diff mbox series

[net-next,v2,2/3] selftests/net: Add test for timing a bind request to a port with a populated bhash entry

Message ID 20220712235310.1935121-3-joannelkoong@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Add a second bind table hashed by port + address | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 2 maintainers not CCed: linux-kselftest@vger.kernel.org shuah@kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success net selftest script(s) already in Makefile
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 82 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Joanne Koong July 12, 2022, 11:53 p.m. UTC 
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).

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>
---
 tools/testing/selftests/net/.gitignore    |   3 +-
 tools/testing/selftests/net/Makefile      |   3 +
 tools/testing/selftests/net/bind_bhash.c  | 119 ++++++++++++++++++++++
 tools/testing/selftests/net/bind_bhash.sh |  23 +++++
 4 files changed, 147 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/net/bind_bhash.c
 create mode 100755 tools/testing/selftests/net/bind_bhash.sh

Comments

Paolo Abeni July 14, 2022, 9:18 a.m. UTC | #1 
On Tue, 2022-07-12 at 16:53 -0700, Joanne Koong 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).
> 
> 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>
> ---
>  tools/testing/selftests/net/.gitignore    |   3 +-
>  tools/testing/selftests/net/Makefile      |   3 +
>  tools/testing/selftests/net/bind_bhash.c  | 119 ++++++++++++++++++++++
>  tools/testing/selftests/net/bind_bhash.sh |  23 +++++
>  4 files changed, 147 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/net/bind_bhash.c
>  create mode 100755 tools/testing/selftests/net/bind_bhash.sh
> 
> diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
> index 1257baa79286..5b1adf6e29ae 100644
> --- a/tools/testing/selftests/net/.gitignore
> +++ b/tools/testing/selftests/net/.gitignore
> @@ -37,4 +37,5 @@ gro
>  ioam6_parser
>  toeplitz
>  cmsg_sender
> -unix_connect
> \ No newline at end of file
> +unix_connect
> +bind_bhash
> diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> index ddad703ace34..e678fc3030a2 100644
> --- a/tools/testing/selftests/net/Makefile
> +++ b/tools/testing/selftests/net/Makefile
> @@ -39,6 +39,7 @@ TEST_PROGS += vrf_strict_mode_test.sh
>  TEST_PROGS += arp_ndisc_evict_nocarrier.sh
>  TEST_PROGS += ndisc_unsolicited_na_test.sh
>  TEST_PROGS += stress_reuseport_listen.sh
> +TEST_PROGS += bind_bhash.sh
>  TEST_PROGS_EXTENDED := in_netns.sh setup_loopback.sh setup_veth.sh
>  TEST_PROGS_EXTENDED += toeplitz_client.sh toeplitz.sh
>  TEST_GEN_FILES =  socket nettest
> @@ -59,6 +60,7 @@ TEST_GEN_FILES += toeplitz
>  TEST_GEN_FILES += cmsg_sender
>  TEST_GEN_FILES += stress_reuseport_listen
>  TEST_PROGS += test_vxlan_vnifiltering.sh
> +TEST_GEN_FILES += bind_bhash
>  
>  TEST_FILES := settings
>  
> @@ -70,3 +72,4 @@ include bpf/Makefile
>  $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma
>  $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread
>  $(OUTPUT)/tcp_inq: LDLIBS += -lpthread
> +$(OUTPUT)/bind_bhash: LDLIBS += -lpthread
> diff --git a/tools/testing/selftests/net/bind_bhash.c b/tools/testing/selftests/net/bind_bhash.c
> new file mode 100644
> index 000000000000..252e73754e76
> --- /dev/null
> +++ b/tools/testing/selftests/net/bind_bhash.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");

I think it's better/nicer if you make this address configurable from
the command line, instead of hard-codying it here.
> +
> +	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;
> +}
> diff --git a/tools/testing/selftests/net/bind_bhash.sh b/tools/testing/selftests/net/bind_bhash.sh
> new file mode 100755
> index 000000000000..f7794d63efd2
> --- /dev/null
> +++ b/tools/testing/selftests/net/bind_bhash.sh
> @@ -0,0 +1,23 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +
> +NR_FILES=32768
> +SAVED_NR_FILES=$(ulimit -n)
> +
> +setup() {
> +	ip addr add dev eth0 2001:0db8:0:f101::1

If you add the 'nodad' option here...

> +	ulimit -n $NR_FILES
> +	sleep 1

... this should not be needed

Also what about ipv4 tests?


Thanks!

