One small note - a very important time is the "Max response time" - IMHO
it's even more important than the average response time, because it
can mean "lost customers" ( who will wait 10 secs to order from your site
:-).
HelloWorldServlet is a very bad test case, it uses Locales and that's
something very slow ( plus un-wanted disk access, etc).
It would be also interesting to measure individual servlet API calls, like
getParameter() -
that's a place where most of the tunning will probably go in tc3 at least.
Costin
>
> Here's the data I collected after running new, slightly modified, scripts
> (see attached) for which RequestInfoExample is requested by ab 100,000
> times on a Celeron 400Mz, 256MB SD100 memory, WD Caviar disk, Redhat6.1,
> with almost nothing else going on:
>
> C T X Conn Proc %Busy Overhead
>T-Overhead CPU/req
> secs reqs/sec ms avg CPU CPU min secs
> secs
> ms
>
> 1 2912.778 34.33 0 28 100 0.87 52.2
> 2860.578 0.0286
> 10 1495.122 66.88 0 149 100 0.92 55.2
> 1439.922 0.0144
> 20 1488.695 67.17 0 297 100 0.98 58.8
> 1429.895 0.0143
> 30 1503.032 66.53 0 450 100 1.12 67.2
> 1435.832 0.0144440 1591.704 62.83
> 0 636 100 1.31 78.6 1513.104 0.0151
>
> The earlier results involving the HelloWorldExample servlet were affected
> by variability which I think/hope is averaged out by the large number of
> requests made.
> The disk, as expected shows only about 1.8 requests per second, and is
> not the bottleneck anyway (as expected).
>
> My earlier results concerning HelloWorldExample were based on a smaller N
> and were not adjusted to account for CPU overhead. I'll re-run them ASAP.
>
> In the earlier results, thread queue locking was observed. Craig noted
> that the number of background threads is set to 75 in the config file.
> With that in mind, I made sure that the ab script ran with 70 or fewer
> concurrent requests. Here's what happened:
>
> catalina_log*.txt shows "HttpProcessor starting background
> thread[8080][i]" where i runs from 0/1 up to 50.
>
> catalina.out contains a full thread dump (50 on down), one of which
> involves the message "Waiting to be notified HttpProcessor[8080][43]".
> This appears to be the result of a segmentation violation involving
> HttpProcessor[8080][50] that is also reported. Of course, ab barfs from C
> = 50 onward. As I recall, SEGV was also the cause of the thread dump when
> I ran HelloWorldExample. So, the thread dump seems to be a repeatable
> phenomena (on my machine), apparently a function of N & C.
>
> QUESTION 1: Does segmentation violation occur on other machines? If so,
> is it a problem? If not, why not?
>
> QUESTION 2: What do the thruput and average processing times mean? Are
> they "good", "bad", or what?
>
> QUESTION 3: Since the scripts can be modified to run any servlet, how
> about a "realistic" one as Costin suggested in his ApacheCon presentation
> (unless the examples are "representative").
>
> (Hack) Roy
>
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