linux/tools/testing/selftests/net/bind_bhash.c
Joanne Koong c35ecb95c4 selftests/net: Add test for timing a bind request to a port with a populated bhash entry
This test populates the bhash table for a given port with
MAX_THREADS * MAX_CONNECTIONS sockets, and then times how long
a bind request on the port takes.

When populating the bhash table, we create the sockets and then bind
the sockets to the same address and port (SO_REUSEADDR and SO_REUSEPORT
are set). When timing how long a bind on the port takes, we bind on a
different address without SO_REUSEPORT set. We do not set SO_REUSEPORT
because we are interested in the case where the bind request does not
go through the tb->fastreuseport path, which is fragile (eg
tb->fastreuseport path does not work if binding with a different uid).

To run the script:
    Usage: ./bind_bhash.sh [-6 | -4] [-p port] [-a address]
	    6: use ipv6
	    4: use ipv4
	    port: Port number
	    address: ip address

Without any arguments, ./bind_bhash.sh defaults to ipv6 using ip address
"2001:0db8:0:f101::1" on port 443.

On my local machine, I see:
ipv4:
before - 0.002317 seconds
with bhash2 - 0.000020 seconds

ipv6:
before - 0.002431 seconds
with bhash2 - 0.000021 seconds

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-24 19:30:09 -07:00

145 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* This times how long it takes to bind to a port when the port already
* has multiple sockets in its bhash table.
*
* In the setup(), we populate the port's bhash table with
* MAX_THREADS * MAX_CONNECTIONS number of entries.
*/
#include <unistd.h>
#include <stdio.h>
#include <netdb.h>
#include <pthread.h>
#include <string.h>
#include <stdbool.h>
#define MAX_THREADS 600
#define MAX_CONNECTIONS 40
static const char *setup_addr_v6 = "::1";
static const char *setup_addr_v4 = "127.0.0.1";
static const char *setup_addr;
static const char *bind_addr;
static const char *port;
bool use_v6;
int ret;
static int fd_array[MAX_THREADS][MAX_CONNECTIONS];
static int bind_socket(int opt, const char *addr)
{
struct addrinfo *res, hint = {};
int sock_fd, reuse = 1, err;
int domain = use_v6 ? AF_INET6 : AF_INET;
sock_fd = socket(domain, SOCK_STREAM, 0);
if (sock_fd < 0) {
perror("socket fd err");
return sock_fd;
}
hint.ai_family = domain;
hint.ai_socktype = SOCK_STREAM;
err = getaddrinfo(addr, port, &hint, &res);
if (err) {
perror("getaddrinfo failed");
goto cleanup;
}
if (opt) {
err = setsockopt(sock_fd, SOL_SOCKET, opt, &reuse, sizeof(reuse));
if (err) {
perror("setsockopt failed");
goto cleanup;
}
}
err = bind(sock_fd, res->ai_addr, res->ai_addrlen);
if (err) {
perror("failed to bind to port");
goto cleanup;
}
return sock_fd;
cleanup:
close(sock_fd);
return err;
}
static void *setup(void *arg)
{
int sock_fd, i;
int *array = (int *)arg;
for (i = 0; i < MAX_CONNECTIONS; i++) {
sock_fd = bind_socket(SO_REUSEADDR | SO_REUSEPORT, setup_addr);
if (sock_fd < 0) {
ret = sock_fd;
pthread_exit(&ret);
}
array[i] = sock_fd;
}
return NULL;
}
int main(int argc, const char *argv[])
{
int listener_fd, sock_fd, i, j;
pthread_t tid[MAX_THREADS];
clock_t begin, end;
if (argc != 4) {
printf("Usage: listener <port> <ipv6 | ipv4> <bind-addr>\n");
return -1;
}
port = argv[1];
use_v6 = strcmp(argv[2], "ipv6") == 0;
bind_addr = argv[3];
setup_addr = use_v6 ? setup_addr_v6 : setup_addr_v4;
listener_fd = bind_socket(SO_REUSEADDR | SO_REUSEPORT, setup_addr);
if (listen(listener_fd, 100) < 0) {
perror("listen failed");
return -1;
}
/* Set up threads to populate the bhash table entry for the port */
for (i = 0; i < MAX_THREADS; i++)
pthread_create(&tid[i], NULL, setup, fd_array[i]);
for (i = 0; i < MAX_THREADS; i++)
pthread_join(tid[i], NULL);
if (ret)
goto done;
begin = clock();
/* Bind to the same port on a different address */
sock_fd = bind_socket(0, bind_addr);
if (sock_fd < 0)
goto done;
end = clock();
printf("time spent = %f\n", (double)(end - begin) / CLOCKS_PER_SEC);
/* clean up */
close(sock_fd);
done:
close(listener_fd);
for (i = 0; i < MAX_THREADS; i++) {
for (j = 0; i < MAX_THREADS; i++)
close(fd_array[i][j]);
}
return 0;
}