External reviewer correctly identified that the +73 ring-buffer
commit didn't fix the symptom but the architecture is still
right. We need to distinguish two possible causes:
(a) Producer task isn't running (or running too rarely) so
ring stays underfilled.
(b) Producer IS running but fill_buffer returns zeros most of
the time (AudioHandler stuck in buffering_samples state
or no packets reaching it).
The +73 render-side diagnostic was insufficient: we logged
underruns + peak_out_i16 but not what the producer was
actually pushing. This commit adds producer-side metrics
rolled up every 5 s (250 ticks at 20 ms):
Producer task:
producer_ticks : timer firings (= ~250 per 5 s window;
fewer = tokio scheduler stalled)
produced_chunks : pushes into ring (= ticks - drops)
fill_buffer_calls : AudioHandler queries
fill_buffer_zero_returns : ticks where scratch came back all
zeros (no decoded content to play)
ring_full_drops : ticks where ring was full and we
skipped the push
ring_min/max_samples : depth envelope across window
ring_min/max_ms : same in milliseconds
window_peak_f32 : max scratch sample across window
window_rms_f32 : RMS of all scratch samples across
window
Render callback (per-100-callback as before, plus new fields):
ring_avail_before : Consumer::slots() before this read
(= how many samples were sitting in
the ring at callback entry)
read_frames : samples successfully popped
zero_filled : samples zero-filled because ring
was empty (= num_frames - read_frames)
underruns / underrun_samples / peak_out_i16 / clip_count_i16
: as before
Reading the next iteration's log:
If producer_ticks << 250 per 5 s window:
tokio scheduler isn't running the task fast enough.
Move producer to its own dedicated runtime, or use
std::thread + std::sync::mpsc + std::thread::sleep
instead of tokio.
If producer_ticks ~= 250 AND fill_buffer_zero_returns is
high (most ticks return silence):
AudioHandler isn't decoding packets fast enough OR is
stuck buffering. Bug is upstream in protocol layer
packet delivery or AudioHandler's jitter state machine.
The ring buffer architecture cannot fix this.
If producer_ticks ~= 250 AND fill_buffer_zero_returns is
low AND ring_min_ms stays >100ms AND underruns are low BUT
consumer's peak_out_i16 is still 0:
Something is wrong between push and pop. Lock-free
ring corruption, or wrong stride.
Pure diagnostic. No behavioural change beyond the logging.
Producer scratch envelope scan is O(scratch.len()) = 1920
samples per 20 ms tick = ~96k iterations/sec on the audio
producer thread \u2014 negligible CPU.
Build counter 73 -> 74.
EdisonJwa
a9aa19ecdd