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Message-ID: <dea1abff6baabfb8a5abc7cf4eb355eb36b0ef8c.camel@redhat.com>
Date: Tue, 11 Oct 2022 13:34:58 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Kuniyuki Iwashima <kuniyu@...zon.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
David Ahern <dsahern@...nel.org>,
Martin KaFai Lau <martin.lau@...nel.org>
Cc: Craig Gallek <kraig@...gle.com>,
Willem de Bruijn <willemb@...gle.com>,
Kuniyuki Iwashima <kuni1840@...il.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 net 3/3] selftest: Add test for SO_INCOMING_CPU.
On Mon, 2022-10-10 at 10:43 -0700, Kuniyuki Iwashima wrote:
> Some highly optimised applications use SO_INCOMING_CPU to make them
> efficient, but they didn't test if it's working correctly by getsockopt()
> to avoid slowing down. As a result, no one noticed it had been broken
> for years, so it's a good time to add a test to catch future regression.
>
> The test does
>
> 1) Create $(nproc) TCP listeners associated with each CPU.
>
> 2) Create 32 child sockets for each listener by calling
> sched_setaffinity() for each CPU.
>
> 3) Check if accept()ed sockets' sk_incoming_cpu matches
> listener's one.
>
> If we see -EAGAIN, SO_INCOMING_CPU is broken. However, we might not see
> any error even if broken; the kernel could miraculously distribute all SYN
> to correct listeners. Not to let that happen, we must increase the number
> of clients and CPUs to some extent, so the test requires $(nproc) >= 2 and
> creates 64 sockets at least.
>
> Test:
> $ nproc
> 96
> $ ./so_incoming_cpu
>
> Before the previous patch:
>
> # Starting 1 tests from 2 test cases.
> # RUN so_incoming_cpu.test1 ...
> # so_incoming_cpu.c:129:test1:Expected cpu (82) == i (0)
> # test1: Test terminated by assertion
> # FAIL so_incoming_cpu.test1
> not ok 1 so_incoming_cpu.test1
> # FAILED: 0 / 1 tests passed.
> # Totals: pass:0 fail:1 xfail:0 xpass:0 skip:0 error:0
>
> After:
>
> # Starting 1 tests from 2 test cases.
> # RUN so_incoming_cpu.test1 ...
> # so_incoming_cpu.c:137:test1:SO_INCOMING_CPU is very likely to be working correctly with 3072 sockets.
> # OK so_incoming_cpu.test1
> ok 1 so_incoming_cpu.test1
> # PASSED: 1 / 1 tests passed.
> # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
> ---
> tools/testing/selftests/net/.gitignore | 1 +
> tools/testing/selftests/net/Makefile | 1 +
> tools/testing/selftests/net/so_incoming_cpu.c | 148 ++++++++++++++++++
> 3 files changed, 150 insertions(+)
> create mode 100644 tools/testing/selftests/net/so_incoming_cpu.c
>
> diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
> index 3d7adee7a3e6..ff8807cc9c2e 100644
> --- a/tools/testing/selftests/net/.gitignore
> +++ b/tools/testing/selftests/net/.gitignore
> @@ -25,6 +25,7 @@ rxtimestamp
> sk_bind_sendto_listen
> sk_connect_zero_addr
> socket
> +so_incoming_cpu
> so_netns_cookie
> so_txtime
> stress_reuseport_listen
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index 2a6b0bc648c4..ba57e7e7dc86 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -70,6 +70,7 @@ TEST_PROGS += io_uring_zerocopy_tx.sh
> TEST_GEN_FILES += bind_bhash
> TEST_GEN_PROGS += sk_bind_sendto_listen
> TEST_GEN_PROGS += sk_connect_zero_addr
> +TEST_GEN_PROGS += so_incoming_cpu
>
> TEST_FILES := settings
>
> diff --git a/tools/testing/selftests/net/so_incoming_cpu.c b/tools/testing/selftests/net/so_incoming_cpu.c
> new file mode 100644
> index 000000000000..0ee0f2e393eb
> --- /dev/null
> +++ b/tools/testing/selftests/net/so_incoming_cpu.c
> @@ -0,0 +1,148 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright Amazon.com Inc. or its affiliates. */
> +#define _GNU_SOURCE
> +#include <sched.h>
> +
> +#include <netinet/in.h>
> +#include <sys/socket.h>
> +#include <sys/sysinfo.h>
