This is a note to let you know that I've just added the patch titled
cpuidle: menu: fixed wrapping timers at 4.294 seconds
to the 2.6.33-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.33.git;a=summary
The filename of the patch is:
cpuidle-menu-fixed-wrapping-timers-at-4.294-seconds.patch
and it can be found in the queue-2.6.33 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.33 longterm
tree,
please let <[email protected]> know about it.
>From 7467571f4480b273007517b26297c07154c73924 Mon Sep 17 00:00:00 2001
From: Tero Kristo <[email protected]>
Date: Thu, 24 Feb 2011 17:19:23 +0200
Subject: cpuidle: menu: fixed wrapping timers at 4.294 seconds
From: Tero Kristo <[email protected]>
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 <[email protected]>
Signed-off-by: Len Brown <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/cpuidle/governors/menu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -185,6 +185,7 @@ static int menu_select(struct cpuidle_de
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_de
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);
Patches currently in longterm-queue-2.6.33 which might be from
[email protected] are
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