2007-06-04 21:56:16

by Bill Davidsen

[permalink] [raw]
Subject: glitch1 results - 2.6.21.3-cfs-v15

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

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.

--
Bill Davidsen <[email protected]>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot


2007-06-05 19:20:56

by Ingo Molnar

[permalink] [raw]
Subject: Re: glitch1 results - 2.6.21.3-cfs-v15


* Bill Davidsen <[email protected]> wrote:

> I have added cfs15 to the chart at
> http://www.tmr.com/~davidsen/sched_smooth_05.html and updated the source of
> the test at http://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);