From: Arjan van de Ven <arjan@linux.intel.com>
To: Morten Rasmussen <morten.rasmussen@arm.com>,
Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Len Brown <len.brown@intel.com>,
Preeti Murthy <preeti.lkml@gmail.com>,
"mingo@redhat.com" <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
LKML <linux-kernel@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Lists linaro-kernel <linaro-kernel@lists.linaro.org>
Subject: Re: [RFC PATCH 3/3] idle: store the idle state index in the struct rq
Date: Mon, 03 Feb 2014 06:38:11 -0800 [thread overview]
Message-ID: <52EFA9D3.1030601@linux.intel.com> (raw)
In-Reply-To: <20140203125441.GD19029@e103034-lin>
On 2/3/2014 4:54 AM, Morten Rasmussen wrote:
>
> I'm therefore not convinced that idle state index is the right thing to
> give the scheduler. Using a cost metric would be better in my
> opinion.
I totally agree with this, and we may need two separate cost metrics
1) A latency driven one
2) A performance impact on
first one is pretty much the exit latency related time, sort of a "expected time to first instruction"
(currently menuidle has the 99.999% worst case number, which is not useful for this, but is a first
approximation). This is obviously the dominating number for expected-short running tasks
second on is more of a "is there any cache/TLB left or is it flushed" kind of metric. It's more tricky
to compute, since what is the cost of an empty cache (or even a cache migration) after all....
.... but I suspect it's in part what the scheduler will care about more for expected-long running tasks.
next prev parent reply other threads:[~2014-02-03 14:38 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-30 14:09 [RFC PATCH 0/3] cpuidle/sched: move main idle function in the idle.c Daniel Lezcano
2014-01-30 14:09 ` [RFC PATCH 1/3] cpuidle: split cpuidle_idle_call main function into functions Daniel Lezcano
2014-01-30 15:27 ` Peter Zijlstra
2014-01-30 15:39 ` Daniel Lezcano
2014-01-30 19:39 ` Nicolas Pitre
2014-01-31 14:10 ` Daniel Lezcano
2014-01-30 14:09 ` [RFC PATCH 2/3] cpuidle: move the cpuidle_idle_call function to idle.c Daniel Lezcano
2014-01-30 19:42 ` Nicolas Pitre
2014-01-30 14:09 ` [RFC PATCH 3/3] idle: store the idle state index in the struct rq Daniel Lezcano
2014-01-30 15:31 ` Peter Zijlstra
2014-01-30 16:27 ` Daniel Lezcano
2014-01-30 16:35 ` Peter Zijlstra
2014-01-30 17:25 ` Daniel Lezcano
2014-01-30 17:50 ` Lorenzo Pieralisi
2014-01-30 21:02 ` Nicolas Pitre
2014-01-31 9:46 ` Vincent Guittot
2014-01-31 10:04 ` Lorenzo Pieralisi
2014-01-31 10:44 ` Daniel Lezcano
2014-01-31 8:45 ` Preeti Murthy
2014-01-31 9:02 ` Peter Zijlstra
2014-01-31 9:39 ` Preeti U Murthy
2014-01-31 10:24 ` Peter Zijlstra
2014-01-31 14:04 ` Daniel Lezcano
2014-01-31 14:12 ` Dietmar Eggemann
2014-01-31 15:07 ` Arjan van de Ven
2014-01-31 15:37 ` Daniel Lezcano
2014-01-31 15:50 ` Arjan van de Ven
2014-01-31 16:35 ` Daniel Lezcano
2014-01-31 16:42 ` Arjan van de Ven
2014-01-31 18:19 ` Nicolas Pitre
2014-02-01 6:00 ` Brown, Len
2014-02-01 15:31 ` Nicolas Pitre
2014-02-01 19:39 ` Brown, Len
2014-02-01 20:13 ` Nicolas Pitre
2014-02-01 15:40 ` Lorenzo Pieralisi
2014-02-03 12:54 ` Morten Rasmussen
2014-02-03 14:38 ` Arjan van de Ven [this message]
2014-02-03 14:56 ` Peter Zijlstra
2014-02-03 16:17 ` Arjan van de Ven
2014-02-11 16:41 ` Peter Zijlstra
2014-02-11 17:12 ` Arjan van de Ven
2014-02-11 19:47 ` Peter Zijlstra
2014-02-12 15:16 ` Lorenzo Pieralisi
2014-02-12 16:14 ` Arjan van de Ven
2014-02-12 17:37 ` Lorenzo Pieralisi
2014-02-12 19:05 ` Nicolas Pitre
2014-02-04 9:14 ` Ingo Molnar
2014-02-04 14:53 ` Arjan van de Ven
2014-02-04 14:56 ` Arjan van de Ven
2014-02-03 14:58 ` Nicolas Pitre
2014-01-31 10:15 ` Daniel Lezcano
2014-02-03 6:33 ` Preeti U Murthy
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