> +
> +#include "../kselftest_harness.h"
> +
> +#define CLIENT_PER_SERVER 32 /* More sockets, more reliable */
> +#define NR_SERVER self->nproc
> +#define NR_CLIENT (CLIENT_PER_SERVER * NR_SERVER)
> +
> +FIXTURE(so_incoming_cpu)
> +{
> + int nproc;
> + int *servers;
> + union {
> + struct sockaddr addr;
> + struct sockaddr_in in_addr;
> + };
> + socklen_t addrlen;
> +};
> +
> +FIXTURE_SETUP(so_incoming_cpu)
> +{
> + self->nproc = get_nprocs();
> + ASSERT_LE(2, self->nproc);
> +
> + self->servers = malloc(sizeof(int) * NR_SERVER);
> + ASSERT_NE(self->servers, NULL);
> +
> + self->in_addr.sin_family = AF_INET;
> + self->in_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
> + self->in_addr.sin_port = htons(0);
> + self->addrlen = sizeof(struct sockaddr_in);
> +}
> +
> +FIXTURE_TEARDOWN(so_incoming_cpu)
> +{
> + int i;
> +
> + for (i = 0; i < NR_SERVER; i++)
> + close(self->servers[i]);
> +
> + free(self->servers);
> +}
> +
> +void create_servers(struct __test_metadata *_metadata,
> + FIXTURE_DATA(so_incoming_cpu) *self)
> +{
> + int i, fd, ret;
> +
> + for (i = 0; i < NR_SERVER; i++) {
> + fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
> + ASSERT_NE(fd, -1);
> +
> + ret = setsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &i, sizeof(int));
> + ASSERT_EQ(ret, 0);
> +
> + ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &(int){1}, sizeof(int));
> + ASSERT_EQ(ret, 0);
> +
> + ret = bind(fd, &self->addr, self->addrlen);
> + ASSERT_EQ(ret, 0);
> +
> + if (i == 0) {
> + ret = getsockname(fd, &self->addr, &self->addrlen);
> + ASSERT_EQ(ret, 0);
> + }
> +
> + /* We don't use CLIENT_PER_SERVER here not to block
> + * this test at connect() if SO_INCOMING_CPU is broken.
> + */
> + ret = listen(fd, NR_CLIENT);
> + ASSERT_EQ(ret, 0);
> +
> + self->servers[i] = fd;
> + }
> +}
> +
> +void create_clients(struct __test_metadata *_metadata,
> + FIXTURE_DATA(so_incoming_cpu) *self)
> +{
> + cpu_set_t cpu_set;
> + int i, j, fd, ret;
> +
> + for (i = 0; i < NR_SERVER; i++) {
> + CPU_ZERO(&cpu_set);
> +
> + CPU_SET(i, &cpu_set);
> + ASSERT_EQ(CPU_COUNT(&cpu_set), 1);
> + ASSERT_NE(CPU_ISSET(i, &cpu_set), 0);
> +
> + /* Make sure SYN will be processed on the i-th CPU
> + * and finally distributed to the i-th listener.
> + */
> + sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
> + ASSERT_EQ(ret, 0);
> +
> + for (j = 0; j < CLIENT_PER_SERVER; j++) {
> + fd = socket(AF_INET, SOCK_STREAM, 0);
> + ASSERT_NE(fd, -1);
> +
> + ret = connect(fd, &self->addr, self->addrlen);
> + ASSERT_EQ(ret, 0);
> +
> + close(fd);
> + }
> + }
> +}
> +
> +void verify_incoming_cpu(struct __test_metadata *_metadata,
> + FIXTURE_DATA(so_incoming_cpu) *self)
> +{
> + int i, j, fd, cpu, ret, total = 0;
> + socklen_t len = sizeof(int);
> +
> + for (i = 0; i < NR_SERVER; i++) {
> + for (j = 0; j < CLIENT_PER_SERVER; j++) {
> + /* If we see -EAGAIN here, SO_INCOMING_CPU is broken */
> + fd = accept(self->servers[i], &self->addr, &self->addrlen);
> + ASSERT_NE(fd, -1);
> +
> + ret = getsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &cpu, &len);
> + ASSERT_EQ(ret, 0);
> + ASSERT_EQ(cpu, i);
> +
> + close(fd);
> + total++;
> + }
> + }
> +
> + ASSERT_EQ(total, NR_CLIENT);
> + TH_LOG("SO_INCOMING_CPU is very likely to be "
> + "working correctly with %d sockets.", total);
> +}
> +
> +TEST_F(so_incoming_cpu, test1)
> +{
> + create_servers(_metadata, self);
> + create_clients(_metadata, self);
> + verify_incoming_cpu(_metadata, self);
> +}
I think it would be nicer if you could add more test-cases, covering
e.g.:
- set SO_INCOMING_CPU after SO_REUSE_PORT,
- initially including a socket without SO_INCOMING_CPU and the removing
it from the soreuseport set
Thanks,
Paolo
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