HPjmeter 4.3 User's Guide

Table 3 Supported -Xeprof options (continued)

The default value for this option is enable. Another way to disable inlining is

to collect the profile data while running the VM in interpreted mode (-Xint).

Enable/disable the profiling intrusion estimation.ie=yes|no

ie=yes, the default value, specifies that the profiler estimates the profiling

intrusion and writes the estimated values to the profile data file. HPjmeter uses

this data to compensate for intrusion, which means that the estimated intrusion

is subtracted from the CPU times before they are presented to the user. Disabling

intrusion estimation slightly reduces the size of the data files, but will also disable

the intrusion compensation feature. This option has no impact on the actual

profiling overhead.

Profiling with Zero Preparation

Zero preparation profiling is a feature of the HP JDK/JRE 5.0.04. It is started from the command

line by sending a signal to the JVM to start eprof. Engaging zero preparation profiling may have

a short term impact on application performance as the JVM adjusts to the demands of performing

dynamic measurements.

To collect profiling data without interrupting your application, do the following from the command

line:

1. Confirm that a HP JDK/JRE 5.0.04 or later is running the application that you want to profile,

and that no -Xeprof option has been specified.

2. Find the process ID of the running Java application.

3. Start the profiling interval: send a signal to the JVM by typing:

kill -USR2 pid

You will see the following message:

eprof: starting profiling

Let the profiling collection generated by the JVM continue for the length of time that you think

will be meaningful.

4. Stop the profiling interval by sending the same signal to the JVM:

kill -USR2 pid

You will see the following message:

eprof: terminating profiling

writing profile data to ./filename.eprof

You can now open the saved file in the HPjmeter console and view the collected metrics.

NOTE: For the signal to be captured by the JVM, you must either be logged in as root, or you

must be the user who started the JVM.