'Twas brillig, and Raymond Yau at 21/04/10 01:30 did gyre and gimble:
2010/4/19 Daniel Chen seven.steps@gmail.com
but, like Lennart suggests, these are by no means *caused* by PulseAudio.
Best, -Dan
There are other factor affecting CPU usage significantly
- the number of pulseaudio clients connected to PA server (i.e. number of
audio stream need to be mixed ) 2) the accuracy of system timer and the clock of the sound chip 3) the latency requirement of the different PA clients 4) the resampling method 5) the cpu loading of the system 6) the period time/period size selected by PA server to configure the alsa driver
why do you ruled out the cause ?
If you use "pacat" you can play audio with almost zero CPU
usage
do you get the zero CPU usage in Ubuntu 9.04/Ubuntu 9.10 with pacat on your machines ?
The pacat support for proper latency adjustment is only available in more recent PA versions (with some , so chances are the older distros wont have them (although I believe a 9.10 version of 0.9.21+stable-queue exists somewhere.
These commits from stable-queue are certainly needed:
commit 19fa81bf1375032cb1a27c7715a28a52b238d4cb Author: Lennart Poettering lennart@poettering.net Date: Thu Feb 18 01:54:51 2010 +0100
pacat: always fully fulfill write requests
Make sure we always fulfill write requests from the server. If we don't the server won't ask us again and playback will stay stuck.
https://tango.0pointer.de/pipermail/pulseaudio-discuss/2010-February/006611....
and this one (although it's not problematic for playback):
commit b2e9fb6f6e12a3eab8a41c67017507e60d616e2a Author: Lennart Poettering lennart@poettering.net Date: Sun Feb 21 21:09:26 2010 +0100
pacat: pass buffer_attr to recording streams too
Pointed out by Colin Guthrie.
https://tango.0pointer.de/pipermail/pulseaudio-discuss/2010-February/006698....