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Merge sort with multi-threaded (without lock)
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#include <stdio.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#include <time.h> | |
#include <sys/time.h> | |
#include <pthread.h> | |
#include <errno.h> | |
unsigned long mem_size; | |
unsigned int malloc_cnt; | |
void* _malloc(size_t size){ | |
mem_size += size; | |
malloc_cnt ++; | |
return malloc(size); | |
} | |
void print(int* a, int n){ | |
int i=0; | |
printf("["); | |
for(i=0;i<n;i++){ | |
if(i>0) printf(","); | |
printf("%d",*(a+i)); | |
} | |
printf("]\n"); | |
} | |
double print_time(struct timeval *s, struct timeval *e){ | |
int si = (s->tv_sec%1000000)*1000+s->tv_usec/1000; | |
int ei = (e->tv_sec%1000000)*1000+e->tv_usec/1000; | |
return (double)(ei-si)/1000.0; | |
} | |
int* sample(int n){ | |
int* sample_data = (int*)malloc(sizeof(int)*n); | |
int i=0; | |
int j=0; | |
while(j<n){ | |
if(rand()%2){ | |
*(sample_data+j) = i; | |
j++; | |
} | |
if(rand()%100>0){ | |
i++; | |
} | |
} | |
return sample_data; | |
} | |
int* shuffle(int* data, int n, int* random_data){ | |
memcpy(random_data,data,sizeof(int)*n); | |
int s = rand()%n; | |
int i, d, tmp; | |
for(i=0;i<n;i++){ | |
d = rand()%n; | |
tmp = *(random_data+d); | |
*(random_data+d) = *(random_data+s); | |
*(random_data+s) = tmp; | |
s = d; | |
} | |
return random_data; | |
} | |
int assert(int* a, int* b, int n){ | |
if(memcmp(a,b,n)){ | |
return 0; | |
}else{ | |
return 1; | |
} | |
} | |
typedef struct { | |
int *data; | |
int n; | |
} merge_arg; | |
int th_count=0; | |
int th_max_count=2; | |
void* merge_sort(void* _merge_arg){ | |
merge_arg *arg = (merge_arg*)_merge_arg; | |
if(arg->n<=1) return NULL; | |
int *total = (int*)_malloc(sizeof(int)*arg->n); | |
int half = arg->n/2; | |
int *left = total; | |
int *right = left+half; | |
int i; | |
for(i=0;i<half;i++){ | |
*(left+i) = *(arg->data+i); | |
} | |
for(i=half;i<arg->n;i++){ | |
*(right+i-half) = *(arg->data+i); | |
} | |
int left_p=-1, right_p=-1; | |
pthread_t *left_merge, *right_merge; | |
merge_arg *left_arg = (merge_arg*)_malloc(sizeof(merge_arg)); | |
merge_arg *right_arg = (merge_arg*)_malloc(sizeof(merge_arg)); | |
left_arg->data = left; | |
left_arg->n = half; | |
right_arg->data = right; | |
right_arg->n = arg->n-half; | |
if(th_count<th_max_count){ | |
left_merge = (pthread_t*)_malloc(sizeof(pthread_t)); | |
if((left_p=pthread_create(left_merge,NULL,merge_sort,(void*)left_arg))==0) | |
th_count++; | |
else | |
merge_sort(left_arg); | |
}else{ | |
merge_sort(left_arg); | |
} | |
if(th_count<th_max_count){ | |
right_merge = (pthread_t*)_malloc(sizeof(pthread_t)); | |
if((right_p=pthread_create(right_merge,NULL,merge_sort,(void*)right_arg))==0) | |
th_count++; | |
else | |
merge_sort(right_arg); | |
}else{ | |
merge_sort(right_arg); | |
} | |
if(left_p==0) | |
pthread_join(*left_merge,NULL); | |
if(right_p==0) | |
pthread_join(*right_merge,NULL); | |
int left_idx=0; | |
int right_idx=0; | |
while(left_idx<half || right_idx<arg->n-half){ | |
if(left_idx == half){ | |
*(arg->data+left_idx+right_idx) = *(right+right_idx); | |
right_idx++; | |
}else if(right_idx == arg->n-half){ | |
*(arg->data+left_idx+right_idx) = *(left+left_idx); | |
left_idx++; | |
}else if( *(left+left_idx) < *(right+right_idx) ){ | |
*(arg->data+left_idx+right_idx) = *(left+left_idx); | |
left_idx++; | |
}else{ | |
*(arg->data+left_idx+right_idx) = *(right+right_idx); | |
right_idx++; | |
} | |
} | |
free(total); | |
if(left_p==0){ | |
free(left_merge); | |
free(left_arg); | |
} | |
if(right_p==0){ | |
free(right_merge); | |
free(right_arg); | |
} | |
return NULL; | |
} | |
void do_assert(int* sample_data, int* sorted_data, int n){ | |
if(assert(sample_data,sorted_data,n)){ | |
printf("Sorted check OK.\n"); | |
}else{ | |
print(sample_data,n>100?100:n); | |
print(sorted_data,n>100?100:n); | |
} | |
} | |
int main(int argc, char *argv[]){ | |
if(argc<2){ printf("Give # of samples.\n"); exit(1); } | |
if(argc>2) | |
th_max_count = atoi(argv[2]); | |
int n = atoi(argv[1]); | |
int *sample_data; | |
struct timeval s, e; | |
//srand((unsigned) time(NULL)); | |
srand(100); | |
sample_data = sample(n); | |
int* random_data = (int*)malloc(sizeof(int)*n); | |
shuffle(sample_data,n,random_data); | |
mem_size = 0; | |
malloc_cnt = 0; | |
merge_arg* arg = (merge_arg*)malloc(sizeof(merge_arg)); | |
arg->data = random_data; | |
arg->n = n; | |
gettimeofday(&s,NULL); | |
merge_sort(arg); | |
gettimeofday(&e,NULL); | |
printf("Merge sort with multi-thread: %.2lf sec.\n",print_time(&s,&e)); | |
do_assert(sample_data,random_data,n); | |
printf("mem_size = %luMB, malloc_cnt = %d\n",mem_size/(1024*1024),malloc_cnt); | |
printf("# of threads = %d\n",th_count); | |
return 0; | |
} |
Author
nishidy
commented
Dec 10, 2016
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