From: Daniel Lezcano <daniel.lezcano@free.fr> To: Colin Cross <ccross@android.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@lists.linux-foundation.org, Len Brown <len.brown@intel.com>, Kevin Hilman <khilman@ti.com>, Santosh Shilimkar <santosh.shilimkar@ti.com>, Amit Kucheria <amit.kucheria@linaro.org>, Arjan van de Ven <arjan@linux.intel.com>, Trinabh Gupta <g.trinabh@gmail.com>, Deepthi Dharwar <deepthi@linux.vnet.ibm.com>, linux-omap@vger.kernel.org, linux-tegra@vger.kernel.org Subject: Re: [PATCH 0/3] coupled cpuidle state support Date: Wed, 25 Jan 2012 15:04:18 +0100 [thread overview] Message-ID: <4F200BE2.2070301@free.fr> (raw) In-Reply-To: <CAMbhsRTbVqV6p0py9NGZrpFPf2yvp-B0dr+o-m7qbdja_-Lfzw@mail.gmail.com> On 01/20/2012 09:40 PM, Colin Cross wrote: > On Fri, Jan 20, 2012 at 12:46 AM, Daniel Lezcano > <daniel.lezcano@linaro.org> wrote: >> Hi Colin, >> >> this patchset could be interesting to resolve in a generic way the cpu >> dependencies. >> What is the status of this patchset ? > I can't do much with it right now, because I don't have any devices > that can do SMP idle with a v3.2 kernel. I've started working on an > updated version that avoids the spinlock, but it might be a while > before I can test and post it. I'm mostly looking for feedback on the > approach taken in this patch, and whether it will be useful for other > SoCs besides Tegra and OMAP4. Hi Colin, I will be happy to test your patchset. Do you have a pointer to a more recent kernel ? >> Did you have the opportunity to measure the power consumption with and >> without this patchset ? > Power consumption will be very dependent on the specific SoC in > question. The most important factors are the power savings of the > independent cpuidle state (normally WFI) vs. the hotplug state > (normally 1 cpu in OFF), and the workload being tested. > > On a very idle system, these patches result in the same total power as > hotplugging one cpu and letting the other idle normally. On a 25% > busy system, you might see a slight increase in power, as the best > independent cpuidle state might be WFI, vs 1 cpu in OFF mode in > hotplug. On OMAP4, that difference is small, on the order of 10 mW. > Once you hit the threshold where a hotplug governor would have > hotplugged in the second cpu (lets say 40%), the savings from these > patches are enormous, as you can hit the lowest power state up to 60% > of the time, where the hotplug solution would never be going below WFI > on both cpus. On OMAP4, that can be well over 100 mW. Interesting. Thanks -- Daniel
WARNING: multiple messages have this Message-ID (diff)
From: daniel.lezcano@free.fr (Daniel Lezcano) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 0/3] coupled cpuidle state support Date: Wed, 25 Jan 2012 15:04:18 +0100 [thread overview] Message-ID: <4F200BE2.2070301@free.fr> (raw) In-Reply-To: <CAMbhsRTbVqV6p0py9NGZrpFPf2yvp-B0dr+o-m7qbdja_-Lfzw@mail.gmail.com> On 01/20/2012 09:40 PM, Colin Cross wrote: > On Fri, Jan 20, 2012 at 12:46 AM, Daniel Lezcano > <daniel.lezcano@linaro.org> wrote: >> Hi Colin, >> >> this patchset could be interesting to resolve in a generic way the cpu >> dependencies. >> What is the status of this patchset ? > I can't do much with it right now, because I don't have any devices > that can do SMP idle with a v3.2 kernel. I've started working on an > updated