Tarantool-c slow

server.c

//plain http server based on rosseta
//expected clients are http browser
//tested with wrk resulted to 30,000 rps
//wrk http://127.0.0.1:8080 -c 15 -t 3 -d 5

//compile with
//gcc server.c -o server

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <err.h>
#include <string.h>



int main()
{
    const char *msg = "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: 13\r\nConnection: close\r\n\r\nHello, world!";
    int ret = strlen(msg);
    int one = 1, client_fd;
    struct sockaddr_in svr_addr, cli_addr;
    socklen_t sin_len = sizeof(cli_addr);

    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0)
        err(1, "can't open socket");

    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(int));

    int port = 8080;
    svr_addr.sin_family = AF_INET;
    svr_addr.sin_addr.s_addr = INADDR_ANY;
    svr_addr.sin_port = htons(port);

    if (bind(sock, (struct sockaddr *) &svr_addr, sizeof(svr_addr)) == -1) {
        close(sock);
        err(1, "Can't bind");
    }

    listen(sock, 5);
    while (1) {
        client_fd = accept(sock, (struct sockaddr *) &cli_addr, &sin_len);
        //printf("got connection\n");

        if (client_fd == -1) {
        perror("Can't accept");
        continue;
        }

        send(client_fd, msg, ret,MSG_NOSIGNAL); /*-1:'\0'*/
        //write(client_fd, msg, ret);
        close(client_fd);
    }
}

server_tar.c

//http server connected to tarantool expecting a reply 
//expected clients are http browser
//tested with wrk resulted to 900 rps
//wrk http://127.0.0.1:8080 -c 15 -t 3 -d 5

//compile with
//$tarantool-c is the tarantool-c root
//gcc server_tar.c -I$tarantool-c/include -L$tarantool-c/lib -ltarantool -o server_tar

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <err.h>
#include <string.h>

#include <tarantool/tarantool.h>
#include <tarantool/tnt_net.h>
#include <tarantool/tnt_opt.h>


struct tnt_stream *tnt;
struct tnt_stream *tuple;
struct tnt_reply reply;

int main()
{
    const char *msg = "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: 13\r\nConnection: close\r\n\r\nHello, world!";
    int ret = strlen(msg);
    int one = 1, client_fd;
    struct sockaddr_in svr_addr, cli_addr;
    socklen_t sin_len = sizeof(cli_addr);

    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0)
        err(1, "can't open socket");

    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(int));

    int port = 8080;
    svr_addr.sin_family = AF_INET;
    svr_addr.sin_addr.s_addr = INADDR_ANY;
    svr_addr.sin_port = htons(port);

    if (bind(sock, (struct sockaddr *) &svr_addr, sizeof(svr_addr)) == -1) {
        close(sock);
        err(1, "Can't bind");
    }

    listen(sock, 5);

    //initialize tarantool
    const char * uri = "127.0.0.101:3301";
    tnt = tnt_net(NULL); // Allocating stream
	tnt_set(tnt, TNT_OPT_URI, uri); // Setting URI

	tnt_connect(tnt);
	tuple = tnt_object(NULL);
	tnt_reply_init(&reply);


    //server event loop
    while (1) {
        client_fd = accept(sock, (struct sockaddr *) &cli_addr, &sin_len);
        //printf("got connection\n");

        if (client_fd == -1) {
            perror("Can't accept");
            continue;
        }

        //tarantool details
        tnt_object_add_array(tuple, 1); //might be the number of rows involved
        tnt_object_add_int(tuple, 8); //which row it belongs to

        tnt_select(tnt, 10, 0, UINT32_MAX, 0, 0, tuple); //10 is the space id

        tnt_flush(tnt); 
        tnt_object_reset(tuple);

        int r = tnt->read_reply(tnt, &reply);
        while(1){
            if (r == 1)
            {
                // This means that we're reading responses way to fast and there is nothing in the socket
                // Let's just wait a little bit
                // It is better to wait 1 ms one in a while than to use mutex every time in terms of CPU  usage
                usleep(1000);
            }
            else if (r == -1)
            {
                printf("Read reply failed %s\n", reply.error);

            }else{
                //reply suceeds, do something
                break;
            }
        }
        tnt_reply_free(&reply);

        send(client_fd, msg, ret,MSG_NOSIGNAL);

        close(client_fd);
    }
    
    //close tnt connection if the server terminates nicely
    tnt_close(tnt); tnt_stream_free(tnt);
}