From: Viresh Kumar <viresh.kumar@linaro.org>
To: Stratos Karafotis <stratosk@semaphore.gr>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
cpufreq@vger.kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH linux-next] cpufreq: governors: Calculate iowait time only when necessary
Date: Thu, 28 Feb 2013 12:28:11 +0530 [thread overview]
Message-ID: <CAOh2x==vxM+qoebcUGNca50oeszwnqSfSzVPSEOyS6GKENudeg@mail.gmail.com> (raw)
In-Reply-To: <512E45E9.5020801@semaphore.gr>
On Wed, Feb 27, 2013 at 11:14 PM, Stratos Karafotis
<stratosk@semaphore.gr> wrote:
> Currently we always calculate the CPU iowait time and add it to idle time.
> If we are in ondemand and we use io_is_busy, we re-calculate iowait time
> and we subtract it from idle time.
>
> With this patch iowait time is calculated only when necessary avoiding
> the double call to get_cpu_iowait_time_us. We use a parameter in
> function get_cpu_idle_time to distinguish when the iowait time will be
> added to idle time or not, without the need of keeping the prev_io_wait.
>
> Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
> ---
> drivers/cpufreq/cpufreq_conservative.c | 2 +-
> drivers/cpufreq/cpufreq_governor.c | 46 +++++++++++++---------------------
> drivers/cpufreq/cpufreq_governor.h | 3 +--
> drivers/cpufreq/cpufreq_ondemand.c | 11 +++++++-
> 4 files changed, 29 insertions(+), 33 deletions(-)
I have really spent some 10-15 minutes reviewing this patch as initially it
looked to me like something is missing here and calculations are going wrong.
But it was fine :)
> diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
> index f3eb26c..46be2c4 100644
> --- a/drivers/cpufreq/cpufreq_ondemand.c
> +++ b/drivers/cpufreq/cpufreq_ondemand.c
> @@ -339,11 +339,20 @@ static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b,
> {
> + /* we need to re-evaluate prev_cpu_idle */
> + for_each_online_cpu(j) {
> + struct od_cpu_dbs_info_s *dbs_info;
> + dbs_info = &per_cpu(od_cpu_dbs_info, j);
Probably squash above two lines and give a blank line after it.
> + dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
> + &dbs_info->cdbs.prev_cpu_wall, od_tuners.io_is_busy);
> + }
> return count;
> }
And after that add my:
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
next prev parent reply other threads:[~2013-02-28 6:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-27 17:44 [PATCH linux-next] cpufreq: governors: Calculate iowait time only when necessary Stratos Karafotis
2013-02-28 6:58 ` Viresh Kumar [this message]
2013-02-28 16:57 ` [PATCH v2 " Stratos Karafotis
2013-03-01 3:48 ` Viresh Kumar
2013-03-21 23:54 ` Rafael J. Wysocki
2013-03-22 7:12 ` Stratos Karafotis
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='CAOh2x==vxM+qoebcUGNca50oeszwnqSfSzVPSEOyS6GKENudeg@mail.gmail.com' \
--to=viresh.kumar@linaro.org \
--cc=cpufreq@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=rjw@sisk.pl \
--cc=stratosk@semaphore.gr \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).