version that avoids the spinlock, but it might be a while > before I can test and post it. I'm mostly looking for feedback on the > approach taken in this patch, and whether it will be useful for other > SoCs besides Tegra and OMAP4. Hi Colin, I will be happy to test your patchset. Do you have a pointer to a more recent kernel ? >> Did you have the opportunity to measure the power consumption with and >> without this patchset ? > Power consumption will be very dependent on the specific SoC in > question. The most important factors are the power savings of the > independent cpuidle state (normally WFI) vs. the hotplug state > (normally 1 cpu in OFF), and the workload being tested. > > On a very idle system, these patches result in the same total power as > hotplugging one cpu and letting the other idle normally. On a 25% > busy system, you might see a slight increase in power, as the best > independent cpuidle state might be WFI, vs 1 cpu in OFF mode in > hotplug. On OMAP4, that difference is small, on the order of 10 mW. > Once you hit the threshold where a hotplug governor would have > hotplugged in the second cpu (lets say 40%), the savings from these > patches are enormous, as you can hit the lowest power state up to 60% > of the time, where the hotplug solution would never be going below WFI > on both cpus. On OMAP4, that can be well over 100 mW. Interesting. Thanks -- Daniel
next prev parent reply other threads:[~2012-01-25 14:04 UTC|newest] Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-12-21 0:09 [PATCH 0/3] coupled cpuidle state support Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` [PATCH 1/3] cpuidle: refactor out cpuidle_enter_state Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` Colin Cross 2012-01-04 14:08 ` Jean Pihet 2012-01-04 14:08 ` [linux-pm] " Jean Pihet 2012-01-04 14:08 ` Jean Pihet [not found] ` <1324426147-16735-1-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org> 2011-12-21 0:09 ` [PATCH 2/3] cpuidle: fix error handling in __cpuidle_register_device Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` [PATCH 3/3] cpuidle: add support for states that affect multiple cpus Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 0:09 ` Colin Cross 2011-12-21 9:02 ` [PATCH 0/3] coupled cpuidle state support Arjan van de Ven 2011-12-21 9:02 ` Arjan van de Ven 2011-12-21 9:02 ` Arjan van de Ven [not found] ` <4EF1A0B4.5080307-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> 2011-12-21 9:40 ` Colin Cross 2011-12-21 9:40 ` Colin Cross 2011-12-21 9:40 ` Colin Cross 2011-12-21 9:44 ` Arjan van de Ven 2011-12-21 9:44 ` Arjan van de Ven 2011-12-21 9:44 ` Arjan van de Ven [not found] ` <4EF1AA8A.8060304-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> 2011-12-21 9:55 ` Colin Cross 2011-12-21 9:55 ` Colin Cross 2011-12-21 9:55 ` Colin Cross 2011-12-21 12:12 ` Arjan van de Ven 2011-12-21 12:12 ` Arjan van de Ven 2011-12-21 12:12 ` Arjan van de Ven 2011-12-21 19:05 ` Colin Cross 2011-12-21 19:05 ` Colin Cross 2011-12-21 19:05 ` Colin Cross [not found] ` <CAMbhsRRnKoR3YPWrZzVynVe+dcuU5v0siYvmp2vbBcS1hquC7Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2011-12-21 19:36 ` Arjan van de Ven 2011-12-21 19:36 ` Arjan van de Ven 2011-12-21 19:36 ` Arjan van de Ven 2011-12-21 19:42 ` Colin Cross 2011-12-21 19:42 ` [linux-pm] " Colin Cross 2011-12-21 19:42 ` Colin