PetscLogEventRegister — PETSc 3.22.5 documentation

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# PetscLogEventRegister

Registers an event name for logging operations

## Synopsis

    #include "petscsys.h"
    PetscErrorCode PetscLogEventRegister(const char name[], PetscClassId classid, PetscLogEvent *event)

Not Collective

## Input Parameters

- name - The name associated with the event

- classid - The classid associated to the class for this event, obtain either with `PetscClassIdRegister()` or use a predefined one such as `KSP_CLASSID`, `SNES_CLASSID`, the predefined ones are only available in C code

## Output Parameter

- event - The event id for use with `PetscLogEventBegin()` and `PetscLogEventEnd()`.

## Example Usage

          PetscLogEvent USER_EVENT;
          PetscClassId classid;
          PetscLogDouble user_event_flops;
          PetscClassIdRegister("class name",&classid);
          PetscLogEventRegister("User event name",classid,&USER_EVENT);
          PetscLogEventBegin(USER_EVENT,0,0,0,0);
             [code segment to monitor]
             PetscLogFlops(user_event_flops);
          PetscLogEventEnd(USER_EVENT,0,0,0,0);

## Notes

PETSc automatically logs library events if the code has been configured with –with-log (which is the default) and -log_view or -log_all is specified. `PetscLogEventRegister()` is intended for logging user events to supplement this PETSc information.

PETSc can gather data for use with the utilities Jumpshot (part of the MPICH distribution). If PETSc has been compiled with flag -DPETSC_HAVE_MPE (MPE is an additional utility within MPICH), the user can employ another command line option, -log_mpe, to create a logfile, “mpe.log”, which can be visualized Jumpshot.

The classid is associated with each event so that classes of events can be disabled simultaneously, such as all matrix events. The user can either use an existing classid, such as `MAT_CLASSID`, or create their own as shown in the example.

If an existing event with the same name exists, its event handle is returned instead of creating a new event.

## See Also

Profiling, `PetscLogStageRegister()`, `PetscLogEventBegin()`, `PetscLogEventEnd()`, `PetscLogFlops()`, `PetscLogEventActivate()`, `PetscLogEventDeactivate()`, `PetscClassIdRegister()`

## Level

intermediate

## Location

src/sys/logging/plog.c

Index of all Profiling routines
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Index of all manual pages