Messages in this thread | | | Date | Thu, 2 Oct 2003 02:41:02 +0200 | Subject | Re: Linux 2.6.0-test6 | From | Pedro Larroy <> |
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On Mon, Sep 29, 2003 at 12:55:12PM -0400, Ed Sweetman wrote: > Nick Piggin wrote: > > > > > >Rob Landley wrote: > > > >>On Sunday 28 September 2003 02:03, Con Kolivas wrote: > >> > >>>On Sun, 28 Sep 2003 11:27, Linus Torvalds wrote: > >>> > >>>>from Andrew Morton. Most notably perhaps Con's scheduler changes that > >>>>have been discussed extensively and made it into the -mm tree for > >>>>testing. > >>>> > >>>For those who are trying this for the first time, please note that the > >>>scheduler has been tuned to tell the difference between tasks of the > >>>_same_ > >>>nice level. This means do NOT renice X or it will make audio skip unless > >>>you also renice your audio application by the same amount. Lots of > >>>distributions have done this for the old 2.4 scheduler which could not > >>>treat equal "nice" levels as differently as the new scheduler does > >>>and 2.6 > >>>shouldn't need special treatment. > >>> > >>>So for testing note the following points: > >>> > >>>Make sure X is NOT reniced to -10 as many distributions are doing. > >>>Some shells spawn processes at nice +5 by default and this will make > >>>audio > >>>apps suffer. > >>>Make sure your hard disk, graphics card and audio card are performing at > >>>equal standard to your 2.4 kernel (ie dma is working, graphics is fully > >>>accelerated etc). > >>> > >> > >>I.E. with your new scheduler, priority levels actually have enough of > >>an effect now that things that aren't reniced can be noticeably > >>starved by things that are. > >> > > > >AFAIK, Con's scheduler doesn't change the nice implementation at all. > >Possibly some of his changes amplify its problems, or, more likely they > >remove most other scheduler problems leaving this one noticable. > > > >If X is running at -20, and xmms at +19, xmms is supposed to still get > >5% of the CPU. Should be enough to run fine. Unfortunately this is > >achieved by giving X very large timeslices, so xmms's scheduling latency > >becomes large. The interactivity bonuses don't help, either. > > > > there are 40 positions between -20 and 19, that doesn't equal 5% steps. > They don't even refer to % of cpu. If i nice a process to -20 it > doesn't get a given percentage of cpu just because it's -20. I may have > other processes at -20 as well. If you nice something to -20 and it is > actually using that cpu then things that are +19 shouldn't run and wont > run. If I nice -20 vmstat 1, it's not going to starve xmms (or any > better audio player). -20 means starve all and it should do that when > it actually makes use of the resources. >
Why not run xmms with SCHED_RR or SCHED_FIFO?
Regards.
Pedro.
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