2010-10-14 15:29 ` Chase Douglas
2010-10-14 15:56 ` Damien Wyart
2010-10-15 11:08 ` Peter Zijlstra
2010-10-18 12:32 ` Peter Zijlstra
2010-10-20 13:27 ` Damien Wyart
2010-10-20 13:30 ` Peter Zijlstra
2010-10-20 13:43 ` Peter Zijlstra
2010-10-20 14:14 ` Peter Zijlstra
2010-10-20 14:25 ` Peter Zijlstra
2010-10-20 17:26 ` Peter Zijlstra
2010-10-20 20:24 ` Damien Wyart
2010-10-21 1:48 ` tmhikaru
2010-10-21 1:53 ` tmhikaru
2010-10-21 8:22 ` Ingo Molnar
2010-10-21 8:57 ` tmhikaru
2010-10-21 18:36 ` tmhikaru
2010-10-22 1:37 ` tmhikaru
2010-10-21 12:09 ` Peter Zijlstra
2010-10-21 17:18 ` Venkatesh Pallipadi
2010-10-22 21:03 ` Venkatesh Pallipadi
2010-10-22 23:03 ` High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later) Venkatesh Pallipadi
2010-10-23 2:13 ` tmhikaru
2010-10-25 10:12 ` Peter Zijlstra
2010-10-25 16:29 ` Venkatesh Pallipadi
2010-10-26 12:44 ` Peter Zijlstra
2010-10-26 14:05 ` Peter Zijlstra
2010-10-29 19:42 ` Peter Zijlstra
2010-11-09 18:55 ` Kyle McMartin
2010-11-09 19:02 ` Peter Zijlstra
2010-11-10 2:37 ` tmhikaru
2010-11-10 12:01 ` Peter Zijlstra
2010-11-10 3:45 ` Kyle McMartin
2010-11-10 12:00 ` Peter Zijlstra
2010-11-14 5:14 ` tmhikaru
2010-11-25 13:31 ` Damien Wyart
2010-11-25 14:03 ` Peter Zijlstra
2010-11-27 20:15 ` Peter Zijlstra
2010-11-28 4:26 ` Kyle McMartin
2010-11-28 11:40 ` Damien Wyart
2010-11-28 18:07 ` Valdis.Kletnieks
2010-11-29 11:38 ` Peter Zijlstra [this message]
2010-11-29 19:40 ` tmhikaru
2010-11-29 23:01 ` Peter Zijlstra
2010-11-30 14:59 ` Peter Zijlstra
2010-11-30 15:39 ` Kyle McMartin
2010-11-30 20:04 ` Kyle McMartin
2010-11-30 16:53 ` Damien Wyart
2010-11-30 17:29 ` Peter Zijlstra
2010-12-01 21:27 ` tmhikaru
2010-12-02 10:16 ` tmhikaru
2010-12-08 20:40 ` [tip:sched/urgent] sched: Cure more NO_HZ load average woes tip-bot for Peter Zijlstra
2010-11-30 20:01 ` High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later) tmhikaru
2010-11-30 16:49 ` Damien Wyart
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