From: Alex Shi <alex.shi@intel.com>
To: Phil Carmody <pc+lkml@asdf.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [patch v7 05/21] sched: log the cpu utilization at rq
Date: Mon, 06 May 2013 20:35:35 +0800 [thread overview]
Message-ID: <5187A397.9040102@intel.com> (raw)
In-Reply-To: <20130506120318.GM21274@fatphil.org>
On 05/06/2013 08:03 PM, Phil Carmody wrote:
>> > + period = rq->avg.runnable_avg_period ? rq->avg.runnable_avg_period : 1;
>> > + rq->util = (u64)(rq->avg.runnable_avg_sum << SCHED_POWER_SHIFT)
>> > + / period;
> Greetings, Alex.
>
> That cast achieves nothing where it is. If the shift has overflowed,
> then you've already lost information; and if it can't overflow, then
> it's not needed at all.
>
> It's itsy-bitsy, but note that there exists a div_u64(u64 dividend,
> u32 divisor) helper which may be implemented to be superior to just '/'.
> (And also note that the assignment to ``period'' is a good candidate for
> gcc's ``?:'' operator.)
>
> If you pull the cast inside the brackets, then you may add my
> Reviewed-by: Phil Carmody <pc+lkml@asdf.org>
You are right, Phil!
Thanks for review! :)
--
Thanks
Alex
next prev parent reply other threads:[~2013-05-06 12:35 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-04 2:00 [patch v7 0/21] sched: power aware scheduling Alex Shi
2013-04-04 2:00 ` [patch v7 01/21] Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking" Alex Shi
2013-04-04 2:00 ` [patch v7 02/21] sched: set initial value of runnable avg for new forked task Alex Shi
2013-05-06 3:24 ` Preeti U Murthy
2013-04-04 2:00 ` [patch v7 03/21] sched: add sched balance policies in kernel Alex Shi
2013-04-04 2:00 ` [patch v7 04/21] sched: add sysfs interface for sched_balance_policy selection Alex Shi
2013-04-04 2:00 ` [patch v7 05/21] sched: log the cpu utilization at rq Alex Shi
2013-05-06 3:26 ` Preeti U Murthy
2013-05-06 5:22 ` Alex Shi
2013-05-06 12:03 ` Phil Carmody
2013-05-06 12:35 ` Alex Shi [this message]
2013-05-06 21:19 ` Paul Turner
2013-04-04 2:00 ` [patch v7 06/21] sched: add new sg/sd_lb_stats fields for incoming fork/exec/wake balancing Alex Shi
2013-04-04 2:00 ` [patch v7 07/21] sched: move sg/sd_lb_stats struct ahead Alex Shi
2013-04-04 2:00 ` [patch v7 08/21] sched: scale_rt_power rename and meaning change Alex Shi
2013-04-04 2:00 ` [patch v7 09/21] sched: get rq potential maximum utilization Alex Shi
2013-04-04 2:00 ` [patch v7 10/21] sched: add power aware scheduling in fork/exec/wake Alex Shi
2013-04-04 2:00 ` [patch v7 11/21] sched: add sched_burst_threshold_ns as wakeup burst indicator Alex Shi
2013-04-04 2:00 ` [patch v7 12/21] sched: using avg_idle to detect bursty wakeup Alex Shi
2013-04-04 2:00 ` [patch v7 13/21] sched: packing transitory tasks in wakeup power balancing Alex Shi
2013-04-04 2:00 ` [patch v7 14/21] sched: add power/performance balance allow flag Alex Shi
2013-04-04 2:00 ` [patch v7 15/21] sched: pull all tasks from source group Alex Shi
2013-04-04 5:59 ` Namhyung Kim
2013-04-06 11:49 ` Alex Shi
2013-04-04 2:00 ` [patch v7 16/21] sched: no balance for prefer_sibling in power scheduling Alex Shi
2013-05-06 3:26 ` Preeti U Murthy
2013-04-04 2:00 ` [patch v7 17/21] sched: add new members of sd_lb_stats Alex Shi
2013-04-04 2:00 ` [patch v7 18/21] sched: power aware load balance Alex Shi
2013-04-04 2:01 ` [patch v7 19/21] sched: lazy power balance Alex Shi
2013-04-04 2:01 ` [patch v7 20/21] sched: don't do power balance on share cpu power domain Alex Shi
2013-04-08 3:17 ` Preeti U Murthy
2013-04-08 3:25 ` Preeti U Murthy
2013-04-08 4:19 ` Alex Shi
2013-04-04 2:01 ` [patch v7 21/21] sched: make sure select_tas_rq_fair get a cpu Alex Shi
2013-04-11 21:02 ` [patch v7 0/21] sched: power aware scheduling Len Brown
2013-04-12 8:46 ` Alex Shi
2013-04-12 16:23 ` Borislav Petkov
2013-04-12 16:48 ` Mike Galbraith
2013-04-12 17:12 ` Borislav Petkov
2013-04-14 1:36 ` Alex Shi
2013-04-17 21:53 ` Len Brown
2013-04-18 1:51 ` Mike Galbraith
2013-04-26 15:11 ` Mike Galbraith
2013-04-30 5:16 ` Mike Galbraith
2013-04-30 8:30 ` Mike Galbraith
2013-04-30 8:41 ` Ingo Molnar
2013-04-30 9:35 ` Mike Galbraith
2013-04-30 9:49 ` Mike Galbraith
2013-04-30 9:56 ` Mike Galbraith
2013-05-17 8:06 ` Preeti U Murthy
2013-05-20 1:01 ` Alex Shi
2013-05-20 2:30 ` Preeti U Murthy
2013-04-14 1:28 ` Alex Shi
2013-04-14 5:10 ` Alex Shi
2013-04-14 15:59 ` Borislav Petkov
2013-04-15 6:04 ` Alex Shi
2013-04-15 6:16 ` Alex Shi
2013-04-15 9:52 ` Borislav Petkov
2013-04-15 13:50 ` Alex Shi
2013-04-15 23:12 ` Borislav Petkov
2013-04-16 0:22 ` Alex Shi
2013-04-16 10:24 ` Borislav Petkov
2013-04-17 1:18 ` Alex Shi
2013-04-17 7:38 ` Borislav Petkov
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