Using DTrace

The DTrace facility is a dynamic tracing framework for the Solaris 10 operating system that enables you to monitor JVM activity.

DTrace contains more than 30,000 probes and uses integrated user-level and kernel-level tracing to give you a view into your production system. You can also trace arbitrary data and expressions by using the D language, which is similar to C or awk. The DTrace facility also includes special support for monitoring the JVM, and enables you to watch your whole system and span outside the JVM.

DTrace is easiest to use with Java 6 because probes are built into the JVM. The facility also works with Java 1.4 and Java 5, but you must download JVM PI or JVM TI agents from the following URL:

https://solaris10-dtrace-vm-agents.dev.java.net/

The following example shows how to write a DTrace script.

Example 4–2 Example DTrace Script

#!/usr/sbin/dtrace -Zs 
#pragma D option quiet
hotspot$1::: 
{
  printf("%s\n", probename); 
}

In this example, you would replace $1 with the first argument to the script, which is the PID of the Java process you want to monitor. For example:

# ./all-jvm-probes.d 1234

The following table describes the commands you can use to enable different DTrace probes.

Because DTrace causes additional work in the system, enabling this facility affects system performance. The effect is often negligible, but can become substantial if you enable many probes with costly enablings.

Instructions for minimizing the performance effect of DTrace are provided in the “Performance Considerations” chapter of the Solaris Dynamic Tracing Guide.

For more information about DTrace, see /usr/demo/dtrace and man dtrace.