Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

Paul Davis
2004-10-29T14:51:44Z

>here's Rui's setup:
>
>| Note: all tests were carried out running jackd -v -dalsa -dhw:0
>| -r44100 -p128 -n2 -S -P, loaded with 9 (nine) fluidsynth instances,
>| on a P4@2.533Ghz laptop, against the onboard sound device
>| (snd-ali5451).
>
>i suspect this means there was playback only, no capture, and thus the
>capture/playback interrupt interaction cannot be the case, right?

ok, he used the -P flag which means playback only. so yes, the ALSA
backend would only have opened the playback stream.

oh, and i must correct what i said before. the ALSA backend will
typically be polling on *two* fd's. ALSA represents playback and
capture as different devices, so a default jackd will open both and
poll both of them. the backend will wait until they are both ready
(ie. the capture device has the correct amount of data, the playback
device has the correct amount of space).

--p