14 Feb
2023
14 Feb
'23
3:57 p.m.
On Fri, 10 Feb 2023 at 23:46, Fons Adriaensen <fons(a)linuxaudio.org> wrote:
On Thu, Feb 09, 2023 at 01:34:52PM +0100, Wim Taymans wrote:
You don't need to use polling with timerfd, just set the timeout
according to some clock,
add the timerfd to some poll loop and it wakes up on time. Very much
like how ALSA wakes
you up when a period expires.
Wim
real JACK is more mature and does things
differently (mostly device
wakeup with IRQ instead of timers)
The real difference between the two methods is 'sample count'
versus 'time' as the source of the event that starts a period.
I always wondered why one would use a timer, it just amounts
to polling. Suppose you look every 1 ms to check if there are enough samples for a period. That means you can be
up
to 1 ms late. Compare that to the period time of 1.33 ms
when using 64 samples / 48 kHz. Up to 3/4 of the available
time to compute a period could be lost...
Or am I missing something ?
Ciao,
--
FA