2010/4/19 Lennart Poettering <mznyfn@xxxxxxxxxxx> > On Wed, 14.04.10 15:56, Wu Fengguang (fengguang.wu@xxxxxxxxx) wrote: > > > Hi Lennart, > > > > We found that pulseaudio eats CPU ~19% CPU time, a little more than > > mplayer when playing video. This is horrible for laptop batteries. > > This is not a particularly useful report. > > You know, this can have so many different reasons, the only thing I can > really say, is that you can rest assured that it is not supposed to eat > that much in normal use. > > The CPU usage of PA is primarily dependant of the latency requested by > the clients. Low latency means high CPU load. Lower latency means higher > CPU load. Try "pacmd list-sink-inputs" to figure out the latency the > various applications requested. > > Then there can be driver problems, where the timing information is not > entirely correct that ALSA passes on to, with the result that we get > dropouts where we shouldn't, with the results that we shorten our sleep > times, with the final effect that the CPU usage goes up. > > Of course, if PA is used resampling and suchlike is moved from the > clients into the sound server and hence will be added to its CPU > usage. And PA uses a better resampler by default than ALSA traditionally > did, hence the CPU use will be a bit higher than plain ALSA. > > And then of course, the CPU usage depends on the CPU used. Is this some > embedded hardware? > > In summary: if you want to know what is going on, you need a suitable > tool, like a profiler and do the dirty work to figure out what is going > on. Just saying "19%" is not helpful to figure out what is going on. > > On my machine here it uses 3% CPU while playing. > > > Can we make it just work -- in green CPU mode? > > Yes, sure. If you use "pacat" you can play audio with almost zero CPU > usage, because it is one of the few clients that actually asks for > sensible latency (2s), which allows us to minimize the wakeup intervals > to less than a second. > > > I can find many users > > complaining about this, and it seems like some fix is available in > > this link: > > https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/207135 > > Fix? Where? > > Lennart > > AFAIK , the CPU usage increase with the number of applications connected to PA server . If I run 4 instances of mplayer on Fedora 10 , the CPU usage will increase from 3% to 12% _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
