Messages in this thread | | | From | "Chalhoub, Nicole" <> | Subject | RE: [PATCH] CPUIdle: Reevaluate C-states under CPU load to favor deeper C-states | Date | Wed, 9 Nov 2011 18:06:41 +0000 |
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Hi Deepthi,
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-----Original Message----- > From: Deepthi Dharwar [mailto:deepthi@linux.vnet.ibm.com] > Sent: Wednesday, November 09, 2011 12:13 PM > To: Hilman, Kevin > Cc: linux-kernel@vger.kernel.org; Arjan van de Ven; linux-arm- > kernel@lists.infradead.org; linux-omap@vger.kernel.org; linux- > pm@lists.linux-foundation.org; Chalhoub, Nicole > Subject: Re: [PATCH] CPUIdle: Reevaluate C-states under CPU load to favor > deeper C-states
[...] > By setting timers when we enter non-deepest C-state possible, such that > when it fires we > can re-evaluate and try moving into deeper and deeper C-states enhancing > the > power savings is a good feature to have. > > Looking at the current implementation, is it possible to have it as > configurable option > where one can enable/disable this functionality through the backhand > driver ?
The timeout values of the c state timers are set in the backhand driver. By setting the timeout to 0 the timers will not fire so you'll not have this functionality enabled
> Also I am thinking, instead of having them in governor > wouldnt it be a good idea to have it implemented in > the backhand driver itself ? > --Deepthi
In fact each C-state had its own configurable timer, so it is a parameter characterizing a C-state as it is for the exit_latency and target_residency parameters. And we wanted the timer to fire only when we do not go in deep Cstate due to a high load. This decision is made in the CPU idle governor. So the functionality should be seen from the governor..
Thanks and Regards Nicole
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