From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752812AbaCGL5W (ORCPT ); Fri, 7 Mar 2014 06:57:22 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:59172 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751578AbaCGL5T (ORCPT ); Fri, 7 Mar 2014 06:57:19 -0500 From: "Rafael J. Wysocki" To: Tuukka Tikkanen Cc: linux-pm@vger.kernel.org, daniel.lezcano@linaro.org, linux-kernel@vger.kernel.org, Len Brown Subject: Re: [PATCH 0/7] Cpuidle: Minor fixes Date: Fri, 07 Mar 2014 13:12:31 +0100 Message-ID: <2675767.poCYkWDpin@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.13.0+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <2037831.3FXZ8RTMPh@vostro.rjw.lan> References: <1393223377-5744-1-git-send-email-tuukka.tikkanen@linaro.org> <2037831.3FXZ8RTMPh@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, February 26, 2014 01:46:25 AM Rafael J. Wysocki wrote: > On Monday, February 24, 2014 08:29:30 AM Tuukka Tikkanen wrote: > > This set of patches makes some minor changes to menu governor and the poll > > idle state. > > > > Patch 1 is simply a rename of a variable to make the name better represent > > the contained information. > > > > Patch 2 fixes calculating actual residency in cases where the entered state > > is different from the state decided by the menu governor. > > > > Patch 3 makes sure the menu governor timer coefficients are not updated > > with values that might cause a coefficient to reach a value greater than > > unity. > > > > Patch 4 fixes calculation actual residency in cases where the entered state > > does not support measuring residency. In such cases the residency time > > is taken from time remaining until next timer expiry. The timer is expected > > to go off at the start of exit latency, not after it. Therefore the exit > > latency must not be substracted from the assumed value. > > > > Patch 5 moves the performance multiplier based comparison out of the state > > selection loop by changing it into a latency requirement. This allows > > using a generic state selection function accepting only (duration, latency) > > tuple as input. The change is possible by noting that performance multiplier > > is used only to check for a minimum predicted idle duration to exit latency > > ratio. As predicted idle duration is a constant for the loop, the maximum > > allowed latency can be calculated outside of the loop. > > > > Patch 6 prevents using negative values from tick_nohz_get_sleep_length() > > in the menu governor. If unchecked, the negative values are used as huge > > unsigned values. Negative values occur fairly often (e.g. on x86_64 I've > > seen this happen several times per minute) on a busy system, allowing > > the deepest state to win the selection while the shallowest should be picked. > > > > Patch 7 adds CPUIDLE_FLAG_TIME_VALID to poll_idle. I do not know of any > > platfrom where cpu_relax() would break ktime_get() and in fact poll_idle > > uses ktime_get itself. > > (Note: poll_idle updates dev->last_residency for some reason. Does it ever > > get called without going through cpuidle_enter_state, which will overwrite > > the value? Even if some state redirects to this state, the call will > > eventually return to the framework. The redundant time measurement could > > be removed, unless there is some obscure way of getting called on some > > platform that I am unable to figure out.) > > > > Tuukka Tikkanen (7): > > Cpuidle: rename expected_us to next_timer_us in menu governor > > Cpuidle: Use actual state latency in menu governor > > Cpuidle: Ensure menu coefficients stay within domain > > Cpuidle: Do not substract exit latency from assumed sleep length > > Cpuidle: Move perf multiplier calculation out of the selection loop > > Cpuidle: Deal with timer expiring in the past > > Cpuidle: poll state can measure residency > > > > drivers/cpuidle/driver.c | 2 +- > > drivers/cpuidle/governors/menu.c | 85 ++++++++++++++++++++++++-------------- > > 2 files changed, 54 insertions(+), 33 deletions(-) > > I'm queuing this series up for 3.15. Patch [6/7] dropped, because of the Len's objection. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.