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Bug #19461 » localtime_test.c

nobu (Nobuyoshi Nakada), 02/24/2023 02:51 PM

 
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sys/wait.h>

static void sir_local_alot(unsigned long count, int r)
{
uint64_t start = clock_gettime_nsec_np(CLOCK_MONOTONIC);
time_t t = time(NULL);
const char *s = "";
if (r) {
s = "_r";
for (unsigned long i = 0; i < count; ++i) {
struct tm tm;
localtime_r(&t, &tm);
}
}
else {
for (unsigned long i = 0; i < count; ++i) {
localtime(&t);
}
}
uint64_t n = clock_gettime_nsec_np(CLOCK_MONOTONIC) - start;
printf(" localtime%-2s = %lld.%09u\n", s, n / 1000000000ULL, (unsigned int)(n % 1000000000ULL));
}

int main(int argc, char **argv)
{
#define COUNT 10000
unsigned long count = COUNT;
if ((argc > 1) && !(count = strtoul(argv[1], NULL, 0))) {
fprintf(stderr, "invalid count: %s\n", argv[1]);
return EXIT_FAILURE;
}

printf("Measuring in parent\n");
sir_local_alot(count, 1);
sir_local_alot(count, 0);

printf("Measuring in child\n");
pid_t pid = fork();
if (!pid) {
sir_local_alot(count, 1);
sir_local_alot(count, 0);
}
wait(&pid);
return EXIT_SUCCESS;
}
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