116 lines
3 KiB
C
116 lines
3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <pthread.h>
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#include "uthash.h"
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#undef uthash_noexpand_fyi
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#define uthash_noexpand_fyi(tbl) fprintf(stderr,"warning: bucket expansion inhibited\n")
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#define LOOPS 100000
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typedef struct {
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int i;
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UT_hash_handle hh;
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} elt;
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elt *elts=NULL; /* this is our hash table which two threads will use */
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pthread_rwlock_t lock;
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void *thread_routine_r( void *arg ) {
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int i;
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long num_found=0;
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elt *e;
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for(i=0;i<LOOPS;i++) {
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if (pthread_rwlock_rdlock(&lock) != 0) {
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fprintf(stderr,"can't acquire read lock\n");
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exit(-1);
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}
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HASH_FIND_INT(elts, &i, e);
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if (e) num_found++;
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pthread_rwlock_unlock(&lock);
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}
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return (void*)num_found;
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}
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void *thread_routine_w( void *arg ) {
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int i;
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long num_deld=0;
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elt *e;
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for(i=0;i<LOOPS;i++) {
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if (pthread_rwlock_wrlock(&lock) != 0) {
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fprintf(stderr,"can't acquire write lock\n");
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exit(-1);
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}
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HASH_FIND_INT(elts, &i, e);
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if (e) {
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/* HASH_DEL(elts, e); */
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/* num_deld++; */
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} else {
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e = malloc(sizeof(elt));
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if (!e) exit(-1);
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e->i = i;
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HASH_ADD_INT(elts, i, e);
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}
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pthread_rwlock_unlock(&lock);
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}
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return (void*)num_deld;
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}
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int main() {
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unsigned i;
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long num_added=0;
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int status;
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pthread_t thread_r1,thread_r2,thread_w1,thread_w2;
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void *thread_result;
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elt tmp, *e;
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if (pthread_rwlock_init(&lock,NULL) != 0) {
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fprintf(stderr,"lock init failed\n");
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exit(-1);
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}
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if (( status = pthread_create( &thread_r1, NULL, thread_routine_r, NULL) )) {
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printf("failure: status %d\n", status);
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exit(-1);
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}
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if (( status = pthread_create( &thread_r2, NULL, thread_routine_r, NULL) )) {
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printf("failure: status %d\n", status);
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exit(-1);
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}
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if (( status = pthread_create( &thread_w1, NULL, thread_routine_w, NULL) )) {
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printf("failure: status %d\n", status);
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exit(-1);
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}
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if (( status = pthread_create( &thread_w2, NULL, thread_routine_w, NULL) )) {
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printf("failure: status %d\n", status);
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exit(-1);
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}
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status = pthread_join( thread_r1, &thread_result );
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printf("thread result: %d %ld\n", status, (long)thread_result);
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status = pthread_join( thread_r2, &thread_result );
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printf("thread result: %d %ld\n", status, (long)thread_result);
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status = pthread_join( thread_w1, &thread_result );
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printf("thread result: %d %ld\n", status, (long)thread_result);
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status = pthread_join( thread_w2, &thread_result );
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printf("thread result: %d %ld\n", status, (long)thread_result);
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i = HASH_COUNT(elts);
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printf("final count of items in hash: %u\n", i);
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if (pthread_rwlock_destroy(&lock) != 0) {
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fprintf(stderr,"lock destroy failed\n");
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exit(-1);
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}
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}
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