You have several ways by which you can control the trace.
You can control the trace in several ways by using:
- The -Xtrace options when launching the JVM, including trace
trigger events
- A trace properties file
- com.ibm.jvm.Trace API
- JVMTI and JVMRI from an external agent
Note: - The specification of trace options
is cumulative. Multiple -Xtrace options are accepted
on the command line and they are processed left to right order. Each
one adds to the options set by the previous one (and to the default
options), as if they had all been specified in one long comma-separated
list in a single option. This cumulative specification is consistent
with the related -Xdump option processing.
- By default, trace options equivalent to the following
are enabled:
-Xtrace:maximal=all{level1},exception=j9mm{gclogger}
- To disable the defaults (or any previous -Xtrace options),
The -Xtrace keyword none also
allows individual tracepoints or groups of tracepoints to be specified,
like the other keywords. none is used in the
same way to disable a set of tracepoints as maximal, minimal and
the other options. However, instead of setting the maximal bit for
a tracepoint, it will clear all previously set bits for that tracepoint.
Thus -Xtrace:none=all
- Many diagnostic tools start a JVM. When using
the IBM_JAVA_OPTIONS environment variable trace to a file,
starting a diagnostic tool might overwrite the trace data generated
from your application. Use the command-line tracing options or add
%d, %p or %t to the trace file name to prevent this from happening.
See Detailed descriptions of trace options for
the appropriate trace option description.