From: Peter Zijlstra <peterz@infradead.org>
To: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
mturquette@linaro.org, amit.kucheria@linaro.org,
vincent.guittot@linaro.org, daniel.lezcano@linaro.org,
Morten.Rasmussen@arm.com, efault@gmx.de,
nicolas.pitre@linaro.org, dietmar.eggemann@arm.com,
pjt@google.com, bsegall@google.com, mingo@kernel.org,
linaro-kernel@lists.linaro.org,
Preeti U Murthy <preeti@linux.vnet.ibm.com>
Subject: Re: [RFC 1/2] sched/fair: Add cumulative average of load_avg_contrib to a task
Date: Tue, 11 Nov 2014 18:30:23 +0100 [thread overview]
Message-ID: <20141111173023.GP10501@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <546222C7.2030000@linux.vnet.ibm.com>
On Tue, Nov 11, 2014 at 08:22:55PM +0530, Shilpasri G Bhat wrote:
> On 11/10/2014 07:19 PM, Peter Zijlstra wrote:
> > It it broken because who says rq->prev still exists?
>
> 'task_cumulative_load()' is handled by the cpufreq governor's kworker.
> And the kworker is queued only if there is task running on cpu which
> guarantees the existence of rq->prev in a running state.
Not so, there is no guarantee it will still be running by the time the
kworker actually comes around to running.
next prev parent reply other threads:[~2014-11-11 17:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-10 5:45 [RFC 0/2] CPU frequency scaled from a task's load on an idle wakeup Shilpasri G Bhat
2014-11-10 5:45 ` [RFC 1/2] sched/fair: Add cumulative average of load_avg_contrib to a task Shilpasri G Bhat
2014-11-10 13:49 ` Peter Zijlstra
2014-11-11 14:52 ` Shilpasri G Bhat
2014-11-11 17:29 ` Peter Zijlstra
2014-11-11 17:30 ` Peter Zijlstra [this message]
2014-11-10 5:45 ` [RFC 2/2] cpufreq: governor: CPU frequency scaled from task's cumulative-load on an idle wakeup Shilpasri G Bhat
2014-11-10 9:19 ` [RFC 0/2] CPU frequency scaled from a task's load " Shilpasri G Bhat
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