[Tts-project] Bug#1022119: Wakes up every 1.5s even with no work to do

[Samuel Thibault]

Control: reassign -1 pulseaudio

Samuel Thibault, le jeu. 20 oct. 2022 15:02:09 +0200, a ecrit:
> Josh Triplett, le jeu. 20 oct. 2022 13:45:45 +0100, a ecrit:
> > sd_dummy seems to be waking up every 1.5s even when it has no work to
> > do.
> 
> I don't see that happening on my system. Could you run strace on it so
> we get to know what happens in your case? E.g.
> 
> strace -p $(pgrep sd_dummy)

Ah, -f is needed to see the thread started by pulseaudio.

(gdb) bt
#0  0x00007fb4fdefe32f in __GI___poll (fds=fds at entry=0x7fb4f40071a0, nfds=nfds at entry=2, timeout=timeout at entry=1500) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fb4fe0652e1 in poll (__timeout=1500, __nfds=2, __fds=0x7fb4f40071a0) at /usr/include/x86_64-linux-gnu/bits/poll2.h:39
#2  poll_func (ufds=0x7fb4f40071a0, nfds=2, timeout=1500, userdata=0x56184db546b0) at ../src/pulse/thread-mainloop.c:70
#3  0x00007fb4fe056fa4 in pa_mainloop_poll (m=m at entry=0x56184db545b0) at ../src/pulse/mainloop.c:863
#4  0x00007fb4fe057606 in pa_mainloop_iterate (m=m at entry=0x56184db545b0, block=block at entry=1, retval=retval at entry=0x0) at ../src/pulse/mainloop.c:945
#5  0x00007fb4fe0576b0 in pa_mainloop_run (m=0x56184db545b0, retval=retval at entry=0x0) at ../src/pulse/mainloop.c:963
#6  0x00007fb4fe0653b9 in thread (userdata=0x56184db54560) at ../src/pulse/thread-mainloop.c:101
#7  0x00007fb4fd5d433f in internal_thread_func (userdata=0x56184db5ad20) at ../src/pulsecore/thread-posix.c:81
#8  0x00007fb4fde8784a in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:442
#9  0x00007fb4fdf0b2cc in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

so that's coming from pulseaudio. The 1500 delay is most probably
coming from

./src/pulse/stream.c:#define AUTO_TIMING_INTERVAL_END_USEC (1500*PA_USEC_PER_MSEC)

I don't know why pulseaudio would be waking up every 1.5s even if the
speech module doesn't submit any audio.

Samuel