Subject: [linux-audio-dev] Re: desktop and multimedia as an afterthought?
From: Takashi Iwai (tiwai_AT_suse.de)
Date: Tue Jul 13 2004 - 11:30:13 EEST
At Mon, 12 Jul 2004 17:24:58 -0700,
Andrew Morton wrote:
>
> I am deeply skeptical about claims that CPU scheduler changes make any
> difference. A scheduler change shouldn't improve responsiveness of
> !SCHED_OTHER tasks at all, so perhaps there are application priority
> inversion problems, or applications aren't setting SCHED_FIFO/RR correctly.
> I do not know.
Regarding the JACK problem, it seems that the incompatibility with
NPTL (SCHED_INHERIT is default) did wrong.
Taking a look through the thread, I feel that very different topics
are argued in the single "desktop" problem, namely, the interactivity
and the latency. The latter, the problem of real-time audio
(e.g. JACK), must be irrelevant with the CPU scheduler. It can
be fixed by detecting the too long critical sections, but the fix
won't always improve the interactivity.
OTOH, the interactivity can be, and should be improved somehow with
tuning of CPU scheduler. However, even about this word, we discuss
totally different meanings. For example, the GUI response and the
fluent audio/video playback. The improvement of the former doesn't
imply the improvement of the latter (often contradictorily)...
-- Takashi Iwai <tiwai_AT_suse.de> ALSA Developer - www.alsa-project.org
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