Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030374Ab3HICHW (ORCPT ); Thu, 8 Aug 2013 22:07:22 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55846 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967597Ab3HIB7Y (ORCPT ); Thu, 8 Aug 2013 21:59:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeremy Eder , Len Brown , "Rafael J. Wysocki" Subject: [ 067/102] Revert "cpuidle: Quickly notice prediction failure in general case" Date: Thu, 8 Aug 2013 18:57:43 -0700 Message-Id: <20130809015025.996644747@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130809015010.208118575@linuxfoundation.org> References: <20130809015010.208118575@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3800 Lines: 109 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Rafael J. Wysocki" commit 228b30234f258a193317874854eee1ca7807186e upstream. Revert commit e11538d1 (cpuidle: Quickly notice prediction failure in general case), since it depends on commit 69a37be (cpuidle: Quickly notice prediction failure for repeat mode) that has been identified as the source of a significant performance regression in v3.8 and later. Requested-by: Jeremy Eder Tested-by: Len Brown Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpuidle/governors/menu.c | 35 +---------------------------------- 1 file changed, 1 insertion(+), 34 deletions(-) --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -34,7 +34,7 @@ static DEFINE_PER_CPU(struct hrtimer, menu_hrtimer); static DEFINE_PER_CPU(int, hrtimer_status); /* menu hrtimer mode */ -enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT, MENU_HRTIMER_GENERAL}; +enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT}; /* * Concepts and ideas behind the menu governor @@ -116,13 +116,6 @@ enum {MENU_HRTIMER_STOP, MENU_HRTIMER_RE * */ -/* - * The C-state residency is so long that is is worthwhile to exit - * from the shallow C-state and re-enter into a deeper C-state. - */ -static unsigned int perfect_cstate_ms __read_mostly = 30; -module_param(perfect_cstate_ms, uint, 0000); - struct menu_device { int last_state_idx; int needs_update; @@ -223,16 +216,6 @@ EXPORT_SYMBOL_GPL(menu_hrtimer_cancel); static enum hrtimer_restart menu_hrtimer_notify(struct hrtimer *hrtimer) { int cpu = smp_processor_id(); - struct menu_device *data = &per_cpu(menu_devices, cpu); - - /* In general case, the expected residency is much larger than - * deepest C-state target residency, but prediction logic still - * predicts a small predicted residency, so the prediction - * history is totally broken if the timer is triggered. - * So reset the correction factor. - */ - if (per_cpu(hrtimer_status, cpu) == MENU_HRTIMER_GENERAL) - data->correction_factor[data->bucket] = RESOLUTION * DECAY; per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_STOP; @@ -389,7 +372,6 @@ static int menu_select(struct cpuidle_dr /* not deepest C-state chosen for low predicted residency */ if (low_predicted) { unsigned int timer_us = 0; - unsigned int perfect_us = 0; /* * Set a timer to detect whether this sleep is much @@ -400,28 +382,13 @@ static int menu_select(struct cpuidle_dr */ timer_us = 2 * (data->predicted_us + MAX_DEVIATION); - perfect_us = perfect_cstate_ms * 1000; - if (repeat && (4 * timer_us < data->expected_us)) { RCU_NONIDLE(hrtimer_start(hrtmr, ns_to_ktime(1000 * timer_us), HRTIMER_MODE_REL_PINNED)); /* In repeat case, menu hrtimer is started */ per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_REPEAT; - } else if (perfect_us < data->expected_us) { - /* - * The next timer is long. This could be because - * we did not make a useful prediction. - * In that case, it makes sense to re-enter - * into a deeper C-state after some time. - */ - RCU_NONIDLE(hrtimer_start(hrtmr, - ns_to_ktime(1000 * timer_us), - HRTIMER_MODE_REL_PINNED)); - /* In general case, menu hrtimer is started */ - per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_GENERAL; } - } return data->last_state_idx; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/