From: Arjan van de Ven <arjan@linux.intel.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
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: Mon, 24 Jun 2013 16:10:29 -0700 [thread overview]
Message-ID: <51C8D1E5.60804@linux.intel.com> (raw)
In-Reply-To: <1372111148.3944.161.camel@pasglop>
On 6/24/2013 2:59 PM, Benjamin Herrenschmidt wrote:
> On Mon, 2013-06-24 at 08:26 -0700, Arjan van de Ven wrote:
>>
>> to bring the system back up if all cores in the whole system are idle and power gated,
>> memory in SR etc... is typically < 250 usec (depends on the exact version
>> of the cpu etc). But the moment even one core is running, that core will keep the system
>> out of such deep state, and waking up a consecutive entity is much faster
>>
>> to bring just a core out of power gating is more in the 40 to 50 usec range
>
> Out of curiosity, what happens to PCIe when you bring a package down
> like this ?
PCIe devices can communicate latency requirements (LTR) if they need something
more aggressive than this; otherwise 250 usec afaik falls within what doesn't
break (devices need to cope with arbitrage/etc delays anyway)
and with PCIe link power management there are delays regardless; once a PCIe link gets powered
back on the memory controller/etc also will come back online
next prev parent reply other threads:[~2013-06-24 23:10 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
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 [this message]
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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