From: Tero Kristo Date: Thu, 24 Feb 2011 15:19:23 +0000 (+0200) Subject: cpuidle: menu: fixed wrapping timers at 4.294 seconds X-Git-Tag: v2.6.35.14~123 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=857053c1d4fcba46f8fdfcbc4926c1e70757d4a5;p=thirdparty%2Fkernel%2Fstable.git cpuidle: menu: fixed wrapping timers at 4.294 seconds 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. Signed-off-by: Tero Kristo Signed-off-by: Len Brown Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 1b128702d300b..fa0787bb82515 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -236,6 +236,7 @@ static int menu_select(struct cpuidle_device *dev) int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); int i; int multiplier; + struct timespec t; if (data->needs_update) { menu_update(dev); @@ -250,8 +251,9 @@ 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);