On Sun, Sep 29, 2013 at 11:28:26AM +0200, Alex Holst wrote: > I'm looking for input on solving a long-standing issue with uaudio > playback on my desktop system. (http://mongers.org/openbsd/dmesg.fit) > > When playing local FLAC files or streaming ogg/mp3 through mpd (or > cvlc), I experience stuttering when system interrupts spike above 15% -- > the most reliable way I can reproduce this is by forcing a bit of disk > i/o.
do you know what causes these interrupts? is this the uaudio device? (ex try "systat -s1 vmstat") > Back in April I tried Alexandre's patch related to audio/midi interrupts > on mp kernels. This diff is now in, but something else is still causing interrupts to be missed on MP systems. Furthermore uaudio uses the usb sub-system which always grabs the kernel_lock and consequently will miss interrupts. > I also tried sndiod -r44100 -z2940 but neither made any > difference. > > Is the stuttering likely related to my hardware, is it a known problem > or is there something else I can try? uaudio driver is known to not work very well (lack of time to clean-up the driver). But I don't know if that's causing the stuttering you observe. There may be multiple causes :( You could try find the cause: - switch into using the GENERIC kernel and see if stuttering is affected - use trivial tools to play audio (eg. aucat -i foo.wav) during the tests. - does the "-mplay" option affect stuttering? if so the cause may be the uaudio driver. thanks -- Alexandre
