2-pthreads/{hello/hello.c → hello_w/hello_w.c} RENAMED
@@ -1,24 +1,68 @@
1
  #include <pthread.h>
2
  #include <stdio.h>
 
 
 
3
 
4
  /*
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  int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
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  void* (*start_routine)(void*), void *arg);
7
  */
8
 
9
  void* run(void* data)
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  {
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  size_t thread_id = (size_t)data;
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- printf("Hellow from thread %zu\n", thread_id);
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  return NULL;
14
  }
15
 
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- int main(void)
17
  {
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- pthread_t thread;
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- pthread_create(&thread, NULL, run, (void*)13);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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  printf("Hello from main thread\n");
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- pthread_join(thread, NULL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
22
 
23
  return 0;
24
  }
1
  #include <pthread.h>
2
  #include <stdio.h>
3
+ #include <stdlib.h>
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+ #include <time.h>
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+ #include <unistd.h>
6
 
7
  /*
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  int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
9
  void* (*start_routine)(void*), void *arg);
10
  */
11
 
12
  void* run(void* data)
13
  {
14
  size_t thread_id = (size_t)data;
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+ printf("Hello from thread %zu\n", thread_id);
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  return NULL;
17
  }
18
 
19
+ int main(int argc, char* argv[])
20
  {
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+ #if defined(PRINT_ARGS)
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+ for ( int index = 0; index < argc; ++index )
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+ printf("%d[%s]\n", index, argv[index]);
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+ #endif
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+
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+ size_t thread_count = sysconf(_SC_NPROCESSORS_ONLN);
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+ if ( argc >= 2 )
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+ {
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+ // thread_count = strtoull(argv[1], NULL, 10);
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+ if ( sscanf(argv[1], "%zu", &thread_count) != 1 || thread_count == 0 )
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+ return (void)fprintf(stderr, "hello_w: error: invalid thread count: %s\n", argv[1]), 1;
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+ }
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+
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+ pthread_t* threads = (pthread_t*)malloc(thread_count * sizeof(pthread_t));
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+ if ( threads == NULL )
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+ return (void)fprintf(stderr, "hello_w: error: could not allocate memory for: %zu threads\n", thread_count), 2;
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+
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+ //int clock_gettime(clockid_t clk_id, struct timespec *tp);
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+ struct timespec start_time;
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+ clock_gettime(CLOCK_MONOTONIC, &start_time);
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+
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+ for ( size_t index = 0; index < thread_count; ++index )
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+ pthread_create(&threads[index], NULL, run, (void*)index);
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+
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  printf("Hello from main thread\n");
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+
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+ for ( size_t index = 0; index < thread_count; ++index )
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+ pthread_join(threads[index], NULL);
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+
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+ #if 0
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+ struct timespec {
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+ time_t tv_sec; /* seconds */
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+ long tv_nsec; /* nanoseconds */
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+ };
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+ #endif
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+
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+ struct timespec finish_time;
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+ clock_gettime(CLOCK_MONOTONIC, &finish_time);
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+
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+ double seconds = finish_time.tv_sec - start_time.tv_sec
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+ + (finish_time.tv_nsec - start_time.tv_nsec) * 1e-9;
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+
63
+ printf("Thread creation and join time: %.9lfs\n", seconds);
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+
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+ free(threads);
66
 
67
  return 0;
68
  }