On 14 December 2011 22:20, Deepak Shetty <[email protected]> wrote:
> I think the original post mentioned that GC was not running.
>
> can you take a thread dump when there is a pause and see what the threads
> are waiting on?
>

I would also try running JMeter in non-GUI mode; GUI mode is very
expensive in resources.

Ensure all non-essential Listeners are disabled, see:

http://jmeter.apache.org/usermanual/best-practices.html#lean_mean

>
> On Wed, Dec 14, 2011 at 1:56 PM, Kirk <[email protected]> wrote:
>
>> might be GC.. me be that JMeter's threads are all hung up in your server
>> doing stuff.
>>
>> Regards,
>> Kirk
>> On Dec 14, 2011, at 10:35 PM, Robin D. Wilson wrote:
>>
>> > I have a marginally complicated test case that performs a 'registration'
>> on
>> > my site. It gets the home page, POSTS a form, gets the response, POSTS
>> > another form, gets that response, and then completes. The test runs fine
>> > with 100 threads, and 30000 iterations - IF I don't "Retrieve All
>> Embedded
>> > Resources from HTML Files". In this mode, I am really testing the
>> throughput
>> > of my 'tomcat' application, not the other elements of my system. (I'm
>> > assuming that the other elements are being retrieved from our Content
>> Data
>> > Network instead of our main system in this case.)
>> >
>> > If I enable the "Retrieve All Embedded Resources from HTML Files" flag,
>> and
>> > tune the test down to 10 threads with 3000 total iterations, I notice a
>> very
>> > strange behavior. The test runs along at a pretty good clip for the first
>> > ~600 iterations (about 1 min, 25 seconds into the run), and then it just
>> > stops making requests for about 35 seconds. Then, it picks back up again
>> and
>> > runs for another 1 m 25s, and then stops again for 35 seconds... (NOTE:
>> with
>> > the 10 threads, 3000 total iterations - but with "Retrieve All
>> Embedded..."
>> > disabled - I don't see the 'stop' behavior either - so it isn't caused by
>> > tuning it down...)
>> >
>> > I recently added the "Perfmon Metrics Collector" to the test script, so I
>> > could see if one of the servers was maxed out - but it looks like all the
>> > servers are idle during the 'stop' period. Likewise, I added the Perfmon
>> for
>> > the "localhost" (running the JMeter test) to see if it was swamped - but
>> it
>> > too is idle during the 'stop'. I swapped out our network switch (the test
>> > environment is on an isolated network switch) with a _much_ higher
>> capacity
>> > switch - in case there was a network issue, still no change.
>> >
>> > I'm running out of ideas for things to check - so I thought I'd ask you
>> guys
>> > if you have any suggestions of things I should look at.
>> >
>> > My system consists of:
>> >
>> >       WinXP - running JMeter 2.4.1 - driving the test script in GUI mode
>> >       Server 1 - running Red Hat Linux, with "Apache (2.2.21)" as the web
>> > server - using AJP Proxy to Server 2
>> >       Server 2 - running Red Hat Linux, with Tomcat 7.0.21 as the App
>> > Server - connecting through Hibernate to Server 3
>> >       Server 3 - running Red Hat Linux with MySQL 5.x as the DB Server
>> >
>> > All 4 machines are running on a private switched network (32Gbs
>> backplane).
>> >
>> > The requests are downloading about 3MB total (per thread per iteration)
>> over
>> > 4 main URL requests, and 30+ 'Retrieve All Embedded' requests.
>> >
>> > At first I thought it was the network - but the new switch seemed to deny
>> > that thought (the old switch had a much slower backplane). Also, I'm
>> having
>> > no trouble collecting the PerfMon data during the 'stop' period - so the
>> > network is still functioning just fine...
>> > Then I thought it might be garbage collection on the tomcat - but I
>> watched
>> > the gc.log - and it doesn't do any GCs during the 'stop' period.
>> > Then I thought it might be the garbage collection on the JMeter side, so
>> I
>> > started the JMeter.bat from a 'cmd' prompt with gc logging enabled - it
>> > doesn't do any GCs during the 'stop' period either.
>> >
>> > The apache, tomcat, and DB are all 'idle' (no CPU to speak of, no network
>> > I/O, no disk I/O, etc.) during the 'stop' period.
>> >
>> > The JMeter box (WinXP) is doing very little during that time too (I
>> > attribute the little bit of activity to displaying the PerfMon graphs,
>> and
>> > Remote Desktop display to my desktop computer)...
>> >
>> > --
>> > Robin D. Wilson
>> > Sr. Director of Web Development
>> > KingsIsle Entertainment, Inc.
>> > VOICE: 512-777-1861
>> > www.KingsIsle.com
>> >
>> >
>> >
>> >
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>>
>>
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