Re: [patch] sched: yield debugging

Tim Chen
2007-08-01T22:47:09Z

On Tue, 2007-07-31 at 22:33 +0200, Ingo Molnar wrote:

> ok, good! Could you try the updated debug patch below? I've done two
> changes: made '1' the default, and added the
> /proc/sys/kernel/sched_yield_granularity_ns tunable. (available if
> CONFIG_SCHED_DEBUG=y)
>
> Could you try to change the yield-granularity tunable and see which
> value gives the best performance? A value of '100000' should in theory
> give the current (80% degraded) volanomark performance, the default
> value should give the above '20% down' result. The question is, is '20%
> down' the best we can get out of it? Does larger/smaller
> yield-granularity help perhaps? You can change it to any value between
> 100 usecs and 1 second.
>

Turning up the granuality helped. Here's the data I got
for Volanomark performance relative to 2.6.22
Granuality
1000000000 (max) 9% down
800000000 8% down
80000000 13% down
8000000 20% down
100000 56% down

Tim