Re: [ck] Re: SD still better than CFS for 3d ?(was Re: 2.6.23-rc1)

Matthew Hawkins
2007-07-31T15:57:43Z

On 7/31/07, Miguel Figueiredo <elmig@debianpt.org> wrote:
> CFS does not requeue_task() on SCHED_YIELD (used by graphic drivers) as until
> 2.6.22 and -ck. Please try this hack [1] that makes -ck to behave like CFS
> then you are comparing apples to apples.

Hi Miguel,

I tested with sched_yield_ctl set to 1

2.6.22.1-ck+sched_yield_hack
0 51
1 51
2 51
3 46
4 38
5 38
6 38
7 30
8 27
9 22
10 20

After getting the numbers on all setups with the 10 loops still
running I went for a run around the map (I used the "aggressor" map,
if anyone cares). CFS was noticeably smoother (despite the small
framerate differences). ie CFS was bordering on barely playable,
whereas the above test it wasn't really playable (felt like playing on
a lagged server). Even plain -ck was better (going for a run, the FPS
jumped from ~2 to 15). I've noticed messing with sched_yield tends to
cause strange defects in the past...

--
Matt