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A simple benchmark test for DNS lookups with libc getaddrinfo() function
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#define NUM_LOOKUPS 1024
#define MAX_RATE 10
#define DOMAIN ""
int main() {
const char *hostname = DOMAIN;
struct addrinfo hints;
int err;
struct timespec start_time;
struct timespec end_time;
double latency, total;
int i, success;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = 0;
fprintf(stderr, "Running benchmark\n");
success = 0;
for (i = 0; i < NUM_LOOKUPS; i++) {
struct addrinfo *res;
clock_gettime(CLOCK_REALTIME, &start_time);
err = getaddrinfo (hostname, NULL, NULL, &res);
if (err) {
fprintf(stderr, "getaddrinfo error: %s\n", gai_strerror(err));
} else {
clock_gettime(CLOCK_REALTIME, &end_time);
latency = (double)end_time.tv_sec + (double)end_time.tv_nsec / 1e9;
latency -= (double)start_time.tv_sec + (double)start_time.tv_nsec / 1e9;
total += latency;
double avg = total / (double)success * 1000.0;
printf("getaddrinfo: %d/%d successful lookups\n", success, NUM_LOOKUPS);
printf("getaddrinfo: %lfms average per lookup\n", avg);
return 0;
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