Specifies for which processes tracing is to be enabled. This option accepts a comma separated list of triplets, each of the form
:<stop>:<incr>specifying the minimum and maximum rank and the increment to determine a set of processes (similar to the Fortran 90 notation). Ranks are interpreted relative to
MPI_COMM_WORLD, which means that they start with
0. The letter
Ncan be used as maximum rank and is replaced by the current number of processes. For example, to enable tracing only on odd process ranks, specify
PROCESS 0:N OFFand
PROCESS 1:N:2 ON.
A process that is turned off can later turn logging on by calling
VT_traceon()(and vice versa). Using
nodisables Intel Trace Collector for a process completely to reduce the overhead even further, but also so that even
VT_traceon()cannot enable tracing.
discardis the same as
no, so data is collected and trace statistics is calculated, but the collected data is not actually written into the trace file. This mode is useful if looking at the statistics is sufficient: in this case there is no need to write the trace data.