Setting the Initial Maximum and Absolute Maximum Memory
This page descibes the memory management of Web Performance TrainerTM.
Simulating large numbers of virtual users takes a great deal of
memory, and since running out of memory can cause some operating
systems to crash, a great deal of effort has gone into controlling
the amount of memory Web Performance TrainerTM uses.
The default settings are to limit
the amount of memory that Web Performance TrainerTM can use to 64MB.
The program will not use more than this amount of memory total,
and will stop during a playback session if this limit is reached.
This is obviously a lower limit that is not valid for modern computers
with plenty of memory available. To increase this value, use the
following steps:
Windows:
1. Locate the file "Web Performance TrainerTM 2.1.lax"
in the directory where you installed the program.
2. Create a backup copy of the file.
3. Edit the file, looking for the two lines:
# LAX.NL.JAVA.OPTION.JAVA.HEAP.SIZE.INITIAL
# -----------------------------------------
lax.nl.java.option.java.heap.size.initial=33554432
# LAX.NL.JAVA.OPTION.JAVA.HEAP.SIZE.MAX
# -------------------------------------
lax.nl.java.option.java.heap.size.max=67108864
The values are the initial and
maximum number of bytes Web Performance TrainerTM is allowed to
use. You should set it to the maximum value of free memory you
have available on your computer to run applications without swapping.
The default maximum size is 64 megabytes, and the default initial
size is 32 megabytes.
The INITIAL size is really the initial maximum. Once memory usage passes that
value, it will incrementally bump the maximum until it reaches the MAX value above. Note that this can affect performance,
so you can should set the INITIAL and MAX values to be the same. The difference is that during a performance test,
if you reach the hard MAX size, the test will stop in the middle.
The following values are conservative
suggestions. Note that they are suggested values, and there are
many differences between computers, so you should monitor memory
usage of your computer, and if your computer starts to swap, i.e.
runs out of real memory, you should lower the memory usage of
the program.
| Total hardware Memory |
INITIAL (bytes) |
MAX (bytes) |
| 96 |
41943040 |
41943040 |
| 120 |
83886080 |
83886080 |
| 256 |
16772160 |
16772160 |
Solaris/Linux:
To modify
the amount of memory used by Web Performance TrainerTM edit the
file "wptrainer", and change the line:
MEMORY=64M
You can substitute
the 64M with the number of free megabytes of hardware memory you
have available.
Working Around Memory Limitations
If you're running out of memory, try the following things to reduce
your memory usage.
- Delete old Performance Statistics and Graphs
- Delete old Business Cases
- Start a new file, and import the business cases you're currently using.
- Check your operating system to see if there are any background processes
taking up memory.
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