Paolo
Joanne Koong July 15, 2022, 6:22 p.m. UTC | #2 
On Thu, Jul 14, 2022 at 2:18 AM Paolo Abeni <pabeni@redhat.com> wrote:
>
> On Tue, 2022-07-12 at 16:53 -0700, Joanne Koong 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).
> >
> > 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>
> > ---
> >  tools/testing/selftests/net/.gitignore    |   3 +-
> >  tools/testing/selftests/net/Makefile      |   3 +
> >  tools/testing/selftests/net/bind_bhash.c  | 119 ++++++++++++++++++++++
> >  tools/testing/selftests/net/bind_bhash.sh |  23 +++++
> >  4 files changed, 147 insertions(+), 1 deletion(-)
> >  create mode 100644 tools/testing/selftests/net/bind_bhash.c
> >  create mode 100755 tools/testing/selftests/net/bind_bhash.sh
> >
> > diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
> > index 1257baa79286..5b1adf6e29ae 100644
> > --- a/tools/testing/selftests/net/.gitignore
> > +++ b/tools/testing/selftests/net/.gitignore
> > @@ -37,4 +37,5 @@ gro
> >  ioam6_parser
> >  toeplitz
> >  cmsg_sender
> > -unix_connect
> > \ No newline at end of file
> > +unix_connect
> > +bind_bhash
> > diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> > index ddad703ace34..e678fc3030a2 100644
> > --- a/tools/testing/selftests/net/Makefile
> > +++ b/tools/testing/selftests/net/Makefile
> > @@ -39,6 +39,7 @@ TEST_PROGS += vrf_strict_mode_test.sh
> >  TEST_PROGS += arp_ndisc_evict_nocarrier.sh
> >  TEST_PROGS += ndisc_unsolicited_na_test.sh
> >  TEST_PROGS += stress_reuseport_listen.sh
> > +TEST_PROGS += bind_bhash.sh
> >  TEST_PROGS_EXTENDED := in_netns.sh setup_loopback.sh setup_veth.sh
> >  TEST_PROGS_EXTENDED += toeplitz_client.sh toeplitz.sh
> >  TEST_GEN_FILES =  socket nettest
> > @@ -59,6 +60,7 @@ TEST_GEN_FILES += toeplitz
> >  TEST_GEN_FILES += cmsg_sender
> >  TEST_GEN_FILES += stress_reuseport_listen
> >  TEST_PROGS += test_vxlan_vnifiltering.sh
> > +TEST_GEN_FILES += bind_bhash
> >
> >  TEST_FILES := settings
> >
> > @@ -70,3 +72,4 @@ include bpf/Makefile
> >  $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma
> >  $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread
> >  $(OUTPUT)/tcp_inq: LDLIBS += -lpthread
> > +$(OUTPUT)/bind_bhash: LDLIBS += -lpthread
> > diff --git a/tools/testing/selftests/net/bind_bhash.c b/tools/testing/selftests/net/bind_bhash.c
> > new file mode 100644
> > index 000000000000..252e73754e76
> > --- /dev/null
> > +++ b/tools/testing/selftests/net/bind_bhash.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");
>
> I think it's better/nicer if you make this address configurable from
> the command line, instead of hard-codying it here.
I will make this change for v3.
> > +
> > +     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;
> > +}
> > diff --git a/tools/testing/selftests/net/bind_bhash.sh b/tools/testing/selftests/net/bind_bhash.sh
> > new file mode 100755
> > index 000000000000..f7794d63efd2
> > --- /dev/null
> > +++ b/tools/testing/selftests/net/bind_bhash.sh
> > @@ -0,0 +1,23 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +NR_FILES=32768
> > +SAVED_NR_FILES=$(ulimit -n)
> > +
> > +setup() {
> > +     ip addr add dev eth0 2001:0db8:0:f101::1
>
> If you add the 'nodad' option here...
>
> > +     ulimit -n $NR_FILES
> > +     sleep 1
>
> ... this should not be needed
Awesome! Thanks, I will add this 'nodad' option.
>
> Also what about ipv4 tests?
I will update this to also include the ipv4 version of the test in v3.
>
>
> Thanks!
>
> Paolo
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
index 1257baa79286..5b1adf6e29ae 100644
--- a/tools/testing/selftests/net/.gitignore
+++ b/tools/testing/selftests/net/.gitignore
@@ -37,4 +37,5 @@  gro
 ioam6_parser
 toeplitz
 cmsg_sender
-unix_connect
\ No newline at end of file
+unix_connect
+bind_bhash
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index ddad703ace34..e678fc3030a2 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -39,6 +39,7 @@  TEST_PROGS += vrf_strict_mode_test.sh
 TEST_PROGS += arp_ndisc_evict_nocarrier.sh
 TEST_PROGS += ndisc_unsolicited_na_test.sh
 TEST_PROGS += stress_reuseport_listen.sh
+TEST_PROGS += bind_bhash.sh
 TEST_PROGS_EXTENDED := in_netns.sh setup_loopback.sh setup_veth.sh
 TEST_PROGS_EXTENDED += toeplitz_client.sh toeplitz.sh
 TEST_GEN_FILES =  socket nettest
@@ -59,6 +60,7 @@  TEST_GEN_FILES += toeplitz
 TEST_GEN_FILES += cmsg_sender
 TEST_GEN_FILES += stress_reuseport_listen
 TEST_PROGS += test_vxlan_vnifiltering.sh
+TEST_GEN_FILES += bind_bhash
 
 TEST_FILES := settings
 
@@ -70,3 +72,4 @@  include bpf/Makefile
 $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma
 $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread
 $(OUTPUT)/tcp_inq: LDLIBS += -lpthread
+$(OUTPUT)/bind_bhash: LDLIBS += -lpthread
diff --git a/tools/testing/selftests/net/bind_bhash.c b/tools/testing/selftests/net/bind_bhash.c
new file mode 100644
index 000000000000..252e73754e76
--- /dev/null
+++ b/tools/testing/selftests/net/bind_bhash.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;
+}
diff --git a/tools/testing/selftests/net/bind_bhash.sh b/tools/testing/selftests/net/bind_bhash.sh
new file mode 100755
index 000000000000..f7794d63efd2
--- /dev/null
+++ b/tools/testing/selftests/net/bind_bhash.sh
@@ -0,0 +1,23 @@ 
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+NR_FILES=32768
+SAVED_NR_FILES=$(ulimit -n)
+
+setup() {
+	ip addr add dev eth0 2001:0db8:0:f101::1
+	ulimit -n $NR_FILES
+	sleep 1
+}
+
+cleanup() {
+	ip addr del 2001:0db8:0:f101::1 dev eth0
+	ulimit -n $SAVED_NR_FILES
+}
+
+trap cleanup EXIT
+
+setup
+./bind_bhash 443
+
+exit $EXIT_STATUS