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Move jack base latency computation out of delay() into graph() to save cycles.

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Jörn Nettingsmeier
2019-02-16 02:03:15 +00:00
parent bda8b99cda
commit 4751a4e1bc
1 changed files with 11 additions and 7 deletions
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audio_jack.c
+11 -7
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@@ -137,16 +137,22 @@ static int process(jack_nframes_t nframes, __attribute__((unused)) void *arg) {
static int graph(__attribute__((unused)) void * arg) { static int graph(__attribute__((unused)) void * arg) {
jack_port_get_latency_range(left_port, JackPlaybackLatency, &latest_left_latency_range); jack_port_get_latency_range(left_port, JackPlaybackLatency, &latest_left_latency_range);
jack_port_get_latency_range(right_port, JackPlaybackLatency, &latest_right_latency_range); jack_port_get_latency_range(right_port, JackPlaybackLatency, &latest_right_latency_range);
jack_latency = (latest_left_latency_range.max + latest_right_latency_range.max) / 2;
debug(1, "JACK graph reorder callback called. Current latencies to terminal downstream port:\n" debug(1, "JACK graph reorder callback called. Current latencies to terminal downstream port:\n"
"\tLmin = %d, Lmax = %d, Rmin = %d, Rmax = %d", "\tLmin = %d, Lmax = %d, Rmin = %d, Rmax = %d; jack base latency = %d",
latest_left_latency_range.min, latest_left_latency_range.max, latest_left_latency_range.min, latest_left_latency_range.max,
latest_right_latency_range.min, latest_right_latency_range.max); latest_right_latency_range.min, latest_right_latency_range.max,
jack_latency);
return 0; return 0;
} }
static void error(const char *desc) { debug(2, "jackd error: \"%s\"", desc); } static void error(const char *desc) {
debug(2, "JACK error: \"%s\"", desc);
}
static void info(const char *desc) { inform("jackd information: \"%s\"", desc); } static void info(const char *desc) {
inform("JACK information: \"%s\"", desc);
}
int jack_init(__attribute__((unused)) int argc, __attribute__((unused)) char **argv) { int jack_init(__attribute__((unused)) int argc, __attribute__((unused)) char **argv) {
config.audio_backend_latency_offset = 0; config.audio_backend_latency_offset = 0;
@@ -234,7 +240,6 @@ void jack_flush() {
} }
int jack_delay(long *the_delay) { int jack_delay(long *the_delay) {
jack_nframes_t base_latency;
// semantics change: we now look at the last transfer into the lock-free ringbuffer, not // semantics change: we now look at the last transfer into the lock-free ringbuffer, not
// into the jack buffers directly (because locking those would violate real-time constraints). // into the jack buffers directly (because locking those would violate real-time constraints).
// on average, that should lead to just a constant additional latency. the old comment still applies: // on average, that should lead to just a constant additional latency. the old comment still applies:
@@ -259,8 +264,7 @@ int jack_delay(long *the_delay) {
// debug(1,"delta: %" PRId64 " frames.",frames_processed_since_latest_latency_check); // debug(1,"delta: %" PRId64 " frames.",frames_processed_since_latest_latency_check);
// use the average of the left and right maximum latencies. if max is really different from min, // use the average of the left and right maximum latencies. if max is really different from min,
// there is an anomaly in the graph that we don't have any hope of fixing anyways // there is an anomaly in the graph that we don't have any hope of fixing anyways
base_latency = (latest_left_latency_range.max + latest_right_latency_range.max) / 2; *the_delay = jack_latency + audio_occupancy_now - frames_processed_since_latest_latency_check;
*the_delay = base_latency + audio_occupancy_now - frames_processed_since_latest_latency_check;
// debug(1,"reporting a delay of %d frames",*the_delay); // debug(1,"reporting a delay of %d frames",*the_delay);
return 0; return 0;
} }