Re: glitch1 results - 2.6.21.3-cfs-v15

From: Ingo Molnar
Date: Tue Jun 05 2007 - 15:20:57 EST



* Bill Davidsen <davidsen@xxxxxxx> wrote:

> I have added cfs15 to the chart at
> www.tmr.com/~davidsen/sched_smooth_05.html and updated the source of
> the test at www.tmr.com/~public/source if anyone wants to run test on
> their hardware.

thanks!

> I feel that on my hardware cfs-13 was the smoothest for this test and
> for watching videos. Even relatively light load:
> nice -10 make -j4 -s
> of a kernel would cause jumps on the video, gears or youtube.

ah, found this bug i think! Does the patch below fix it for you and does
it bring back v13's smoothness for the reniced kernel build?

Ingo

Index: linux/kernel/sched_fair.c
===================================================================
--- linux.orig/kernel/sched_fair.c
+++ linux/kernel/sched_fair.c
@@ -385,6 +374,7 @@ static void enqueue_sleeper(struct rq *r
* during the whole sleep period:
*/
delta_fair = div64_s(delta_fair * load, load + p->load_weight);
+ delta_fair = div64_s(delta_fair * p->load_weight, NICE_0_LOAD);

prev_runtime = p->wait_runtime;
__add_wait_runtime(rq, p, delta_fair);
-
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