Hi Ivan, For both reasons actually. In order to better organise and collaborate my scripts, I keep different test sessions scripted in different test plans instead of different thread groups, even if I intend to run them simultaneously at some point. Its just a preference and not necessarily relevant. The biggest reason is indeed memory/cpu and garbage collection optimisation (but I run JMeter on very powerful machines lately, 32-64Gb boxes, so its easy to get tempted not to optimise the test bed, I wouldn't worry as much on 4Gb boxes for example). The scripts I've used in the last year were simple and are perform similarly when using one single large instance of JMeter or when using multiple instances. The performance optimisations that devs implemented in versions 2.8 and 2.9 are very helpful to this outcome. And I specifically needed to run a single instance that synchronised 18,000 threads to query the DB at roughly the same time. Accordingly to the monitoring system, most requests were received by the server within 5ms (considering the network latency were I tested, that's actually pretty good).
But in the past, I got into a lot of trouble by not validating my assumptions about how my script, itself, will perform. Its easier to predict how a small instance will perform even over very long periods of time (I test, monitor the machines and make sure that its how I presume, from time to time), and the behaviour is stable out of the box (very few changes needed to JVM parameters). I limit a single instance at 2Gb and CPU consumption is always predictable, 4-5% in my case, for each instance, including system + idle times. BTW, all the specifics mentioned were tested with non-GUI mode. Adrian S On Fri, Aug 23, 2013 at 1:01 PM, <[email protected]> wrote: > If I may ask, are the multiple Jmeter instances used: > - to run different test scripts > or > - because multiple VM use better the memory, with more frequent but less > blocking garbage collection... > > Thanks > Ivan > > -----Ursprüngliche Nachricht----- > Von: Adrian Speteanu [mailto:[email protected]] > Gesendet: Freitag, 23. August 2013 10:26 > An: JMeter Users List > Betreff: Re: Multiple Jmeter instance on same machine. > > Hi, > > I always run multiple instances on the same machines, but never tried it > with distributed mode. > > So, to the question of multiple instances: it is definitely possible and > scales quite nicely, but do be careful on memory allocation (the total -Xmx > in your configuration should not exceed the total memory that you have > available on the machine; leave some for the OS as well). > > Adrian S > > > On Fri, Aug 23, 2013 at 2:10 AM, Jomebrew <[email protected]> wrote: > > > I have used both but prefer GUI. I can run more instances when I use > > CLI mode. > > > > Cheers! > > > > > > On Thu, Aug 22, 2013 at 3:57 PM, hame <[email protected]> wrote: > > > > > Hey thanks for you quick response. even I thought that it will work > > > if I use GUI. > > > What if I don't want to use GUI and run in command line mode? will > > > it > > work? > > > > > > > > > > > > > > > On Thu, Aug 22, 2013 at 3:44 PM, Jomebrew <[email protected]> > wrote: > > > > > > > I run about four client instances on my server. Each one run is > > > graphical > > > > mode (against the advise of the message list) but my server has > > > > enough processor cores (8) and memory to handle the load. Memory > > > > used to be a problem but with later releases,much more CPU is > > > > being used. I have > > been > > > > running the same basic scripts since 2.6. > > > > > > > > Each instance runs two thread groups with 250 threads each for a > > > > total > > of > > > > 500 threads per instance. I use the aggregate report to monitor > > > > the > > load > > > > status. > > > > > > > > This all works well for me. > > > > > > > > Cheers! > > > > > > > > > > > > On Thu, Aug 22, 2013 at 3:40 PM, [email protected] > > > > <[email protected] > > > > >wrote: > > > > > > > > > Hi, > > > > > I want to run different test-plan by running multiple instances > > > > > of > > > > JMeter > > > > > on the same machine at the same time. Is it possible? > > > > > I know I can run multiple jmeter server instances on different > > > machine. > > > > > But > > > > > I am not sure whether I can run different instances of JMeter on > > > > > the > > > same > > > > > machine or not? Will it create any kind of interference for > > eachother? > > > > > > > > > > > > > > > > > > > > Thank you, > > > > > Rakesh > > > > > > > > > > > > > > > > > > > > ----- > > > > > Technical blog : code4reference > > > > > LinkedIn : Rakesh Kumar > > > > > -- > > > > > View this message in context: > > > > > > > > > > > > > > http://jmeter.512774.n5.nabble.com/Multiple-Jmeter-instance-on-same-ma > > chine-tp5717948.html > > > > > Sent from the JMeter - User mailing list archive at Nabble.com. > > > > > > > > > > ---------------------------------------------------------------- > > > > > ----- To unsubscribe, e-mail: [email protected] > > > > > For additional commands, e-mail: [email protected] > > > > > > > > > > > > > > > > > > > >
