On 10/05/07, Sonam Chauhan <[EMAIL PROTECTED]> wrote:
[...]

Out of curiosity, would having thread pools in JMeter help in this case?

Perhaps.

The main purpose of the threads is to simulate independent users, and
a pool  means the threads are no longer independent.

[The same applies to the JDBC pooling, which I think should be removed
- or at least made optional].


Kind regards,
Sonam Chauhan
--
Corporate Express Australia Ltd.
Phone: +61-2-93350725, Email: [EMAIL PROTECTED]
-----Original Message-----
From: sebb [mailto:[EMAIL PROTECTED]
Sent: Wednesday, 9 May 2007 7:52 PM
To: JMeter Users List
Subject: Re: maximum number of threads per JMeter instance

There is no documentation, because there is no fixed limit - it
depends on the test plan, OS, JVM, hardware, network etc..

The only way to determine the limit is to try.  For example, if it
works OK for a particular scenario with 10 threads but not with 15,
then the limit is somewhere between 10 and 15.

Having said that, 2000 or more threads is a pretty large number, so
I'm not entirely surprised that there are memory problems. Some OSes
have limits to the number of open sockets, even if memory is not a
problem.

That number of threads is also potentially a huge load on whatever
server is under test - do you really need to run with 7000 threads?

As a work-round:
- use non-GUI mode
- remove all but one listener
- use CSV output
- minimise assertions
- use multiple independent jobs, and combine the results.

On 09/05/07, Sonam Chauhan <[EMAIL PROTECTED]> wrote:
> Hi -
>
>
>
> Can someone point me to documentation on the maximum number of threads
a
> single JMeter instance can handle? (I cannot find this information on
> Google or the wiki.)
>
>
>
> I have a problem with a testcase that has a large number of threads -
it
> has 2 thread groups with 2000 and 5000 threads each. On a Windows XP
SP2
> system with 2GB of RAM, java.exe grows to about 350MB before throwing
> this exception:
>
> -------------------------
>
> Exception in thread "Thread-1" java.lang.OutOfMemoryError: unable to
> create new native thread
>
>        at java.lang.Thread.start0(Native Method)
>
>        at java.lang.Thread.start(Thread.java:574)
>
>        at
>
org.apache.jmeter.engine.StandardJMeterEngine.run(StandardJMeterEngine.j
> ava:387)
>
>        at java.lang.Thread.run(Thread.java:595)
>
> -------------------------
>
>
>
> The JMeter version is 2.1.1 and the Java version is "1.5.0_10"
>
> -------------------------
>
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_10-b03)
>
> Java HotSpot(TM) Client VM (build 1.5.0_10-b03, mixed mode)
>
> -------------------------
>
>
>
> I tried tweaking two JMeter run script settings: HEAP and NEW. I
started
> small, and increased the numbers proportionally up until Xmx=1024m but
> it was little use - the more I increased HEAP size, the faster I got
the
> outOfMemory errors.
>
>
>
> I also came across some interesting information here about the maximum
> number of threads per process:
>
>
> http://blogs.msdn.com/oldnewthing/archive/2005/07/29/444912.aspx
>
> I tried using '-Xss128k' to reduce stack size per Java thread, but
that
> did not help either.
>
>
>
> Kind regards,
>
> Sonam Chauhan
>
> --
>
> Corporate Express Australia Ltd.
>
> Phone: +61-2-93350725, Email: [EMAIL PROTECTED]
>
>
>
>

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