[pulseaudio-discuss] What does pulseaudio use all the cpu-cycles for?

Colin Guthrie gmane at colin.guthr.ie
Sat Jul 30 06:42:59 PDT 2011

'Twas brillig, and Rémi Denis-Courmont at 30/07/11 10:35 did gyre and
> Le samedi 30 juillet 2011 12:03:29 Clemens Eisserer, vous avez écrit :
>> Hi,
>> Ever since Fedora switched to pulseaudio, I wonder what pulseaudio does
>> with all the cpu cycles it consumes.
>> When watching a mpeg4 video using mplayer, mplayer (using software decoder)
>> consumes only slightly more cpu time than pulseaudio simply mixing that
>> single sound-stream.
> I would guess it's resampling and/or mixing.

Yup, resampling and mixing mainly. You can configure PA to use a less
CPU intensive resampler (at the expense of sound quality) in daemon.conf.

Also, if your sound card is buggy and does not report accurate timing
information, it could be we do more work than we need to to keep it in

One of the main reasons to use PulseAudio is the power saving features.
You can save ~0.5 watts vs plain alsa by using the timer based
scheduling that PA uses by default. But this needs the drivers to behave
themselves :D



Colin Guthrie

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