Messages in this thread | | | Date | Tue, 13 Jan 2004 11:48:58 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: SCHED_SOFTRR patch (memory lock?) |
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On Thu, 7 Aug 2003, Roger Larsson wrote:
> On Thursday 07 August 2003 18.31, Takashi Iwai wrote: > > At Thu, 7 Aug 2003 16:59:03 +0100, > > > > Daniel Phillips wrote: > > > > Under 2.6.0-test1 based kernels I have experienced quite a lote of > > > > drop-outs with XMMS playing mp3's with a moderate load, however, when > > > > run as root (with SCHED_RR) I encountered no drop-outs at all. When > > > > using SOFTRR under I had very choppy playback when the machine was > > > > under load. It was a constant jittering more than intermittent > > > > drop-outs. > > > > > > According to me, this should not happen, since your cpu usage is well > > > below what is supposed to be the cutoff for the realtime slice. I've > > > only seen one report like yours, where SOFTRR isn't working as intended. > > > On the other hand, I've missed a lot of lkml traffice lately, so there > > > could be more. > > > > looking at the source code of xmms and found that xmms OSS output > > plugin behaves differently if the process is SCHED_RR. > > when xmms is started with SCHED_RR, it won't create an (another) audio > > thread. perhaps this explains also the difference found in some > > cases. > > > > well, i'm not 100% sure about this theory, now needs to practice :) > > please try to turn off the check of SCHED_RR in > > xmms/Output/OSS/audio.c, something like: > > > > realtime = xmms_check_realtime_priority(); > > > > replaced with > > > > realtime = 0; > > Another possibility - will XMMS lock its memory from swapping when running as > root? (Or are there any special allocation/IO rule for root?)
Gee, it was 100F last time I saw this thread :-) Yes, xmms behave in two completely different ways depending on the fact that it is or it is not running RR. With RR it writes directly to the dsp, while w/out it creates a thread that handles an output buffer. Then thread then does write to the dsp when the buffer has something to be written.
- Davide
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