From: Shawn Bohrer <shawn.bohrer@gmail.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: High scheduler wake up times
Date: Sun, 31 Jan 2010 14:50:43 -0600 [thread overview]
Message-ID: <20100131205043.GF27390@mediacenter.gateway.2wire.net> (raw)
In-Reply-To: <20100131102846.4d1e18aa@infradead.org>
On Sun, Jan 31, 2010 at 10:28:46AM -0800, Arjan van de Ven wrote:
> can you run powertop during your workload? maybe you're getting hit by
> some C state exit latencies tilting the rounding over the top just too
> many times...
Running 50 of the example processes and powertop on 2.6.32.7, with the
performance cpu governor:
Cn Avg residency P-states (frequencies)
C0 (cpu running) (24.7%)
polling 0.0ms ( 0.0%)
C1 mwait 0.3ms ( 0.0%)
C3 mwait 0.8ms (75.3%)
Wakeups-from-idle per second : 980.1 interval: 10.0s
no ACPI power usage estimate available
Top causes for wakeups:
76.2% (45066.9) worker_process : sys_epoll_wait (process_timeout)
22.0% (13039.2) <kernel core> : hrtimer_start_range_ns (tick_sched_timer)
1.5% (892.7) kipmi0 : schedule_timeout_interruptible (process_timeout)
0.2% (105.0) <kernel core> : add_timer (smi_timeout)
0.0% ( 10.5) <interrupt> : ata_piix
0.0% ( 10.1) <kernel core> : ipmi_timeout (ipmi_timeout)
I also tried booting with processor.max_cstate=0 which causes powertop
to no longer show any cstate information but I assumed that would keep
me fixed at C0. Booting with processor.max_cstate=0 didn't seem to make
any difference.
Thanks,
Shawn
next prev parent reply other threads:[~2010-01-31 20:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-30 23:45 High scheduler wake up times Shawn Bohrer
2010-01-30 23:56 ` Arjan van de Ven
2010-01-31 0:29 ` Shawn Bohrer
2010-01-31 0:02 ` Arjan van de Ven
2010-01-31 0:11 ` Arjan van de Ven
2010-01-31 0:35 ` Shawn Bohrer
2010-01-31 0:46 ` Shawn Bohrer
2010-01-31 0:47 ` Arjan van de Ven
2010-01-31 3:47 ` Shawn Bohrer
2010-01-31 18:28 ` Arjan van de Ven
2010-01-31 20:50 ` Shawn Bohrer [this message]
2010-02-01 8:51 ` Peter Zijlstra
2010-02-01 19:37 ` Shawn Bohrer
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