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From Anthony Johnson <ans...@gmail.com>
Subject Re: Out of memory almost immediately after start
Date Tue, 29 Mar 2011 21:53:32 GMT
Hey Kirk,
    Just to clarify

If you set -Xms and -Xmx both to the same value which most people like
to do to prevent on-the-fly allocations and memory fragmentation then
you take that memory from being used as native memory.  A 3GB heap
leaves 1 GB for native at most on a 32 bit system.  This is one of the
major reasons that people run out of native space so quickly like the
parent is having is because they take so much memory away from native
space before the first thread is even started.

The fact that the 10th thread gets an error and thread creation is
fine after that does sound like some sort of OS or Java bug as sebb
mentioned.  Hopefully the parent can make sure that he is using the
most recent JVM and see if the problem still occurs.

Thanks,

Anthony



On Mon, Mar 28, 2011 at 8:51 PM, Kirk <kirk.pepperdine@gmail.com> wrote:
> -Xmx sets max Java heap size where as -Xms set min Java heap size. Java threads take
both Java heap and native stack space. Fiddling with these values is unlikely to have any
effect on the number of threads being started. 10 threads should start without issue unless
someone is consuming a ton of memory or the default JMeter memory settings have been fiddled
with (like stack size).
>
> Regards,
> Kirk
>
> On Mar 28, 2011, at 2:04 PM, Anthony Johnson wrote:
>
>> We just had a similar thread related to this, but the problem is that
>> Java itself does not have enough native memory left to create a
>> thread.
>>
>> This is going to be related to your -Xmx -Xms settings and the amount
>> of threads that you are asking JMeter to run.
>>
>> Try lowering your thread count, setting -Xms JVM setting and/or
>> lowering the -Xmx value to allow for more native memory.
>>
>> Their are other tricks as well, but the ones above should get you back on track.
>>
>> Good luck,
>>
>> Anthony
>>
>> On Mon, Mar 28, 2011 at 7:34 AM, Cor-Paul Bezemer <c.bezemer@tudelft.nl> wrote:
>>> I'm investigating a problem I have with one of my testcases and when I
>>> inspect the log file, I see the following happen:
>>>
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-2
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-6
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-8
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-10
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-1
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-4
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-3
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-5
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-7
>>> 2011/03/28 13:30:38 INFO  - jmeter.threads.JMeterThread: Thread started:
>>> Stepping Thread Group 1-9
>>> 2011/03/28 13:30:38 ERROR - jmeter.engine.StandardJMeterEngine: Uncaught
>>> exception:  java.lang.OutOfMemoryError: unable to create new native thread
>>>         at java.lang.Thread.start0(Native Method)
>>>         at java.lang.Thread.start(Unknown Source)
>>>         at
>>> org.apache.jmeter.engine.StandardJMeterEngine.run(StandardJMeterEngine.java:
>>> 484)
>>>         at java.lang.Thread.run(Unknown Source)
>>>
>>> So an outofmemory exception is thrown almost immediately after starting the
>>> tests... Does anyone have any idea what causes this?
>>> It doesn't really seem to affect the test run but I want to make sure it
>>> isn't.
>>>
>>> Thanks! CP
>>>
>>>
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>>>
>>
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>
>
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