-XX:[+|-]PerfTool
This option enables or disables JIT support for the perf tool without affecting the existing Xjit options.
Restriction: Since this option creates a file that is used by the Linux® system profiler, perf, it applies only to Linux.
Syntax
-XX:[+|-]PerfTool
| Setting | Effect | Default |
|---|---|---|
-XX:+PerfTool |
Enable | |
-XX:-PerfTool |
Disable | yes |
Explanation
The -XX:+PerfTool option is a stand-alone alternative for the existing -Xjit:perfTool option. If multiple -Xjit options exist, only the last option takes effect. Therefore, if the -Xjit:perfTool option is added later, it overrides the existing -Xjit options. To overcome this issue, the XX:+PerfTool option enables JIT support for the perf tool without having any impact on the existing Xjit options. This enabling option creates a /tmp/perf-<pid>.map file that is used by the perf tool to map the samples in the JIT-compiled code to the corresponding Java method names.
To disable the JIT support for the perf tool, set the -XX:-PerfTool option on the command line.