Messages in this thread | | | Subject | Re: SD still better than CFS for 3d ?(was Re: 2.6.23-rc1) | From | Kasper Sandberg <> | Date | Tue, 31 Jul 2007 01:46:04 +0200 |
| |
On Sun, 2007-07-29 at 19:06 +0200, Ingo Molnar wrote: > * Kasper Sandberg <lkml@metanurb.dk> wrote: > > > Im still not so keen about this, Ingo never did get CFS to match SD in > > smoothness for 3d applications, where my test subjects are quake(s), > > world of warcraft via wine, unreal tournament 2004. [...] > > here's an update: checking whether Wine could be a factor in your > problem i just tested latest CFS against latest SD with a 3D game > running under Wine: v2.6.22-ck1 versus v2.6.22-cfsv19 (to get the > most comparable kernel), using Quake 3 Arena Demo under Wine (0.9.41). > Here are the results in a pretty graph: > > http://people.redhat.com/mingo/misc/cfs-vs-sd-wine-quake.jpg > > or, in text: > > 2.6.22-ck1 2.6.22-cfs-v19 > ------------------------ ------------------------ > quake + 0 loops | 41 fps quake + 0 loops | 41 fps > quake + 1 loop | 3 fps quake + 1 loop | 41 fps > quake + 2 loops | 2 fps quake + 2 loops | 32 fps > quake + 3 loops | 1 fps quake + 3 loops | 24 fps > quake + 4 loops | 0 fps quake + 4 loops | 20 fps > quake + 5 loops | 0 fps quake + 5 loops | 16 fps > > Quake3-under-Wine behavior under SD/-ck: framerate breaks down massively > during any kind of load. The game is completely unusable with 1 CPU loop > running already!
I run quake3 natively, ut2k4 natively, and world of warcraft under wine.
> > Quake3-under-Wine behavior under CFS: framerate goes down gently with > load, gameplay remains smooth. Framerate is still pretty acceptable and > the game is playable even with a 500% CPU overload. The graph looks good > and the framerate reduction goes roughly along the expected 1/n > 'fairness curve' - so it all looks pretty healthy. [Note: quake3 keeps > its fully 41 fps even with 1 competing loop running on the CPU due to > "sleeper fairness".] > > [ i've re-tested this using other SD and ck versions and other CFS > versions such as v2.6.23-rc1 and the results are the same. To get the > fps result i started a simple game scene: Single Player / > Q3DM1 / I Can Win, turned on the fps display of Quake3, and did not > move the player at all, just looked at the framerate that is > displayed. (i also tried other scenes and other gameplay sections and > they all behave consistently with the above results.) The system was > otherwise completely idle. While i trust these numbers take them with > a grain of salt, i'm obviously not neutral in this thing :-) ] > > so Kasper, i'll definitely need your help in tracking down your 3D > smoothness problem under CFS. I have the feeling that it could be some > odd factor that only hits your system, and once we've tracked that down > there will be a simple solution that does not affect the totality of the > scheduler. So far only you have reported any 3D game smoothness problem > against recent CFS versions. (all 3D feedback has been positive, and > that includes a number of gamers as well. Most of the 3D smoothness > problems were fixed in CFS v13..v15 and it has not been reported to have > regressed since then.)
I believe the responsibility for my situation is both IO and cpu load. i dont know why SD does this. my test is to make spamasassin process mails while i have these applications running(and wine is most sensitive, the difference is almost negligable in the native applications, but very much noticable with wine+wow)
could perhaps be filesystem related, i have my maildir(extremely large) on reiserfs, and /home on xfs. what my mail client will do is download mail, spamasassin it(loading database from home), then it will put to imap server placing it on reiserfs, and then a "local" copy in my home.
while i only see the spamasassin thread as hogging cpu, i suspect IO is also to blame.
> > Ingo
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |