On Tue, Feb 5, 2013 at 6:37 AM, Rafael J. Wysocki rjw@sisk.pl wrote:
On Monday, February 04, 2013 04:45:11 PM 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 signifigant 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.
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 | 139 ++++++++++++++++++++++++++-------------------- 1 file changed, 79 insertions(+), 60 deletions(-)
I like these changes.
Viresh, anyone, any comments?
Hi Nathan/Rafael,
Even i liked the basic idea behind the patchset, but didn't like the way it is divided into patches. For me, it is highly discouraged to undo something that you added in the same patchset. And you did exactly the same thing.
Patch 2 is revert of 1 + rcu stuff.
So, i would expect a single patch, i.e. merge of both patches + rebased on latest stuff.
-- viresh
On Tuesday, February 05, 2013 01:58:20 PM Viresh Kumar wrote:
On Tue, Feb 5, 2013 at 6:37 AM, Rafael J. Wysocki rjw@sisk.pl wrote:
On Monday, February 04, 2013 04:45:11 PM 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 signifigant 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.
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 | 139 ++++++++++++++++++++++++++-------------------- 1 file changed, 79 insertions(+), 60 deletions(-)
I like these changes.
Viresh, anyone, any comments?
Hi Nathan/Rafael,
Even i liked the basic idea behind the patchset, but didn't like the way it is divided into patches. For me, it is highly discouraged to undo something that you added in the same patchset. And you did exactly the same thing.
Patch 2 is revert of 1 + rcu stuff.
So, i would expect a single patch, i.e. merge of both patches + rebased on latest stuff.
I actually don't agree with that, becuase the Nathan's apprach shows the reasoning that leads to the RCU introduction quite clearly. So if you don't have technical problems with the patchset, I'm going to take it as is.
Thanks, Rafael
On Tue, Feb 5, 2013 at 3:33 PM, Rafael J. Wysocki rjw@sisk.pl wrote:
I actually don't agree with that, becuase the Nathan's apprach shows the reasoning that leads to the RCU introduction quite clearly. So if you don't have technical problems with the patchset, I'm going to take it as is.
Great!!
Okay.. I don't have any technical problems with it, i reviewed most of it carefully. The only pending thing is rebase on linux-next, after that i can give my ack for it.
On Tuesday, February 05, 2013 03:28:30 PM Viresh Kumar wrote:
On Tue, Feb 5, 2013 at 3:33 PM, Rafael J. Wysocki rjw@sisk.pl wrote:
I actually don't agree with that, becuase the Nathan's apprach shows the reasoning that leads to the RCU introduction quite clearly. So if you don't have technical problems with the patchset, I'm going to take it as is.
Great!!
Okay.. I don't have any technical problems with it, i reviewed most of it carefully. The only pending thing is rebase on linux-next, after that i can give my ack for it.
Yes, it would be great if it were rebased and retested.
Thanks, Rafael
Ok, I'll rebase and retest from linux-next then.
________________________________________ From: Rafael J. Wysocki [rjw@sisk.pl] Sent: Tuesday, February 05, 2013 4:13 AM To: Viresh Kumar Cc: Nathan Zimmer; linux-kernel@vger.kernel.org; linux-pm@vger.kernel.org; cpufreq@vger.kernel.org; Shawn Guo; linaro-dev@lists.linaro.org Subject: Re: [PATCH 0/2] cpufreq: cpufreq_driver_lock is hot on large systems
On Tuesday, February 05, 2013 03:28:30 PM Viresh Kumar wrote:
On Tue, Feb 5, 2013 at 3:33 PM, Rafael J. Wysocki rjw@sisk.pl wrote:
I actually don't agree with that, becuase the Nathan's apprach shows the reasoning that leads to the RCU introduction quite clearly. So if you don't have technical problems with the patchset, I'm going to take it as is.
Great!!
Okay.. I don't have any technical problems with it, i reviewed most of it carefully. The only pending thing is rebase on linux-next, after that i can give my ack for it.
Yes, it would be great if it were rebased and retested.
Thanks, Rafael
-- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.
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Nathan Zimmer -
Rafael J. Wysocki -
Viresh Kumar