udp sendto micro benchmark

udp_send_bm.c

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <strings.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>

struct timespec diff(struct timespec start, struct timespec end)
{
    struct timespec temp;

    if ((end.tv_nsec - start.tv_nsec) < 0)
    {
        temp.tv_sec = end.tv_sec - start.tv_sec - 1;
        temp.tv_nsec = 1000000000 + end.tv_nsec - start.tv_nsec;
    }
    else
    {
        temp.tv_sec = end.tv_sec - start.tv_sec;
        temp.tv_nsec = end.tv_nsec - start.tv_nsec;
    }
    return temp;
}

int main(int argc, char** argv)
{
    struct sockaddr_in serv_addr;
    int fd, slen = sizeof(serv_addr);
    char buf[2048];
    //char buf[2048] = { [0 ... 2046] = 'A', [2047] = '\0' };

    if (argc != 3)
    {
        fprintf(stderr, "usage: udp_send_bm <ip> <port>\n");
        exit(1);
    }

    fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    fcntl(fd, F_SETFL, O_NONBLOCK);

    bzero(&serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(atoi(argv[2]));
    inet_aton(argv[1], &serv_addr.sin_addr);

    struct timespec  ts1, ts2;
    const int packet_count = 1000000;

    printf("Loop iteration count: %d\n", packet_count);

    for (int i = 0; i < 10; i++)
    {
        int packet_size = 100 * (1 + i);

        clock_gettime(CLOCK_MONOTONIC_RAW, &ts1);

        for (int j = 0; j < packet_count; j++)
            sendto(fd, buf, packet_size, 0, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

        clock_gettime(CLOCK_MONOTONIC_RAW, &ts2);

        struct timespec res = diff(ts1, ts2);
        unsigned long it_time = (res.tv_sec * 1000000000L) + res.tv_nsec;
        double tt = (double) (ts2.tv_nsec - ts1.tv_nsec) / 1000000000L + (double) (ts2.tv_sec - ts1.tv_sec);

        printf("Packet Size %d // Time per sendto() %lu nanosec // Total time %f\n",
               packet_size, it_time / packet_count, tt);
    }

    close(fd);

    return 0;
}