Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [PATCH] 2.5.72 O(1) interactivity bugfix | Date | Thu, 19 Jun 2003 09:38:04 +1000 |
| |
On Thu, 19 Jun 2003 08:59, Andreas Boman wrote: > On Wed, 2003-06-18 at 18:43, Con Kolivas wrote: > > On Thu, 19 Jun 2003 03:59, Andreas Boman wrote: > > > On Wed, 2003-06-18 at 10:43, Con Kolivas wrote: > > > > --BEGIN PGP SIGNED MESSAGE-- > > > > Hash: SHA1 > > > > > > > > Hi Ingo, all > > > > > > > > While messing with the interactivity code I found what appears to be > > > > an uninitialised variable (p->sleep_avg), which is responsible for > > > > all the boost/penalty in the scheduler. Initialising this variable to > > > > 0 seems to have made absolutely massive improvements to system > > > > responsiveness under load and completely removed audio skips up to > > > > doing a make -j64 on my uniprocessor P4 (beyond which swap starts > > > > being used), without changing the scheduler timeslices. This seems to > > > > help all 2.4 O(1) based kernels as well. Attached is a patch against > > > > 2.5.72 but I'm not sure about the best place to initialise it. > > > > > > Applying this ontop of 2.5.72-mm1 causes more xmms/mpg321/ogg123 > > > skipping than with plain -mm1 here. make -j20 on my up athlon 1900+ > > > with 512M ram causes extreme skipping until the make is killed. With > > > plain -mm1 I may get _one_ skip at the very begining of a song during > > > make -j20 (about 50% of the time). Plain -mm1 stops skipping after > > > 10-15 sec of playback of a song, and even switching desktops after that > > > doesnt cause skips, with or without make -j20 running (switching > > > to/from desktops with apps like mozilla, evolution etc. will cause > > > skips during the first 10-15 sec of a song regardless what I do it > > > seems). > > > > > > Renicing xmms to -15 doesnt change anything with either kernel. > > > > Hmm. I got too excited with the fact it improved so much on the 2.4 O(1) > > Well, I got very exited when I saw your post ;) I guess this is a > problem all us UP desktop users would like too see solved. > > > kernels that I didn't try it hard enough on the 2.5 kernels. I have had > > people quietly telling me that it isn't uninitialised, but that I am > > simply resetting it with this patch on new forked processes. It seems the > > extra changes to the 2.5 scheduler make this patch make things worse? > > Yeah, I poked around a bit after I sent my earlier mail to see what may > be going on and noticed that too. (In activate_task() and sched_exit() > and some other place iirc) > > > I need more testing of the 2.4 one as well to see if it was just my > > combination of hardware and kernel that was better with this... > > I suspect that is the case, yes, or I got unlucky with mine since it was > extremely bad during the make -j. I'll see if I can get a 2.4.21-ck > patched up with some other things I need here, and try to reproduce my > results. That should tell us if it is infact scheduler differences or > our different setups.
I had another look at 2.5 and noticed the max sleep avg is set to 10 seconds instead of 2 seconds in 2.4. This could make a _big_ difference to new forked tasks if they all start out penalised as most non-interactive. It can take 5 times longer before they get the balance right. Can you try with this set to 2 or even 1 second on 2.5?
Con
- 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/
| |