The virtual users that access
your web server require memory to prepare requests, send requests,
and receive responses. Because the amount of memory is not automatically
set on remote computers, you might receive an out-of-memory error.
To correct this situation, increase the memory allocation for that
computer.
About this task
If you receive an out-of-memory error when you run a test
or schedule, override the default amount of memory that is allocated
for that computer. To do this, set the RPT_VMARGS property, which
overrides RPT_DEFAULT_MEMORY_SIZE. After the first successful execution,
IBM® Rational® Performance Tester automatically
sets value for RPT_DEFAULT_MEMORY_SIZE, which represents the maximum
heap that will be specified by
Rational Performance Tester in
subsequent executions.
Note: Ensure there is at least one successful
execution after all locations are created so RPT_DEFAULT_MEMORY_SIZE
exists.
Tip: If you see out-of-memory issues,
it is a good practice to first check the javacore* file.
You can also look at the results and verify that the server is responding
correctly because many times errors can lead to excessive resource
consumption. You can also monitor memory usage with Task Manager or
other tools at varying user load levels such as 10, 50, 100, 500 or
1000 users and use that data to make an estimate of the memory needs
per virtual user and then project memory requirements for larger user
loads. In some cases the best solution is to add another agent.
Rational Performance Tester sets
heap size for RPT_DEFAULT_MEMORY_SIZE based on the bit-type of the
JRE:
- For 32-bit Java Runtime Environment (JREs), Rational Performance Tester sets
70% of the size of physical memory to RPT_DEFAULT_MEMORY_SIZE. Typically,
the maximum limit is set to 1200m.
- For 64-bit JREs, some workloads might perform better with a lesser
heap size than 70% of physical memory up to a maximum of 12000m.
What to do next
If you have increased the available
memory and you still receive out-of-memory errors, add more remote
computers for your user groups. For information about how to do this,
see
Running a user group at a remote location.