From: Nathan Zimmer <nzimmer@sgi.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: viresh.kumar@linaro.org, cpufreq@vger.kernel.org,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 0/2] cpufreq: cpufreq_driver_lock is hot on large systems
Date: Wed, 13 Mar 2013 15:50:41 -0500 [thread overview]
Message-ID: <5140E6A1.20107@sgi.com> (raw)
In-Reply-To: <3505617.pgqBjPDzlA@vostro.rjw.lan>
On 03/11/2013 06:23 PM, Rafael J. Wysocki wrote:
> On Friday, February 22, 2013 10:24:33 AM Nathan Zimmer wrote:
>> I am noticing the cpufreq_driver_lock is quite hot.
>> On an idle 512 system perf shows me most of the system time is spent on this
>> lock. This is quite significant as top shows 5% of time in system time.
>> My solution was to first convert the lock to a rwlock and then to the rcu.
>>
>> v2: Rebase
>>
>> v3: Read the RCU documentation instead of skimming it. Also I based on
>> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git pm+acpi-3.9-rc1
>> I assumed that was what you would prefer Rafael.
>>
>> v4: Removed an unnecessary syncronize_rcu().
>>
>>
>> Nathan Zimmer (2):
>> cpufreq: Convert the cpufreq_driver_lock to a rwlock
>> cpufreq: Convert the cpufreq_driver_lock to use the rcu
>>
>> drivers/cpufreq/cpufreq.c | 286 ++++++++++++++++++++++++++++++++++------------
>> 1 file changed, 211 insertions(+), 75 deletions(-)
> I'm going to take patch [1/2] for v3.10, but patch [2/2] still needs some
> work it seems. Is that correct? If so, are you going to send an update?
>
> Rafael
>
Viresh pointed out that cpufreq_cpu_data still needs a lock.
This means placing a vanilla spinlock back into __cpufreq_cpu_get which
is what I need to avoid. I haven't had the time I should to sort that out.
Nate
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Zimmer <nzimmer@sgi.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: <viresh.kumar@linaro.org>, <cpufreq@vger.kernel.org>,
<linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 0/2] cpufreq: cpufreq_driver_lock is hot on large systems
Date: Wed, 13 Mar 2013 15:50:41 -0500 [thread overview]
Message-ID: <5140E6A1.20107@sgi.com> (raw)
In-Reply-To: <3505617.pgqBjPDzlA@vostro.rjw.lan>
On 03/11/2013 06:23 PM, Rafael J. Wysocki wrote:
> On Friday, February 22, 2013 10:24:33 AM Nathan Zimmer wrote:
>> I am noticing the cpufreq_driver_lock is quite hot.
>> On an idle 512 system perf shows me most of the system time is spent on this
>> lock. This is quite significant as top shows 5% of time in system time.
>> My solution was to first convert the lock to a rwlock and then to the rcu.
>>
>> v2: Rebase
>>
>> v3: Read the RCU documentation instead of skimming it. Also I based on
>> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git pm+acpi-3.9-rc1
>> I assumed that was what you would prefer Rafael.
>>
>> v4: Removed an unnecessary syncronize_rcu().
>>
>>
>> Nathan Zimmer (2):
>> cpufreq: Convert the cpufreq_driver_lock to a rwlock
>> cpufreq: Convert the cpufreq_driver_lock to use the rcu
>>
>> drivers/cpufreq/cpufreq.c | 286 ++++++++++++++++++++++++++++++++++------------
>> 1 file changed, 211 insertions(+), 75 deletions(-)
> I'm going to take patch [1/2] for v3.10, but patch [2/2] still needs some
> work it seems. Is that correct? If so, are you going to send an update?
>
> Rafael
>
Viresh pointed out that cpufreq_cpu_data still needs a lock.
This means placing a vanilla spinlock back into __cpufreq_cpu_get which
is what I need to avoid. I haven't had the time I should to sort that out.
