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From Michael Stover <mstov...@apache.org>
Subject RE: jmeter memory consumption
Date Thu, 01 Jul 2004 17:50:55 GMT
On Thu, 2004-07-01 at 12:26, Remedy QA wrote:
> I will try running without any listeners and see if it makes a big difference.  I had
planned to have several clients generating load and these wouldn't have listeners and then
a client with one user will have the listener. 
>  
> Well, I did try non-gui mode but some threads kept hanging. It didn't happen with gui
mode though.

Hanging threads could be any number of problems, such as server stopped
responding and the thread is waiting on a blocked socket, or an error or
some sort in shutting the thread down left it in a bad state, etc. 
There might be messages in JMeter's error logs.

>  
> Do you have plans to improve the jmeter performance?  

But you haven't indicated you're having a problem.  What you said is
that JMeter took up all the space you gave it, which it of course will,
but that does not mean it runs slow or breaks.  Does it run slow?  You
didn't say.

If you start your jvm with -Xms1280m, then the jvm grabs 1.28 gig of
heap space from the beginning.  And the GC doesn't feel compelled to do
wholesale cleanup as long as there's lots of spare room in the heap. 
And yes, JMeter is going to chew up bytes because every byte of response
data from you server has to go somewhere - ie into a byte array and then
tossed into the garbage, which GC isn't serious about cleaning up until
absolutely necessary.

I have run 500 threads on my machine with much less space without too
much trouble.  Not particularly accurate results, but with that much IO
going on through a cable modem, that's to be expected.

-Mike

> Everything else about Jmeter is great.  This is the only real blocker I have come across
so far.  
>  
> thanks,
> mabel
> 
> "BAZLEY, Sebastian" <sebastian.bazley@atosorigin.com> wrote:
> It would be useful to know if it is as hungry without the Aggregate
> Listeners.
> 
> Also, try running the same test in non-GUI mode. You could try this with a
> Summariser, if you want to keep some track of what is happening.
> 
> As the others have said, it is already capable of decent performance, but of
> course if we can find and fix some memory leaks, not many (*) would
> complain...
> 
> S.
> (*) except perhaps the chip industry!
> -----Original Message-----
> From: Peter Lin [mailto:woolfel@gmail.com]
> Sent: 01 July 2004 03:33
> To: JMeter Users List; mstover1@apache.org
> Subject: Re: jmeter memory consumption
> 
> 
> to my knowledge, even if you use a commercial product like mercury.
> You still can't simulate 250 threads from one system without it eating
> a ton of memory. In fact, I believe mercury doesn't recommend you try
> it, unless you're using a beefy dual or quad CPU server with 8Gb of
> RAM, Gigabit ethernet and Gigabit router.
> 
> in fact, since mercury prefers to save the results to a database,
> you'd have a hard time doing it from one system. Mercury happens to
> have a good reputation and is considered a reliable testing tool.
> 
> I've been able to go up to 75 threads with JMeter with decent
> performance. For more than 100 threads I always use multiple client
> machines.
> 
> peter
> 
> 
> On Wed, 30 Jun 2004 22:29:06 -0400, Michael Stover 
> wrote:
> > 
> > So what's the problem, exactly?
> > 
> > -Mike
> > 
> > On Wed, 2004-06-30 at 20:21, Remedy QA wrote:
> > > It seems Jmeter is a memory hogger. If given more memory, it will keep
> consuming. I am using JMeter nightly build of June 12.
> > >
> > > During my test run of approximately 50 minutes, with 250 virtual users
> on one GUI Jmeter client, it managed to consume about 1 GB of real memory.
> As the test continued, the memory just kept diminishing. The garbage
> collecting (minor collecting) happened about every 20 to 60 seconds. The
> CPU spikes happen when there are GCs.
> > >
> > > I also ran the same test on a machine with only 1 GB of RAM. When the
> test was over, real memory was at about 32mb.
> > >
> > > I tried with non-GUI mode but several threads hung and never was able to
> finish.
> > >
> > > So it seems that if I use a machine with more memory and give it a
> bigger heap, it just consumes as much as it can. I don't think 250 virtual
> users for the machine type I use is too much load. There must be something
> I am missing. Any help appreciated.
> > >
> > > I ran a test with the following configuration:
> > >
> > > Single JMeter Client on Windows 2000 Server, 2 GB RAM, single 2.8 Ghz
> Pentium 4 CPU. JDK 1.4.2_04
> > >
> > > JMeter JVM settings:
> > > set HEAP=-Xms1280m -Xmx1280m
> > > set NEW=-XX:NewSize=512m -XX:MaxNewSize=512m
> > > set DEBUG=-verbose:gc -XX:-PrintTenuringDistribution -XX:+PrintGCDetails
> -XX:+PrintGCTimeStamps -XX:+PrintGCApplicationConcurrentTime
> -XX:+PrintGCApplicationStoppedTime
> > >
> > > All other JVM settings are the defaults that came with jmeter.bat.
> > >
> > > JMeter output set to CSV, jmeter and jorphan logging set to warning.
> > >
> > > Jmeter script:
> > >
> > > Test Plan
> > > ThreadGroup - 250 virtual users, ramping up every 5 seconds. Loop
> once.
> > > Aggregate Listener
> > > Simple Controller
> > > 8 HTTP Requests in here
> > > 3 Aggregate Listeners in here
> > > Runtime Controller - 45 minutes total for all users.
> > > 33 HTTP Requests in here
> > > 2 Aggregate Listeners in here
> > > Simple Controller
> > > 2 HTTP Requests in here.
> > >
> > >
> > >
> > >
> > > ---------------------------------
> > > Do you Yahoo!?
> > > Yahoo! Mail is new and improved - Check it out!
> > --
> > Michael Stover 
> > Apache Software Foundation
> > 
> > ---------------------------------------------------------------------
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> > 
> >
> 
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-- 
Michael Stover <mstover1@apache.org>
Apache Software Foundation


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