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Message-ID: <CAJnrk1Zn2sy=bVC5HBggRHTTkjqqXZAx1VyO1r8PWSkLBY7KRw@mail.gmail.com>
Date: Mon, 9 May 2022 18:01:23 -0700
From: Joanne Koong <joannelkoong@...il.com>
To: netdev <netdev@...r.kernel.org>
Cc: Eric Dumazet <edumazet@...gle.com>,
Martin KaFai Lau <kafai@...com>,
Jakub Kicinski <kuba@...nel.org>,
David Miller <davem@...emloft.net>
Subject: Re: [PATCH net-next v2 2/2] selftests: Add test for timing a bind
request to a port with a populated bhash entry
On Mon, May 9, 2022 at 5:54 PM Joanne Koong <joannelkoong@...il.com> wrote:
>
> 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 test locally, I did:
> * ulimit -n 65535000
> * ip addr add 2001:0db8:0:f101::1 dev eth0
> * ./bind_bhash_test 443
>
> Signed-off-by: Joanne Koong <joannelkoong@...il.com>
> ---
> tools/testing/selftests/net/.gitignore | 1 +
> tools/testing/selftests/net/Makefile | 2 +
> tools/testing/selftests/net/bind_bhash_test.c | 119 ++++++++++++++++++
> 3 files changed, 122 insertions(+)
> create mode 100644 tools/testing/selftests/net/bind_bhash_test.c
>
> diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
> index 21a411b04890..735423136bc4 100644
> --- a/tools/testing/selftests/net/.gitignore
> +++ b/tools/testing/selftests/net/.gitignore
> @@ -36,3 +36,4 @@ gro
> ioam6_parser
> toeplitz
> cmsg_sender
> +bind_bhash_test
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index af7f6e6ff182..b2cf3fa152ad 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -55,6 +55,7 @@ TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa
> TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls
> TEST_GEN_FILES += toeplitz
> TEST_GEN_FILES += cmsg_sender
> +TEST_GEN_FILES += bind_bhash_test
>
> TEST_FILES := settings
>
> @@ -63,4 +64,5 @@ include ../lib.mk
>
> $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma
> $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread
> +$(OUTPUT)/bind_bhash_test: LDLIBS += -lpthread
> $(OUTPUT)/tcp_inq: LDLIBS += -lpthread
> diff --git a/tools/testing/selftests/net/bind_bhash_test.c b/tools/testing/selftests/net/bind_bhash_test.c
> new file mode 100644
> index 000000000000..252e73754e76
> --- /dev/null
> +++ b/tools/testing/selftests/net/bind_bhash_test.c
> @@ -0,0 +1,119 @@
> +// 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>
> +
> +#define MAX_THREADS 600
> +#define MAX_CONNECTIONS 40
> +
> +static const char *bind_addr = "::1";
> +static const char *port;
> +
> +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;
> +
> + sock_fd = socket(AF_INET6, SOCK_STREAM, 0);
> + if (sock_fd < 0) {
> + perror("socket fd err");
> + return -1;
> + }
> +
> + hint.ai_family = AF_INET6;
> + hint.ai_socktype = SOCK_STREAM;
> +
> + err = getaddrinfo(addr, port, &hint, &res);
> + if (err) {
> + perror("getaddrinfo failed");
> + return -1;
> + }
> +
> + if (opt) {
> + err = setsockopt(sock_fd, SOL_SOCKET, opt, &reuse, sizeof(reuse));
> + if (err) {
> + perror("setsockopt failed");
> + return -1;
> + }
> + }
> +
> + err = bind(sock_fd, res->ai_addr, res->ai_addrlen);
> + if (err) {
> + perror("failed to bind to port");
> + return -1;
> + }
> +
> + return sock_fd;
> +}
> +
> +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, bind_addr);
> + if (sock_fd < 0)
> + return NULL;
> + 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 != 2) {
> + printf("Usage: listener <port>\n");
> + return -1;
> + }
> +
> + port = argv[1];
> +
> + listener_fd = bind_socket(SO_REUSEADDR | SO_REUSEPORT, bind_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);
> +
> + begin = clock();
> +
> + /* Bind to the same port on a different address */
> + sock_fd = bind_socket(0, "2001:0db8:0:f101::1");
> +
> + end = clock();
> +
> + printf("time spent = %f\n", (double)(end - begin) / CLOCKS_PER_SEC);
> +
> + /* clean up */
> + close(sock_fd);
> + close(listener_fd);
> + for (i = 0; i < MAX_THREADS; i++) {
> + for (j = 0; i < MAX_THREADS; i++)
> + close(fd_array[i][j]);
> + }
> +
> + return 0;
> +}
Eric, this is what I used locally to test the bind request. Depending
on what you think about this bhash2 proposal, I am happy to clean up
this test in a v3 follow-up.
> --
> 2.30.2
>
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