Cross [not found] ` <CAMbhsRSPCo9MSGp57Fv0sRdYUFcdwx8jEz1-CfX8LdKf8X4MVg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2011-12-22 8:35 ` Shilimkar, Santosh 2011-12-22 8:35 ` Shilimkar, Santosh 2011-12-22 8:35 ` Shilimkar, Santosh 2011-12-22 8:53 ` Arjan van de Ven 2011-12-22 8:53 ` [linux-pm] " Arjan van de Ven 2011-12-22 8:53 ` Arjan van de Ven 2011-12-22 9:30 ` Shilimkar, Santosh 2011-12-22 9:30 ` [linux-pm] " Shilimkar, Santosh 2011-12-22 9:30 ` Shilimkar, Santosh 2011-12-22 21:20 ` Colin Cross [not found] ` <4EF2F01E.8060307-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> 2011-12-22 21:20 ` [linux-pm] " Colin Cross 2011-12-22 21:20 ` Colin Cross 2011-12-22 21:20 ` Colin Cross 2011-12-22 8:35 ` Shilimkar, Santosh 2011-12-21 19:36 ` Arjan van de Ven [not found] ` <4EF1CD49.9020800-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> 2012-03-14 0:39 ` Colin Cross 2012-03-14 0:39 ` Colin Cross 2012-03-14 0:39 ` Colin Cross 2011-12-21 9:55 ` Colin Cross 2011-12-21 9:40 ` Colin Cross 2012-01-04 0:41 ` Kevin Hilman 2012-01-04 0:41 ` Kevin Hilman 2012-01-04 0:41 ` Kevin Hilman 2012-01-04 17:27 ` Shilimkar, Santosh 2012-01-04 17:27 ` Shilimkar, Santosh 2012-01-04 17:27 ` Shilimkar, Santosh 2012-01-20 8:46 ` Daniel Lezcano 2012-01-20 8:46 ` Daniel Lezcano 2012-01-20 8:46 ` Daniel Lezcano 2012-01-20 20:40 ` Colin Cross 2012-01-20 20:40 ` Colin Cross 2012-01-20 20:40 ` Colin Cross 2012-01-25 14:04 ` Daniel Lezcano [this message] 2012-01-25 14:04 ` Daniel Lezcano 2012-01-31 14:13 ` Daniel Lezcano 2012-01-31 14:13 ` Daniel Lezcano [not found] ` <CAMbhsRTbVqV6p0py9NGZrpFPf2yvp-B0dr+o-m7qbdja_-Lfzw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2012-01-27 8:54 ` [linux-pm] " Vincent Guittot 2012-01-27 8:54 ` Vincent Guittot 2012-01-27 8:54 ` Vincent Guittot 2012-01-27 17:32 ` Colin Cross 2012-01-27 17:32 ` Colin Cross 2012-01-27 17:32 ` Colin Cross [not found] ` <CAMbhsRQYVXTZ2pX4mBrM6=SyGTqn_GY8xsW4rt_e21zerEzctA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2012-02-01 12:13 ` Vincent Guittot 2012-02-01 12:13 ` Vincent Guittot 2012-02-01 12:13 ` Vincent Guittot 2012-02-01 14:59 ` Lorenzo Pieralisi 2012-02-01 14:59 ` [linux-pm] " Lorenzo Pieralisi 2012-02-01 14:59 ` Lorenzo Pieralisi 2012-02-01 17:30 ` Colin Cross 2012-02-01 17:30 ` Colin Cross 2012-02-01 17:30 ` Colin Cross 2012-02-01 18:07 ` Lorenzo Pieralisi 2012-02-01 18:07 ` [linux-pm] " Lorenzo Pieralisi 2012-02-01 18:07 ` Lorenzo Pieralisi 2012-02-03 1:19 ` Colin Cross 2012-02-03 1:19 ` [linux-pm] " Colin Cross 2012-02-03 1:19 ` Colin Cross 2012-03-13 23:52 ` Kevin Hilman 2012-03-13 23:52 ` Kevin Hilman [not found] ` <8762e8kqi6.fsf-l0cyMroinI0@public.gmane.org> 2012-03-14 0:28 ` Colin Cross 2012-03-14 0:28 ` Colin Cross 2012-03-14 0:28 ` Colin Cross 2012-03-14 0:47 ` Colin Cross 2012-03-14 0:47 ` Colin Cross 2012-03-14 0:47 ` Colin Cross [not found] ` <CAMbhsRRD2bdkcUZvScb-cF05e=R3h69bNVaTPFX4jBKBBOjuMg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2012-03-14 14:23 ` [linux-pm] " Kevin Hilman 2012-03-14 14:23 ` Kevin Hilman 2012-03-14 14:23 ` Kevin Hilman 2012-03-14 2:04 ` Arjan van de Ven 2012-03-14 2:04 ` Arjan van de Ven 2012-03-14 2:04 ` Arjan van de Ven 2012-03-14 2:21 ` Colin Cross 2012-03-14 2:21 ` Colin Cross 2012-03-14 2:21 ` Colin Cross 2011-12-21 0:09 Colin Cross
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