Re: [sensor-dev] Results of very simple performance test + reported Jamon values are false

[Jeroen B. <jbo...@xe...>]

Hi Age,

Sounds great, but I am not convinced.

How did you test the JAMon performance?
The JAMon page refers to com.jamonapi.TestClassPerformance, it also uses 
a monitor around the test with the loop (of 1.000.000 iterations),
the last code block:
        timingMon.start();
        test.factoryMonitor();
        log(timingMon.stop()); :

Gives me the next output:
----
Full Factory TimingMonitor()- uses cached version so doesn't create 
child monitors
    Monitor mon=MonitorFactory.start('pages.admin');
    mon.stop();
JAMon Label=pages.admin, Units=ms.: (Hits=2000000.0, Avg=7.0E-5, 
Total=140.0, Min=0.0, Max=16.0, Active=0.0, Avg Active=1.0, Max 
Active=1.0, First Access=Mon Mar 20 10:28:02 CET 2006, Last Access=Mon 
Mar 20 10:28:05 CET 2006)
It took 1594 ms.
----
The JAMon label Avg=7.0E-5 is bogus because of the clock resolution as 
you point out. However, the time all 1.000.000 iterations took is: 1594 ms.
This means 627.000 calls per second on my 5160 laptop with jdk 1.4.2.

So, I would say the numbers on the JAMon page are correct (405.000 
calls/s for jdk1.4). Agree?

Ciao,
Jeroen.

PS. I haven't had time to time Sensor yet.

Age Mooy wrote:

>Hi
>
>I did some extremely rudimentary performance overhead tests using the
>following code (snippet):
>
>============================
>
>parentTimer.start();
>
>for (int i = 0; i < 1000000; i++) {  // or 500000
>  timer.start();
>  timer.stop();
>}
>
>parentTimer.stop();
>
>=============================
>
>I consistently got performance of around 68000 start/stop operations
>per second (the average time for 500000 iterations was 7.4 seconds and
>the average time for 1000000 iterations was 14.6 seconds)
>
>I measured the total time of the parent timer since the time
>resolution of the VM/OS is not accurate enough in the 0 - 10 ms range.
>The total time of the timer that was being started and stopped in the
>loop consistently reports values about 3 times as fast, which would
>lead to performance of about 200000 iterations per second.
>
>Funnily enough that last number is prety close to the performance
>listed on the Jamon 2.0 page so I ran the Jamon 2.0 performance tests
>and got almost exactly the same performance as Sensor. Sensor was
>slightly faster on a 1.4 jdk.
>
>This means that the performance listed on the Jamon 2.0 website is not
>correct since they did not take the VM/OS timing resolution into
>account.
>
>Conclusion: Sensor does not seem to have any performance problems
>relative to Jamon and performs similar or better than Jamon 2.0.
>
>Age
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-- 
drs. Jeroen Borgers
Senior Consultant, SCJP, SCEA
Xebia IT Architects BV, Utrechtseweg 49, 1213 TL Hilversum, The Netherlands, www.xebia.com
office: +31(0)35-5381921, mobile: +31(0)6-30128951, jbo...@xe...