On Fri, Oct 7, 2011 at 7:03 AM, <pierre-louis.bossart at linux.intel.com>wrote: > > > > I've attached the PA config files I am using, along with the log > > output(pulselog). The most suspicious thing in there is the failure to > > get > > RT scheduling. Is there something obviously wrong with the configs that > > would cause these numbers to be so high, or to prevent 10ms latency > > working? > > Hi Dylan, > Yes, without real-time scheduling it's unlikely that you would get > low-latency results. in your setup, everything is based on system timers > with ALSA interrupts disabled, if there's a delay in handling timer events > chances are you will see underruns, which results in a latency increase. > Is there any reason why this would fail on Chrome, usually this is only a > configuration issue? > This is just a configuration issue, I'll have to set up permissions for the default user to change setrlimit rtprio. I'll give that a try and see what happens. > > Looking at your log file, I think there's an issue with the buffer > settings. The requested latency is 20ms (tlength, total buffering), but at > the same time the minreq field is also set to 20ms. Minreq defines the > amount of data requested by PulseAudio to the client. You would think that > a double-buffering scheme is needed here. If the two values are equal, I > am not sure things would work well? Chances are that you fell in a corner > case where PulseAudio corrects the values you set to have the latency at > least twice the minreq value? > Makes sense, I'll take a look at what pacat is actually filling the buffer attributes with and see if I can track this down. > > Also in default.pa you load the alsa-sink/source by hand yet use > module-detect. This looks odd, it's either one or the other? > hand loading was just a quick hack to avoid using the alsa "default" interface which was going through dmix and wasting cycles. It's weird but I don't think it should hurt performance once it's up and running. thanks for the help Pierre, Dylan > -Pierre > > > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20111007/59c675af/attachment-0001.htm>
