From: Arjan van de Ven <arjan@infradead.org>
To: "Éric Piel" <eric.piel@tremplin-utc.net>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
mingo@elte.hu, peterz@infradead.org, tglx@linutronix.de,
davej@redhat.com, cpufreq@vger.kernel.org
Subject: Re: [PATCH 7/7] ondemand: Solve the big performance issue with ondemand during disk IO
Date: Mon, 19 Apr 2010 06:43:25 -0700 [thread overview]
Message-ID: <20100419064325.49cb3108@infradead.org> (raw)
In-Reply-To: <4BCC147B.10708@tremplin-utc.net>
On Mon, 19 Apr 2010 10:29:47 +0200
Éric Piel <eric.piel@tremplin-utc.net> wrote:
> >
> > The problem and fix are both verified with the "perf timechar" tool.
> Hi,
> I don't doubt that keeping the cpu full frequency during IO can
> improve some specific workloads, however in your log message you
> don't explain how much we are loosing.
first of all, it's so bad that people will just turn the whole power
management off... at which point fixing the really bad bug is actually
quite a win
>
> How much more energy is consumed when doing a "updatedb" or "find /" ?
on the machines I used this on (Core i7's) it's actually hardly
measurable. All CPUs I have access to turn the voltage entirely off
during idle, so while the frequency is higher, if you're mostly IO
bound, it's only for very short durations... while still being mostly
"off".
--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
next prev parent reply other threads:[~2010-04-19 13:41 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-18 18:59 [PATCH 0/7] Fix performance issue with ondemand governor Arjan van de Ven
2010-04-18 19:00 ` [PATCH 1/7] sched: add a comment to get_cpu_idle_time_us() Arjan van de Ven
2010-04-26 19:25 ` Rik van Riel
2010-04-18 19:01 ` [PATCH 2/7] sched: introduce a function to update the idle statistics Arjan van de Ven
2010-04-26 20:11 ` Rik van Riel
2010-04-18 19:01 ` [PATCH 3/7] sched: update the idle statistics in get_cpu_idle_time_us() Arjan van de Ven
2010-04-26 20:36 ` Rik van Riel
2010-04-18 19:02 ` [PATCH 4/7] sched: fold updating of the last update time into update_ts_time_stats() Arjan van de Ven
2010-04-26 20:58 ` Rik van Riel
2010-04-18 19:02 ` [PATCH 5/7] sched: eliminate the ts->idle_lastupdate field Arjan van de Ven
2010-04-26 21:00 ` Rik van Riel
2010-04-18 19:03 ` [PATCH 6/7] sched: introduce get_cpu_iowait_time_us() Arjan van de Ven
2010-04-26 21:05 ` Rik van Riel
2010-04-18 19:03 ` [PATCH 7/7] ondemand: Solve the big performance issue with ondemand during disk IO Arjan van de Ven
2010-04-19 8:29 ` Éric Piel
2010-04-19 13:43 ` Arjan van de Ven [this message]
2010-04-19 14:30 ` Éric Piel
2010-04-19 14:47 ` Arjan van de Ven
2010-04-20 9:24 ` Thomas Renninger
2010-04-27 0:29 ` Mike Chan
2010-04-27 13:01 ` Pavel Machek
2010-04-27 18:10 ` Mike Chan
2010-04-19 9:09 ` Tvrtko Ursulin
2010-04-19 13:46 ` Arjan van de Ven
2010-04-19 15:29 ` Tvrtko Ursulin
2010-04-20 0:47 ` Arjan van de Ven
2010-04-20 9:10 ` Tvrtko Ursulin
2010-04-20 11:02 ` Arjan van de Ven
2010-04-28 8:57 ` Tvrtko Ursulin
2010-04-23 5:26 ` Pavel Machek
2010-04-20 9:29 ` Thomas Renninger
2010-04-20 11:07 ` Arjan van de Ven
2010-04-23 5:24 ` Pavel Machek
2010-04-23 5:38 ` Willy Tarreau
2010-04-23 8:50 ` Thomas Renninger
2010-04-23 16:08 ` Arjan van de Ven
2010-04-27 11:39 ` Thomas Renninger
2010-05-04 3:48 ` [PATCH 8/7] cpufreq: make the iowait-is-busy-time a sysfs tunable Arjan van de Ven
2010-05-04 4:16 ` Willy Tarreau
2010-05-04 5:43 ` Pavel Machek
2010-05-04 13:51 ` Rik van Riel
2010-04-23 14:10 ` [PATCH 7/7] ondemand: Solve the big performance issue with ondemand during disk IO Arjan van de Ven
2010-04-23 15:35 ` Willy Tarreau
2010-04-23 13:52 ` Arjan van de Ven
2010-04-23 8:38 ` Pavel Machek
2010-04-23 16:06 ` Arjan van de Ven
2010-04-24 4:56 ` Pavel Machek
2010-05-01 23:29 ` Arjan van de Ven
2010-04-26 21:30 ` Rik van Riel
2010-04-26 21:41 ` [PATCH 0/7] Fix performance issue with ondemand governor Dave Jones
2010-04-26 21:45 ` Dominik Brodowski
2010-04-26 21:59 ` Rik van Riel
2010-04-26 22:05 ` Dominik Brodowski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100419064325.49cb3108@infradead.org \
--to=arjan@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=cpufreq@vger.kernel.org \
--cc=davej@redhat.com \
--cc=eric.piel@tremplin-utc.net \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.