start-stop.c

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// -*-Mode: C++;-*- // technically C99

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//***************************************************************************
//
// File:
// $HeadURL$
//
// Purpose:
// This file provides an API for the application to start and stop
// sampling with explicit function calls in the application source.
//
// Note:
// (1) The actions are process-wide.
//
// (2) The start and stop functions turn the sample sources on and off
// in the current thread.  The sources in the other threads continue
// to run but don't unwind and don't record samples.  Stopping
// sampling in all threads is more complicated because it would have
// to be done in a signal handler which can't really be done safely.
//
// (3) Sampling is initally on.  If you want it initially off, then
// set HPCRUN_DELAY_SAMPLING in the environment.
//
//***************************************************************************

#include <stdlib.h>

#include "sample_sources_all.h"
#include "start-stop.h"

static int sampling_is_active = 1;
static int dont_reinit = 0;


//***************************************************************************
// interface functions
//***************************************************************************

void
hpcrun_start_stop_internal_init(void)
{
  // Make sure we don't run init twice.  This is for the case that the
  // application turns sampling on/off and then forks.  We want to
  // preserve the state across fork and not reset it in the child.
  if (dont_reinit) {
    return;
  }
  if (getenv("HPCRUN_DELAY_SAMPLING") != NULL) {
    sampling_is_active = 0;
  }
  dont_reinit = 1;
}


int
hpctoolkit_sampling_is_active(void)
{
  return sampling_is_active;
}


void
hpctoolkit_sampling_start(void)
{
  sampling_is_active = 1;
  dont_reinit = 1;
  if (! SAMPLE_SOURCES(started)) {
    SAMPLE_SOURCES(start);
  }
}


void
hpctoolkit_sampling_stop(void)
{
  sampling_is_active = 0;
  dont_reinit = 1;
  if (SAMPLE_SOURCES(started)) {
    SAMPLE_SOURCES(stop);
  }
}


// Fortran aliases

// FIXME: The Fortran functions really need a separate API with
// different names to handle arguments and return values.  But
// hpctoolkit_sampling_start() and _stop() are void->void, so they're
// a special case.

void hpctoolkit_sampling_start_ (void) __attribute__ ((alias ("hpctoolkit_sampling_start")));
void hpctoolkit_sampling_start__(void) __attribute__ ((alias ("hpctoolkit_sampling_start")));

void hpctoolkit_sampling_stop_ (void) __attribute__ ((alias ("hpctoolkit_sampling_stop")));
void hpctoolkit_sampling_stop__(void) __attribute__ ((alias ("hpctoolkit_sampling_stop")));