Subject: Re: [linux-audio-dev] RTC Rate on Slower Machines
From: Billy Biggs (bbiggs_AT_DIV8.NET)
Date: Tue Feb 13 2001 - 00:58:06 EET
Tim Goetze (tim_AT_quitte.de):
> > Ok, so, I'll just default to 1024Hz.
>
> if you just wait for sync f8 to come in and then play, why would you
> need anything besides that? i mean, polling the MIDI in would suffice
> in this case, or am i misunderstanding something ...
ttrk supports both syncing to external MIDI and relaying that sync (so
I block read()'ing on the MIDI device to throttle the SCHED_FIFO
thread), or being the clock master (and throttling by read()'ing on
/dev/rtc). So, I need to use the rtc only in the second case.
> btw polling /dev/rtc @ 8192 kHz in an empty loop takes ~10 % cpu on a
> k6-2-400 and ~9 on a k6-3-450 and no clocks are dropped, just for
> reference.
Well that's not so bad. I don't mind my app taking up all the cpu, I
just care about when the sync doesn't work. 1024hz seems like a
reasonable requirement.
-- Billy Biggs bbiggs_AT_dumbterm.net http://www.billybiggs.com/ wbiggs_AT_uwaterloo.ca
This archive was generated by hypermail 2b28 : Tue Feb 13 2001 - 03:19:24 EET