Average Processing Time Statistic Calculation

[karapirinc]

Average processing time calculation does not present actual average time.

tigase.stats.StatisticsInvocationHandler.Statistics#updateExecutionTime

public void updateExecutionTime(long executionTime) {
    executions_counter++;
    avgProcessingTime = (avgProcessingTime + executionTime) / 2;
}

Suppose that, there are 3 executions with 3, 5 and 10ms. Expected average processing time : (3 + 5 + 10) / 3 = 18 / 3 = 6ms Actual average processing time : ( (3 + 5) / 2 + 10 ) / 2 = 7ms

Over time gap between actual and expected times increases. Actual average processing time closer to the last value.

• Tigase version: 8.3.0

[woj-tek]

I think the confusion stems from the fact, that we are using "moving average" (with very small window). While it may seem "incorrect" in the whole execution period, it gives better indication if there was a spike in the processing time. See the example below: Processing Time	(moving) Average processing time	(Total) Average processing time
2
4	3	3
6	5	4
3	4	4
3	3	4
3	3	4
6	5	4
7	6	4
8	7	5
3	5	5
6	5	5
7	6	5
33	20	7
6333	3176	459
6	1591	429
3	797	402
2	400	379
2	201	358
77	139	343
8	73	326
4	39	311
7	23	297
2	12	284
444	228	291
6	117	279
3	60	269
3	32	259
3	17	250
3	10	241
3	7	233