I'm sorry if this comes as double posting but my previous post somehow disappeared.
Looking at fork.c, I'm wondering why do I need to init PAPI twice? i.e. once in the parent thread and then again in the child thread?
My problem is this... I would like to fork a child and execute some benchmarks and collect data ONLY for those benchmarks executed inside the forked child.
Here's what I am doing right now:
- Code: Select all
int main(int argc, char* argv[], char** envp){
static char* bench;
pid_t pid;
int status, ret, i;
long long events[NUM_EVENTS];
int br_taken = PAPI_BR_TKN;
int br_exec = PAPI_BR_CN;
long long values[NUM_EVENTS];
for (i=0; i<NUM_EVENTS; i++){
values[i] = 0;
}
bench = argv[1];
printf("\nParent PID: %d\n", getpid());
//let's add events to count
events[0] = br_taken;
events[1] = br_exec;
//fork a child for the executable
if(fork() == 0){
//init PAPI for child
initialize_papi("forked PAPI init");
PAPI_reset(*events);
ret = PAPI_start_counters((int *) events, NUM_EVENTS);
if(ret != PAPI_OK){
printf("Starting Papi coutners failed: %d ", ret);
}
execve(bench, argv, envp);
}else{
wait(&status);
if (WEXITSTATUS(status) != 0)
err_message("WEXITSTATUS is :%d", &status);
ret =PAPI_read_counters(values, NUM_EVENTS);
if(ret != PAPI_OK) {
printf("reading values failed: %d", ret);
}
}
//terminate papi, release all resources
PAPI_shutdown();
printf("\n\ncount1 = %10llu and count2 =%10llu \n", values[0], values[1]);
}
am I doing something wrong here?