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- /* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
- /* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
- #include <stdlib.h>
- #include <stdio.h>
- #include <sys/time.h>
- #include <math.h>
- #include <pthread.h>
- #define OVERHEAD_TIMES 30000
- double my_sqrt(double num)
- {
- return sqrt(num);
- }
- pthread_t my_pthread_self(void)
- {
- return pthread_self();
- }
- int main (int argc, char ** argv, char ** envp)
- {
- struct timeval tv;
- gettimeofday(&tv, NULL);
- if (argc < 2)
- return -1;
- unsigned long long msec1 = atoll(argv[1]);
- unsigned long long msec2 = tv.tv_sec * 1000000ULL + tv.tv_usec;
- struct timeval tv1, tv2;
- gettimeofday(&tv1, NULL);
- for (int j = 0 ; j < OVERHEAD_TIMES ; j++)
- gettimeofday(&tv, NULL);
- gettimeofday(&tv2, NULL);
- unsigned long long msec3 = tv1.tv_sec * 1000000ULL + tv1.tv_usec;
- unsigned long long msec4 = tv2.tv_sec * 1000000ULL + tv2.tv_usec;
- unsigned long long overhead = (msec4 - msec3) / OVERHEAD_TIMES;
- printf("%llu\n", msec2 - msec1 - overhead);
- my_sqrt(1.0);
- my_sqrt(2.0);
- my_pthread_self();
- return 0;
- }
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