Centre Blaise Pascal » Bench4GPU

/******************************************************************************

* FILE: hello.c

* DESCRIPTION:

*   A "hello world" Pthreads program.  Demonstrates thread creation and

*   termination.

* AUTHOR: Blaise Barney

* LAST REVISED: 08/09/11

******************************************************************************/

#include <pthread.h>

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include <stdio.h>

#define NUM_THREADS        1024

struct thread_data

{

  int thread_id;

  unsigned int seed_w;

  unsigned int seed_z;

  unsigned long iterations;

  unsigned long inside;

};

struct thread_data thread_data_array[NUM_THREADS];

// Marsaglia RNG very simple implementation

#define znew  ((z=36969*(z&65535)+(z>>16))<<16)

#define wnew  ((w=18000*(w&65535)+(w>>16))&65535)

#define MWC   (znew+wnew)

#define SHR3  (jsr=(jsr=(jsr=jsr^(jsr<<17))^(jsr>>13))^(jsr<<5))

#define CONG  (jcong=69069*jcong+1234567)

#define KISS  ((MWC^CONG)+SHR3)

#define MWCfp MWC * 2.328306435454494e-10f

#define KISSfp KISS * 2.328306435454494e-10f

#define ITERATIONS 1000000000

int MainLoopGlobal(unsigned long iterations,unsigned int seed_w,unsigned int seed_z)

{

  unsigned int z=seed_z;

  unsigned int w=seed_w;

  unsigned long total=0;

  for (unsigned long i=0;i<iterations;i++) {

    float x=MWCfp ;

    float y=MWCfp ;

    // Matching test

    unsigned long inside=((x*x+y*y) < 1.0f) ? 1:0;

    total+=inside;

   }

  return(total);

}

void *MainLoopThread(void *threadarg)

{

  int taskid;

  unsigned long iterations,total=0;

  unsigned int z,w;

  struct thread_data *my_data;

  my_data=(struct thread_data *) threadarg;

  taskid = my_data->thread_id;

  iterations = my_data->iterations;

  z = my_data->seed_z;

  w = my_data->seed_w;

  printf("Hello World! It's me, thread #%ld, with seeds (%ld,%ld) and %ld !\n", taskid,z,w,iterations);

  for (unsigned long i=0;i<iterations;i++) {

    float x=MWCfp ;

    float y=MWCfp ;

    // Matching test

    unsigned long inside=((x*x+y*y) < 1.0f) ? 1:0;

    total+=inside;

  }

  my_data->inside=total;

  printf("Thread %ld done, found %ld inside.\n",taskid,total);

  pthread_exit((void*) my_data);

}

int main(int argc, char *argv[])

{

  pthread_t threads[NUM_THREADS];

  pthread_attr_t attr;

  int *taskids[NUM_THREADS];

  int rc, t, sum;

  unsigned long num_threads,iterations;

  sum=0;

  void *status;

  iterations=atol(argv[1]);

  num_threads=atoi(argv[2]);

  printf("Number of threads defined to %ld\n",num_threads);

  printf("Number of iterations defined to %ld\n",iterations);

  /* Initialize and set thread detached attribute */

  pthread_attr_init(&attr);

  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);

  for(t=0;t<num_threads;t++) {

    thread_data_array[t].thread_id = t;

    thread_data_array[t].iterations = iterations/num_threads;

    thread_data_array[t].seed_w = (t+1)<<4;

    thread_data_array[t].seed_z = (1048576*(t+1))>>4;

    thread_data_array[t].inside = 0;

    printf("Creating thread %d\n", t);

    rc = pthread_create(&threads[t], &attr, MainLoopThread, (void *)

                        &thread_data_array[t]);

    if (rc) {

      printf("ERROR; return code from pthread_create() is %d\n", rc);

      exit(-1);

    }

  }

  /* Free attribute and wait for the other threads */

  pthread_attr_destroy(&attr);

  for(t=0; t<num_threads; t++) {

    rc = pthread_join(threads[t], &status);

    if (rc) {

      printf("ERROR; return code from pthread_join() is %d\n", rc);

      exit(-1);

    }

    printf("Main: completed join with thread %ld having a status of %ld\n",

           t,(long)status);

  }

  for(t=0;t<num_threads;t++) {

    printf("Return to main with %ld thread, %ld inside\n",

           t,thread_data_array[t].inside);

  }

  printf("Main: program completed. Exiting.\n");

  pthread_exit(NULL);

}