RE: regression caused by bb6ab52f2bef ("intel_pstate: Do not set utilization update hook too early")
From: Jisheng Zhang
Date: Fri Jun 17 2016 - 11:54:15 EST
Dear Rafael,
I used intel_pstate.
I just tested v4.7-rc3, which should include commit 4578ee7e1def intel_pstate: Avoid
unnecessary synchronize_sched() during initialization, I can still get the same
wakeups, so it's not sufficient.
Another clue maybe helpful, I found these top2 wakeup/s is consistent, e.g
rcu_sched always gives about 10 wakeups/s, and tick_sched_timer gave
5.6-5.9 wakeups/s,
144.3 µs/s 10.0 Process [rcu_sched]
193.9 µs/s 5.7 Timer tick_sched_timer
Thanks,
Jisheng
________________________________________
From: Rafael J. Wysocki
Sent: Friday, June 17, 2016 23:42
To: Jisheng Zhang
Cc: Peter Zijlstra; Paul E. McKenney; Rafael J. Wysocki; Viresh Kumar; linux-pm@xxxxxxxxxxxxxxx; Linux Kernel Mailing List
Subject: Re: regression caused by bb6ab52f2bef ("intel_pstate: Do not set utilization update hook too early")
On Fri, Jun 17, 2016 at 5:40 PM, Rafael J. Wysocki wrote:
> On Fri, Jun 17, 2016 at 5:32 PM, Jisheng Zhang wrote:
>> Hi all,
>>
>> First of all, sorry for top post, only webmail is available now.
>>
>> Second, sorry again for report incorrect commit, I were too tired this morning so I remember the wrong commit. The regression is caused by bb6ab52f2bef ("intel_pstate: Do not set utilization update hook too early"), so I update the email title.
>
> OK, that makes much more sense. :-)
>
> And
>
> 4578ee7e1def intel_pstate: Avoid unnecessary synchronize_sched()
> during initialization
>
> is not sufficient I suppose?
I mean, it is not sufficient to reduce the number of wakeups again?