Subject: Re: [linux-audio-dev] Re: sched_setscheduler question ...
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: Sun Jun 11 2000 - 01:34:41 EEST
>Basically, you can create sa.c files using sfront with the -playback
>(audio streaming for SAOL that has no real-time audio or control
>inputs) or -timesync (real-time systems that take audio and control
>input from a sound card, and use it to control the SAOL program).
OK, so to clarify a little bit: the SCHED_FIFO policy is for the
program produced by sfront, not for sfront itself, is that correct ?
>So, I'm now looking at the pros and cons of adding SCHED_FIFO and page
>locking for -timesync and -playback modes ... the biggest problem with
>-timesync now is the occassional daemon wake-up causing a click, which
>SCHED_FIFO seems to solve completely, so it seems worth pursuing so
>the saol.net folks can stop rebooting into single-user mode so often :-).
this seems unusual. people can run Csound without SCHED_FIFO and
without clicks under Linux, unless the computational load is high. is
that the situation you're describing ?
>I can't seem to duplicate this under OSS/Free using a Soundblaster PCI 128
>card -- basically, always in -timesync mode and for heavy-compute SAOL
>programs in -playback mode, write() is always called when there is at
>least one fragment ready for use, and so it seems like write() isn't
>blocking.
How many fragments do you request ?
Also, on an somewhat unrelated note: are you aware of
(1) ALSA's support for high-end soundcards, which OSS cannot
really support well because of API limitations
(2) The fact that high-end soundcards will violate some or all
of the assumptions that most Linux audio applications
seem to use (16 bit, stereo, interleaved sample streams) ?
It would be nice if sfront would produce code that could use ALSA on
this kind of soundcard.
--p
This archive was generated by hypermail 2b28 : Sun Jun 11 2000 - 02:11:05 EEST