Subject: [linux-audio-dev] new Linux-realtime project, includes realtime X11 too :-)
From: Benno Senoner (sbenno_AT_gardena.net)
Date: Thu Apr 20 2000 - 03:19:54 EEST
Hi,
I saw this on freshmeat today: (from a guy at AT&T)
http://www.uk.research.att.com/~dmi/linux-srt/
(read the thesis PS file, really lots of good stuff)
really nice stuff:
some of the highlights:
- QoS scheduler for rate monotonic tasks,
- X11 request prioritization !!
Basically if you run with realtime privileges, the X server (you have to run a
modified version), is changed to realtime scheduling too (on the fly),
plus it requests your X11 requests before processing other X11 clients.
That means if you have a video player running with realtime privileges, and
x11perf is running in background, you will still get the full framerate,
because the videoplayer's X11 requests get served with higher prioritiy than
the requests of other X11 clients.
What has this to do with audio ?
for example Terminator-X is very sensible to X11 stalls,
for example if there is heavy disk I/O going on in the background,
even with the lowlatency patches installed, and even if the audio doesn't stall,
you don't get nice results, since mouse events do not get delivered while the X
server is stalled. Therefore you hear very bursty pitch changes.
With that realtime X11 stuff, it would be smooth all the time.
That your GUI would not stall when doing heavy duty audio processing / HD
recording,
with sliders and faders, oscilloscopes, spectrum analyzers etc, running smoothly
all the time.
If that stuff can go into the mainstream XFree, then we are another step
close to the true media OS.
Benno.
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