Nate
next prev parent reply other threads:[~2013-03-13 20:50 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-04 22:45 [PATCH 0/2] cpufreq: cpufreq_driver_lock is hot on large systems Nathan Zimmer
2013-02-04 22:45 ` [PATCH 1/2] cpufreq: Convert the cpufreq_driver_lock to a rwlock Nathan Zimmer
2013-02-05 8:11 ` Viresh Kumar
2013-02-04 22:45 ` [PATCH 2/2] cpufreq: Convert the cpufreq_driver_lock to use the rcu Nathan Zimmer
2013-02-05 1:07 ` [PATCH 0/2] cpufreq: cpufreq_driver_lock is hot on large systems Rafael J. Wysocki
2013-02-05 8:28 ` Viresh Kumar
2013-02-05 10:03 ` Rafael J. Wysocki
2013-02-05 9:58 ` Viresh Kumar
2013-02-05 10:13 ` Rafael J. Wysocki
2013-02-05 14:58 ` Nathan Zimmer
2013-02-05 22:00 ` Rafael J. Wysocki
2013-02-06 2:04 ` [PATCH v2 linux-next " Nathan Zimmer
2013-02-06 2:04 ` [PATCH v2 linux-next 1/2] cpufreq: Convert the cpufreq_driver_lock to a rwlock Nathan Zimmer
2013-02-06 2:47 ` Viresh Kumar
2013-02-06 2:04 ` [PATCH v2 linux-next 2/2] cpufreq: Convert the cpufreq_driver_lock to use the rcu Nathan Zimmer
2013-02-06 2:52 ` Viresh Kumar
2013-02-06 8:51 ` Viresh Kumar
2013-02-06 13:00 ` Rafael J. Wysocki
2013-02-07 23:29 ` Rafael J. Wysocki
2013-02-11 17:13 ` Nathan Zimmer
2013-02-11 19:36 ` Rafael J. Wysocki
2013-02-12 4:03 ` Nathan Zimmer
2013-02-12 15:59 ` Paul E. McKenney
2013-02-13 13:20 ` Rafael J. Wysocki
2013-02-20 23:56 ` [PATCH v3 0/2] cpufreq: cpufreq_driver_lock is hot on large systems Nathan Zimmer
2013-02-20 23:56 ` [PATCH v3 1/2] cpufreq: Convert the cpufreq_driver_lock to a rwlock Nathan Zimmer
2013-02-20 23:56 ` [PATCH v3 2/2] cpufreq: Convert the cpufreq_driver_lock to use the rcu Nathan Zimmer
2013-02-21 5:50 ` Viresh Kumar
2013-02-21 17:49 ` Nathan Zimmer
2013-02-21 17:49 ` Nathan Zimmer
2013-02-22 16:24 ` [PATCH v4 0/2] cpufreq: cpufreq_driver_lock is hot on large systems Nathan Zimmer
2013-02-22 16:24 ` [PATCH v4 1/2] cpufreq: Convert the cpufreq_driver_lock to a rwlock Nathan Zimmer
2013-02-23 3:57 ` Viresh Kumar
2013-02-22 16:24 ` [PATCH v4 2/2] cpufreq: Convert the cpufreq_driver_lock to use the rcu Nathan Zimmer
2013-02-23 3:39 ` Viresh Kumar
2013-02-25 20:07 ` Nathan Zimmer
2013-02-25 20:07 ` Nathan Zimmer
2013-03-11 23:23 ` [PATCH v4 0/2] cpufreq: cpufreq_driver_lock is hot on large systems Rafael J. Wysocki
2013-03-13 20:50 ` Nathan Zimmer [this message]
2013-03-13 20:50 ` Nathan Zimmer
2013-04-01 15:33 ` [PATCH v5] cpufreq: split the cpufreq_driver_lock and use the rcu (was cpufreq: cpufreq_driver_lock is hot on large systems) Nathan Zimmer
2013-04-01 16:28 ` Viresh Kumar
2013-04-01 17:17 ` Nathan Zimmer
2013-04-01 17:17 ` Nathan Zimmer
2013-04-01 20:11 ` [PATCH v6 0/2] cpufreq: cpufreq_driver_lock is hot on large systems Nathan Zimmer
2013-04-01 20:11 ` [PATCH v6 1/2] cpufreq: split the cpufreq_driver_lock and use the rcu Nathan Zimmer
2013-04-02 5:05 ` Viresh Kumar
2013-04-02 14:55 ` Nathan Zimmer
2013-04-02 14:59 ` Viresh Kumar
2013-04-02 15:40 ` Nathan Zimmer
2013-04-02 15:52 ` Viresh Kumar
2013-04-02 22:57 ` Rafael J. Wysocki
2013-04-03 5:25 ` Viresh Kumar
2013-04-01 20:11 ` [PATCH v6 2/2] cpufreq: covert the cpufreq_data_lock to a spinlock Nathan Zimmer
2013-04-01 20:41 ` Rafael J. Wysocki
2013-04-02 0:56 ` Nathan Zimmer
2013-04-02 5:04 ` Viresh Kumar
2013-04-02 12:48 ` Rafael J. Wysocki
2013-04-02 14:58 ` Nathan Zimmer
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=5140E6A1.20107@sgi.com \
--to=nzimmer@sgi.com \
--cc=cpufreq@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=rjw@sisk.pl \
--cc=viresh.kumar@linaro.org \
/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.