Introduction » Tracing

Trace distributed events.

The optional trace component vt::trace::Trace, accessed via vt::theTrace() builds a distributed trace of events, including VT handlers, user events, and MPI invocations via the PMPI interface. It outputs Projections log and sts files to enable performance analysis after execution.

To enable tracing at runtime, the trace component must be enabled at compile time with cmake. To enable tracing pass the cmake flag: -Dvt_trace_enabled=1

Tracing Specification File

In order to customize when tracing is enabled and disabled, a trace specification file can be passed to vt via a command-line flag: --vt_trace_spec --vt_trace_spec_file=filename.spec.

For details about vt's Specification File see Spec File

Incremental Trace Output

The trace events can be configured to be saved to the file in the incremental matter. To configure the interval of the flushes use the --vt_trace_flush_size=X parameter. The X stands for the number of trace events before the next flush.