diff options
| -rw-r--r-- | src/latency.c | 50 | ||||
| -rw-r--r-- | src/latency.h | 10 |
2 files changed, 60 insertions, 0 deletions
diff --git a/src/latency.c b/src/latency.c index 14c4d39ff..185003c7d 100644 --- a/src/latency.c +++ b/src/latency.c @@ -122,6 +122,56 @@ int latencyResetEvent(char *event_to_reset) { return resets; } +/* ------------------------ Latency reporting (doctor) ---------------------- */ + +/* Analyze the samples avaialble for a given event and return a structure + * populate with different metrics, average, MAD, min, max, and so forth. + * Check latency.h definition of struct latenctStat for more info. + * If the specified event has no elements the structure is populate with + * zero values. */ +void analyzeLatencyForEvent(char *event, struct latencyStats *ls) { + struct latencyTimeSeries *ts = dictFetchValue(server.latency_events,event); + int j; + uint64_t sum; + + ls->all_time_high = ts ? ts->max : 0; + ls->avg = 0; + ls->min = 0; + ls->max = 0; + ls->mad = 0; + ls->samples = 0; + if (!ts) return; + + /* First pass, populate everything but the MAD. */ + sum = 0; + for (j = 0; j < LATENCY_TS_LEN; j++) { + if (ts->samples[j].time == 0) continue; + ls->samples++; + if (ls->samples == 1) { + ls->min = ls->max = ts->samples[j].latency; + } else { + if (ls->min > ts->samples[j].latency) + ls->min = ts->samples[j].latency; + if (ls->max < ts->samples[j].latency) + ls->max = ts->samples[j].latency; + } + sum += ts->samples[j].latency; + } + if (ls->samples) ls->avg = sum / ls->samples; + + /* Second pass, compute MAD. */ + sum = 0; + for (j = 0; j < LATENCY_TS_LEN; j++) { + int64_t delta; + + if (ts->samples[j].time == 0) continue; + delta = ls->avg - ts->samples[j].latency; + if (delta < 0) delta = -delta; + sum += delta; + } + if (ls->samples) ls->mad = sum / ls->samples; +} + /* ---------------------- Latency command implementation -------------------- */ /* latencyCommand() helper to produce a time-delay reply for all the samples diff --git a/src/latency.h b/src/latency.h index 1d21d5182..f28fce375 100644 --- a/src/latency.h +++ b/src/latency.h @@ -50,6 +50,16 @@ struct latencyTimeSeries { struct latencySample samples[LATENCY_TS_LEN]; /* Latest history. */ }; +/* Latency statistics structure. */ +struct latencyStats { + uint32_t all_time_high; /* Absolute max observed since latest reset. */ + uint32_t avg; /* Average of current samples. */ + uint32_t min; /* Min of current samples. */ + uint32_t max; /* Max of current samples. */ + uint32_t mad; /* Mean absolute deviation. */ + uint32_t samples; /* Number of non-zero samples. */ +}; + void latencyMonitorInit(void); void latencyAddSample(char *event, mstime_t latency); |