From: Catalin Marinas <catalin.marinas@arm.com>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>,
David Lang <david@lang.hm>,
"len.brown@intel.com" <len.brown@intel.com>,
"alex.shi@intel.com" <alex.shi@intel.com>,
"corbet@lwn.net" <corbet@lwn.net>,
"peterz@infradead.org" <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"efault@gmx.de" <efault@gmx.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
"preeti@linux.vnet.ibm.com" <preeti@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
"pjt@google.com" <pjt@google.com>, Ingo Molnar <mingo@kernel.org>
Subject: Re: power-efficient scheduling design
Date: Fri, 21 Jun 2013 22:23:25 +0100 [thread overview]
Message-ID: <CAHkRjk5G7XJxzjcWa4BqRxz0AtAAh_-Eomzk4+dQRaFk1=HQqA@mail.gmail.com> (raw)
In-Reply-To: <51C47377.2000208@linux.intel.com>
On 21 June 2013 16:38, Arjan van de Ven <arjan@linux.intel.com> wrote:
> On 6/21/2013 1:50 AM, Morten Rasmussen wrote:
>> A hint when a task is moved to a new cpu is too late if the migration
>> shouldn't have happened at all. If the scheduler knows that the cpu is
>> able to switch to a higher p-state it can decide to wait for the p-state
>> change instead of migrating the task and waking up another cpu.
>
> oops sorry I misread your mail (lack of early coffee I suppose)
>
> I can see your point of having a thing for "did we ask for all the performance
> we could ask for" prior to doing a load balance (although, for power efficiency,
> if you have two tasks that could run in parallel, it's usually better to
> run them in parallel... so likely we should balance anyway)
Not necessarily, especially if parallel running implies powering up a
full cluster just for one CPU (it depends on the hardware but for
example a cluster may not be able to go in deeper sleep states unless
all the CPUs in that cluster are idle).
--
Catalin
next prev parent reply other threads:[~2013-06-21 21:23 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-30 13:47 [RFC] Comparison of power-efficient scheduling patch sets Morten Rasmussen
2013-05-31 1:17 ` Alex Shi
2013-05-31 8:23 ` Alex Shi
2013-05-31 10:52 ` power-efficient scheduling design Ingo Molnar
2013-06-03 14:59 ` Arjan van de Ven
2013-06-03 15:43 ` Ingo Molnar
2013-06-04 15:03 ` Morten Rasmussen
2013-06-07 6:26 ` Preeti U Murthy
2013-06-20 15:23 ` Ingo Molnar
2013-06-05 9:56 ` Amit Kucheria
2013-06-07 6:03 ` Preeti U Murthy
2013-06-07 14:51 ` Catalin Marinas
2013-06-07 18:08 ` Preeti U Murthy
2013-06-07 17:36 ` David Lang
2013-06-09 4:33 ` Preeti U Murthy
2013-06-08 11:28 ` Catalin Marinas
2013-06-08 14:02 ` Rafael J. Wysocki
2013-06-09 3:42 ` Preeti U Murthy
2013-06-09 22:53 ` Catalin Marinas
2013-06-10 16:25 ` Daniel Lezcano
2013-06-12 0:27 ` David Lang
2013-06-12 1:48 ` Arjan van de Ven
2013-06-12 9:48 ` Amit Kucheria
2013-06-12 16:22 ` David Lang
2013-06-12 10:20 ` Catalin Marinas
2013-06-12 15:24 ` Arjan van de Ven
2013-06-12 17:04 ` Catalin Marinas
2013-06-12 9:50 ` Daniel Lezcano
2013-06-12 16:30 ` David Lang
2013-06-11 0:50 ` Rafael J. Wysocki
2013-06-13 4:32 ` Preeti U Murthy
2013-06-09 4:23 ` Preeti U Murthy
2013-06-07 15:23 ` Arjan van de Ven
2013-06-14 16:05 ` Morten Rasmussen
2013-06-17 11:23 ` Catalin Marinas
2013-06-18 1:37 ` David Lang
2013-06-18 10:23 ` Morten Rasmussen
2013-06-18 17:39 ` David Lang
2013-06-19 12:39 ` Morten Rasmussen
2013-06-18 15:20 ` Arjan van de Ven
2013-06-18 17:47 ` David Lang
2013-06-18 19:36 ` Arjan van de Ven
2013-06-19 15:39 ` Arjan van de Ven
2013-06-19 17:00 ` Morten Rasmussen
2013-06-19 17:08 ` Arjan van de Ven
2013-06-21 8:50 ` Morten Rasmussen
2013-06-21 15:29 ` Arjan van de Ven
2013-06-21 15:38 ` Arjan van de Ven
2013-06-21 21:23 ` Catalin Marinas [this message]
2013-06-21 21:34 ` Arjan van de Ven
2013-06-23 23:32 ` Benjamin Herrenschmidt
2013-06-24 10:07 ` Catalin Marinas
2013-06-24 15:26 ` Arjan van de Ven
2013-06-24 21:59 ` Benjamin Herrenschmidt
2013-06-24 23:10 ` Arjan van de Ven
2013-06-18 19:06 ` Catalin Marinas
2013-06-21 15:06 ` Morten Rasmussen
2013-06-23 10:55 ` Ingo Molnar
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