Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965435Ab2EOCR7 (ORCPT ); Mon, 14 May 2012 22:17:59 -0400 Received: from mail1.windriver.com ([147.11.146.13]:53003 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964893Ab2EOCQ3 (ORCPT ); Mon, 14 May 2012 22:16:29 -0400 From: Paul Gortmaker To: , Subject: [34-longterm 036/179] cpuidle: menu: fixed wrapping timers at 4.294 seconds Date: Mon, 14 May 2012 22:12:12 -0400 Message-ID: <1337048075-6132-37-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.9.6 In-Reply-To: <1337048075-6132-1-git-send-email-paul.gortmaker@windriver.com> References: <1337048075-6132-1-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2095 Lines: 55 From: Tero Kristo ------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. ------------------- commit 7467571f4480b273007517b26297c07154c73924 upstream. Cpuidle menu governor is using u32 as a temporary datatype for storing nanosecond values which wrap around at 4.294 seconds. This causes errors in predicted sleep times resulting in higher than should be C state selection and increased power consumption. This also breaks cpuidle state residency statistics. cc: stable@kernel.org # .32.x through .39.x Signed-off-by: Tero Kristo Signed-off-by: Len Brown Signed-off-by: Paul Gortmaker --- drivers/cpuidle/governors/menu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index f8e57c6..0537437 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -185,6 +185,7 @@ static int menu_select(struct cpuidle_device *dev) int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY); int i; int multiplier; + struct timespec t; if (data->needs_update) { menu_update(dev); @@ -199,8 +200,9 @@ static int menu_select(struct cpuidle_device *dev) return 0; /* determine the expected residency time, round up */ + t = ktime_to_timespec(tick_nohz_get_sleep_length()); data->expected_us = - DIV_ROUND_UP((u32)ktime_to_ns(tick_nohz_get_sleep_length()), 1000); + t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC; data->bucket = which_bucket(data->expected_us); -- 1.7.9.6 -- 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/