统计代码耗时长短

最新推荐文章于 2024-08-24 01:59:33 发布

原创最新推荐文章于 2024-08-24 01:59:33 发布 · 660 阅读

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#include <stdio.h>
#include <sys/time.h>
#include <time.h>

#define TEST_MAX_SIZE (10)
struct timeval testTime[TEST_MAX_SIZE];
int	testCount[TEST_MAX_SIZE];

struct timeval tmpTime[TEST_MAX_SIZE], tmpTime2;
#define TIME_TEST(index,...) 							\
 do 													\
 {														\
	gettimeofday(&tmpTime[index], NULL);				\
 	__VA_ARGS__											\
 	gettimeofday(&tmpTime2, NULL);						\
 	timeSub(&testTime[index], &tmpTime[index]);			\
 	timeAdd(&testTime[index], &tmpTime2);				\
 	testCount[index]++;									\
 } while (0);


void timeAdd(struct timeval *t1, struct timeval *t2) {
	t1->tv_sec += t2->tv_sec;
	t1->tv_usec += t2->tv_usec;
	if(t1->tv_usec > 1000000) {
		t1->tv_sec++;
		t1->tv_usec -= 1000000;
	}
}


void timeSub(struct timeval *t1, struct timeval *t2) {
	t1->tv_sec -= t2->tv_sec;
	t1->tv_usec -= t2->tv_usec;
	if(t1->tv_usec < 0) {
		t1->tv_sec--;
		t1->tv_usec += 1000000;
	}
}
void printTestResult() {
	int i = 0;
	for(i = 0; i < TEST_MAX_SIZE; i++) {
		fprintf(stderr, "index:%-2d count:%-8d time:%ldms\n", i, testCount[i], testTime[i].tv_sec*1000+testTime[i].tv_usec/1000);
	}
}


main() {

	unsigned int i, j, k = 1;
	float f = 1.23456f;

	TIME_TEST(0,
		i = 0;
		while(i++ < 0x00ffffff) k +=i/k;
	)

	i = 0;
	TIME_TEST(1,
		while(i++ < 0xff) {
			TIME_TEST(2,
				j = 0;
				while(j++ < 0x0000ffff) k +=i/k;
			)
		}
	)

	TIME_TEST(3,
		i = 0;
		while(i++ < 0x00ffffff) f += 1.0f/i;
	)

	printf("k=%d f=%f\n", k, f);
	printTestResult();
}

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