From: Peter Zijlstra <peterz@infradead.org>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: tglx@linutronix.de, arjan@linux.intel.com,
linux-kernel@vger.kernel.org, jacob.jun.pan@intel.com,
fweisbec@gmail.com, frederic@kernel.org,
daniel.lezcano@linaro.org, amit.kucheria@linaro.org,
edubezval@gmail.com, viresh.kumar@linaro.org,
rui.zhang@intel.com
Subject: Re: [PATCH V2] idle/intel_powerclamp: Redesign idle injection to use bandwidth control mechanism
Date: Fri, 13 Feb 2015 14:31:58 +0100 [thread overview]
Message-ID: <20150213133158.GP2896@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20150209044852.6231.66456.stgit@preeti.in.ibm.com>
On Mon, Feb 09, 2015 at 10:19:43AM +0530, Preeti U Murthy wrote:
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 8db31ef..6a7ccb2 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -3002,6 +3002,12 @@ extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
>
> #ifdef CONFIG_CGROUP_SCHED
> extern struct task_group root_task_group;
> +extern int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us);
> +extern int tg_set_cfs_period(struct task_group *tg, long cfs_period_us);
> +#else
> +
> +static inline int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us);
> +static inline int tg_set_cfs_period(struct task_group *tg, long cfs_period_us);
> #endif /* CONFIG_CGROUP_SCHED */
Instead you might want to make the whole powerclamp thing depend on
CONFIG_CFS_BANDWIDTH.
Also, exposing these and root_task_group is of course vile. Not to
mention you change the user (cgroup) interface without mention.
In any case, I cannot see how this could ever work. Bandwidth is shared
across CPUs; nothing will even attempt to get CPUs to idle at the same
time.
next prev parent reply other threads:[~2015-02-13 13:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-09 4:49 [PATCH V2] idle/intel_powerclamp: Redesign idle injection to use bandwidth control mechanism Preeti U Murthy
2015-02-09 7:32 ` Steven Noonan
2015-02-09 11:51 ` Preeti U Murthy
2015-02-09 17:56 ` Steven Noonan
2015-02-09 18:14 ` Steven Noonan
2015-02-11 9:00 ` Preeti U Murthy
2015-02-13 13:31 ` Peter Zijlstra [this message]
2015-02-13 14:03 ` Arjan van de Ven
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