Testcase for PAPI deadlock in _papi_hwi_lookup_or_create_cpu()

papi_test.c

// compile with -lpapi -fopenmp
#define _GNU_SOURCE

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <papi.h>
#include <assert.h>
#include <omp.h>
#include <sched.h>

#define errorExit(status, expected) if(status != expected){fprintf(stderr, "error: %s:%d:%s: %d/%d\n", __FILE__, __LINE__, __FUNCTION__, status, expected); exit(1);}

#define PAPI_errorExit(status, expected) if(status != expected){fprintf(stderr, "error: %s:%d:%s: %s\n", __FILE__, __LINE__, __FUNCTION__, PAPI_strerror(status)); exit(1);}

int eventSet = PAPI_NULL;

void add_events(){
  char *eventNames = getenv((const char*)"PAPI_EVENTS");
  char *eventNamesCopy = (char*)calloc(1, strlen(eventNames)+1);
  strcpy(eventNamesCopy, eventNames);

  printf("eventNames: %s\n", eventNames);

  char *result = 0;
  char delim[] = ",";
  int papi_error;
  
  result = strtok(eventNamesCopy, delim);
  while(result){
    int event;
    papi_error = PAPI_event_name_to_code(result, &event);
    PAPI_errorExit(papi_error, PAPI_OK);

    papi_error = PAPI_add_event(eventSet, event);
    PAPI_errorExit(papi_error, PAPI_OK);
    
    result = strtok(0, delim);
  }

  int numEvents = PAPI_num_events(eventSet);

  if(numEvents <= 0){
    fprintf(stderr, "error: expected one or more events\n");
    exit(1);
  }

  printf("added %d events\n", numEvents);

  papi_error = PAPI_reset(eventSet);
  PAPI_errorExit(papi_error, PAPI_OK);

}

void func(){
  uint64_t iterations = 2e9;
  volatile uint64_t i;
  printf("iterations: %lu\n", iterations);
  for(i = 0; i < iterations; i++);
}

void init_counters(){
  int papi_error;
  papi_error = PAPI_create_eventset(&eventSet);
  PAPI_errorExit(papi_error, PAPI_OK);
  
  papi_error = PAPI_assign_eventset_component(eventSet, 0);
  PAPI_errorExit(papi_error, PAPI_OK);

  //! apparently need root for this
  PAPI_cpu_option_t cpu_opt;
  cpu_opt.eventset = eventSet;
  cpu_opt.cpu_num=0;

  //! @todo PAPI deadlock here
  papi_error = PAPI_set_opt(PAPI_CPU_ATTACH, (PAPI_option_t*)&cpu_opt);
  PAPI_errorExit(papi_error, PAPI_OK);

  /*! sched_setaffinity() works on perf_event_system_wide.c only
      because it also uses CPU attachment through PAPI
  */

#if 0
  cpu_set_t mask;
  CPU_ZERO(&mask);
  CPU_SET(0, &mask);
  if(sched_setaffinity(0, sizeof(mask), &mask) < 0){
    fprintf(stderr, "set affinity failed\n");
    exit(1);
  }
#endif
  
  add_events(eventSet);
}

void start_counters(){
  int papi_error;
  papi_error = PAPI_start(eventSet);
  PAPI_errorExit(papi_error, PAPI_OK);
}

void stop_counters(){
  int numEvents = PAPI_num_events(eventSet);
  if(numEvents <= 0){
    fprintf(stderr, "error: expected one or more events\n");
    exit(1);
  }
  long_long *values = (long_long*)calloc(numEvents, sizeof(long_long));
  int papi_error;
  papi_error = PAPI_stop(eventSet, values);
  PAPI_errorExit(papi_error, PAPI_OK);

  int *events = (int*)calloc(numEvents, sizeof(int));
  papi_error = PAPI_list_events(eventSet, events, &numEvents);
  PAPI_errorExit(papi_error, PAPI_OK);

  int i;
  char name[1024];
  for(i = 0; i < numEvents; i++){
    papi_error = PAPI_event_code_to_name(events[i], name);
    PAPI_errorExit(papi_error, PAPI_OK);
    printf("%s\t", name);
  }
  printf("\n");
  for(i = 0; i < numEvents; i++)
    printf("%lld\t", values[i]);
  printf("\n");
}

int main(int argc, char ** argv){
  int papi_error = PAPI_library_init(PAPI_VER_CURRENT);
  PAPI_errorExit(papi_error, PAPI_VER_CURRENT);

  papi_error = PAPI_thread_init(&omp_get_thread_num);

  papi_error = PAPI_set_granularity(PAPI_GRN_SYS);
  PAPI_errorExit(papi_error, PAPI_OK);

  papi_error = PAPI_set_domain(PAPI_DOM_USER);
  PAPI_errorExit(papi_error, PAPI_OK);
  
  init_counters();

  start_counters();
  func();
  stop_counters();
  
  PAPI_shutdown();
  
  return 0;
}