From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [PATCH V2 1/3] x86,idle: Quickly notice prediction failure for repeat mode Date: Mon, 17 Sep 2012 09:59:45 -0400 Message-ID: <50572CD1.700@redhat.com> References: <1347933209-25939-1-git-send-email-youquan.song@intel.com> <1347933209-25939-2-git-send-email-youquan.song@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1347933209-25939-2-git-send-email-youquan.song@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Youquan Song Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, arjan@linux.intel.com, lenb@kernel.org, Youquan Song List-Id: linux-acpi@vger.kernel.org On 09/17/2012 09:53 PM, Youquan Song wrote: > The prediction for future is difficult and when the cpuidle governor prediction > fails and govenor possibly choose the shallower C-state than it should. How to > quickly notice and find the failure becomes important for power saving. > > cpuidle menu governor has a method to predict the repeat pattern if there are 8 > C-states residency which are continuous and the same or very close, so it will > predict the next C-states residency will keep same residency time. Could I convince you to try out my variation on detect_repeating_intervals? :) http://people.redhat.com/riel/cstate/cstate-stddev-converge.patch I suspect that small change might help your code adapt to changed conditions even faster. -- All rights reversed