local_lat.cpp

#include "../include/zmq.h"
#include <stdio.h>
#include <stdlib.h>

int main (int argc, char *argv[])
{
    const char *bind_to;
    int roundtrip_count;
    size_t message_size;
    void *ctx;
    void *s;
    int rc;
    int i;
    zmq_msg_t msg;

    if (argc != 4) {
        printf ("usage: local_lat <bind-to> <message-size> "
                "<roundtrip-count>\n");
        return 1;
    }
    bind_to = argv[1];
    message_size = atoi (argv[2]);
    roundtrip_count = atoi (argv[3]);

    ctx = zmq_init (1);
    if (!ctx) {
        printf ("error in zmq_init: %s\n", zmq_strerror (errno));
        return -1;
    }

    s = zmq_socket (ctx, ZMQ_REP);
    if (!s) {
        printf ("error in zmq_socket: %s\n", zmq_strerror (errno));
        return -1;
    }

    rc = zmq_bind (s, bind_to);
    if (rc != 0) {
        printf ("error in zmq_bind: %s\n", zmq_strerror (errno));
        return -1;
    }

    rc = zmq_msg_init (&msg);
    if (rc != 0) {
        printf ("error in zmq_msg_init: %s\n", zmq_strerror (errno));
        return -1;
    }

    for (i = 0; i != roundtrip_count + 1; i++) {
        rc = zmq_recvmsg (s, &msg, 0);
        if (rc < 0) {
            printf ("error in zmq_recvmsg: %s\n", zmq_strerror (errno));
            return -1;
        }
        if (zmq_msg_size (&msg) != message_size) {
            printf ("message of incorrect size received\n");
            return -1;
        }
        rc = zmq_sendmsg (s, &msg, 0);
        if (rc < 0) {
            printf ("error in zmq_sendmsg: %s\n", zmq_strerror (errno));
            return -1;
        }
    }

    rc = zmq_msg_close (&msg);
    if (rc != 0) {
        printf ("error in zmq_msg_close: %s\n", zmq_strerror (errno));
        return -1;
    }

    zmq_sleep (1);

    rc = zmq_close (s);
    if (rc != 0) {
        printf ("error in zmq_close: %s\n", zmq_strerror (errno));
        return -1;
    }

    rc = zmq_ctx_term (ctx);
    if (rc != 0) {
        printf ("error in zmq_ctx_term: %s\n", zmq_strerror (errno));
        return -1;
    }

    return 0;
}

remote_lat.cpp

#include "../include/zmq.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main (int argc, char *argv[])
{
    const char *connect_to;
    int roundtrip_count;
    size_t message_size;
    void *ctx;
    void *s;
    int rc;
    int i;
    zmq_msg_t msg;
    void *watch;
    unsigned long elapsed;
    double latency;

    if (argc != 4) {
        printf ("usage: remote_lat <connect-to> <message-size> "
                "<roundtrip-count>\n");
        return 1;
    }
    connect_to = argv[1];
    message_size = atoi (argv[2]);
    roundtrip_count = atoi (argv[3]);

    ctx = zmq_init (1);
    if (!ctx) {
        printf ("error in zmq_init: %s\n", zmq_strerror (errno));
        return -1;
    }

    s = zmq_socket (ctx, ZMQ_REQ);
    if (!s) {
        printf ("error in zmq_socket: %s\n", zmq_strerror (errno));
        return -1;
    }

    rc = zmq_connect (s, connect_to);
    if (rc != 0) {
        printf ("error in zmq_connect: %s\n", zmq_strerror (errno));
        return -1;
    }

    rc = zmq_msg_init_size (&msg, message_size);
    if (rc != 0) {
        printf ("error in zmq_msg_init_size: %s\n", zmq_strerror (errno));
        return -1;
    }
    memset (zmq_msg_data (&msg), 0, message_size);
    rc = zmq_sendmsg (s, &msg, 0);
    if (rc < 0) {
        printf ("error in zmq_sendmsg: %s\n", zmq_strerror (errno));
        return -1;
    }
    rc = zmq_recvmsg (s, &msg, 0);
    if (rc < 0) {
        printf ("error in zmq_recvmsg: %s\n", zmq_strerror (errno));
        return -1;
    }
    if (zmq_msg_size (&msg) != message_size) {
        printf ("message of incorrect size received\n");
        return -1;
    }

    watch = zmq_stopwatch_start ();

    for (i = 0; i != roundtrip_count; i++) {
        rc = zmq_sendmsg (s, &msg, 0);
        if (rc < 0) {
            printf ("error in zmq_sendmsg: %s\n", zmq_strerror (errno));
            return -1;
        }
        rc = zmq_recvmsg (s, &msg, 0);
        if (rc < 0) {
            printf ("error in zmq_recvmsg: %s\n", zmq_strerror (errno));
            return -1;
        }
        if (zmq_msg_size (&msg) != message_size) {
            printf ("message of incorrect size received\n");
            return -1;
        }
    }

    elapsed = zmq_stopwatch_stop (watch);

    rc = zmq_msg_close (&msg);
    if (rc != 0) {
        printf ("error in zmq_msg_close: %s\n", zmq_strerror (errno));
        return -1;
    }

    latency = (double) elapsed / (roundtrip_count * 2);

    printf ("message size: %d [B]\n", (int) message_size);
    printf ("roundtrip count: %d\n", (int) roundtrip_count);
    printf ("average latency: %.3f [us]\n", (double) latency);

    rc = zmq_close (s);
    if (rc != 0) {
        printf ("error in zmq_close: %s\n", zmq_strerror (errno));
        return -1;
    }

    rc = zmq_ctx_term (ctx);
    if (rc != 0) {
        printf ("error in zmq_ctx_term: %s\n", zmq_strerror (errno));
        return -1;
    }

    return 0;
}

40us is for send & receive, so the latency for one side is around 20us.

Am nowhere near getting that figures. Can you please check my sender and reciever code please and check from your end. It will be a great help

Anything I can try to reduce latency?