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perf: combine duplicate Knuth/Welford recursive mean

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Daniel Agar 2020-08-28 13:00:48 -04:00 committed by Beat Küng
parent 172a4e3557
commit fe391c0af8
1 changed files with 1 additions and 25 deletions
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26
src/lib/perf/perf_counter.cpp
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@ -239,30 +239,7 @@ perf_end(perf_counter_t handle)
struct perf_ctr_elapsed *pce = (struct perf_ctr_elapsed *)handle;
if (pce->time_start != 0) {
int64_t elapsed = hrt_absolute_time() - pce->time_start;
if (elapsed >= 0) {
pce->event_count++;
pce->time_total += elapsed;
if ((pce->time_least > (uint32_t)elapsed) || (pce->time_least == 0)) {
pce->time_least = elapsed;
}
if (pce->time_most < (uint32_t)elapsed) {
pce->time_most = elapsed;
}
// maintain mean and variance of the elapsed time in seconds
// Knuth/Welford recursive mean and variance of update intervals (via Wikipedia)
float dt = elapsed / 1e6f;
float delta_intvl = dt - pce->mean;
pce->mean += delta_intvl / pce->event_count;
pce->M2 += delta_intvl * (dt - pce->mean);
pce->time_start = 0;
}
perf_set_elapsed(handle, hrt_elapsed_time(&pce->time_start));
}
}
break;
@ -284,7 +261,6 @@ perf_set_elapsed(perf_counter_t handle, int64_t elapsed)
struct perf_ctr_elapsed *pce = (struct perf_ctr_elapsed *)handle;
if (elapsed >= 0) {
pce->event_count++;
pce->time_total += elapsed;