ps_homeworks/dn2/server_a.c

#include<stdio.h>
#include <pthread.h> 
#include <omp.h>
#include <stdlib.h>
#include <unistd.h>

#define N_THREADS 1
#define N_STEPS 200
#define N_NUMBERS_CALCULATED 100000

pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
pthread_spinlock_t alive_threads_lock;
pthread_spinlock_t produced_numbers_lock;

int amicable_numbers[N_NUMBERS_CALCULATED];
long produced = 0;
int threads_alive = 0;

int calculate_amicable_number(int number) {
    for(int i=1; i< number; i++){
        if(number % i == 0){
            number = number + i;
        }
    }
    return number;
}

void *calculate_amicable_number_invterval(void * arg) {
	int *myrank = (int *)arg;
	long mystart = (int)(N_NUMBERS_CALCULATED/ (double)N_THREADS * *myrank);
	long myend = (int)(N_NUMBERS_CALCULATED / (double)N_THREADS * (*myrank + 1));
  
  for(int i = mystart; i < myend; i++) {
    amicable_numbers[i] = calculate_amicable_number(i);
  }

  return NULL;
}

int not_all_numbers_calculated() {
  int ret = 0;
  pthread_spin_lock(&produced_numbers_lock);
  if(produced < N_NUMBERS_CALCULATED)
    ret = 1;
  pthread_spin_unlock(&produced_numbers_lock); 
  return ret;
}

int is_there_space_for_new_thread() {
  int ret = 0;
  pthread_spin_lock(&alive_threads_lock);
  if (threads_alive < N_THREADS)
    ret = 1;
  pthread_spin_unlock(&alive_threads_lock);
  return ret;
}

int main() {
	pthread_spin_init(&alive_threads_lock, PTHREAD_PROCESS_PRIVATE);
	pthread_spin_init(&produced_numbers_lock, PTHREAD_PROCESS_PRIVATE);
	pthread_t t[N_THREADS];
	int p[N_THREADS];

	double dt = omp_get_wtime();

	for (int i = 0; i<N_THREADS; i++)
	{
		p[i] = i;
		pthread_create(&t[i], NULL, calculate_amicable_number_invterval, (void *)&p[i]);
	}

	for (int i = 0; i<N_THREADS; i++)
		pthread_join(t[i], NULL);
  
	dt = omp_get_wtime() - dt;
  
  for(int i = 0; i < N_NUMBERS_CALCULATED; i++){
    printf("%d, ", amicable_numbers[i]);
  }

	printf("\nExecution time: %lf\n",  dt);
  return 0;

  /// 10 000 korakov
  /// 1 THREAD: 14.173247
  /// 2 THREADS: 10.877419, speedup: 1.3029972459459362
  /// 4 THREADS:  6.838137, speedup: 2.0726766661738423
  /// 8 THREADS:  5.327306, speedup: 2.66049049932555
  /// 16 THREADS: 3.964736, speedup: 3.5748274286106314
}