[PATCH net-next] selftests: devmem: configure HDS threshold

[PATCH net-next] selftests: devmem: configure HDS threshold

[Taehee Yoo]

The devmem TCP requires the hds-thresh value to be 0, but it doesn't
change it automatically.
Therefore, configure_hds_thresh() is added to handle this.

The run_devmem_tests() now tests hds_thresh, but it skips test if the
hds_thresh_max value is 0.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---
 .../selftests/drivers/net/hw/ncdevmem.c       | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
index cc9b40d9c5d5..d78b5e5697d7 100644
--- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
+++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
@@ -349,6 +349,72 @@ static int configure_headersplit(bool on)
 	return ret;
 }
 
+static int configure_hds_thresh(int len)
+{
+	struct ethtool_rings_get_req *get_req;
+	struct ethtool_rings_get_rsp *get_rsp;
+	struct ethtool_rings_set_req *req;
+	struct ynl_error yerr;
+	struct ynl_sock *ys;
+	int ret;
+
+	ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
+	if (!ys) {
+		fprintf(stderr, "YNL: %s\n", yerr.msg);
+		return -1;
+	}
+
+	req = ethtool_rings_set_req_alloc();
+	ethtool_rings_set_req_set_header_dev_index(req, ifindex);
+	ethtool_rings_set_req_set_hds_thresh(req, len);
+	ret = ethtool_rings_set(ys, req);
+	if (ret < 0)
+		fprintf(stderr, "YNL failed: %s\n", ys->err.msg);
+	ethtool_rings_set_req_free(req);
+
+	if (ret == 0) {
+		get_req = ethtool_rings_get_req_alloc();
+		ethtool_rings_get_req_set_header_dev_index(get_req, ifindex);
+		get_rsp = ethtool_rings_get(ys, get_req);
+		ethtool_rings_get_req_free(get_req);
+		if (get_rsp)
+			fprintf(stderr, "HDS threshold: %d\n",
+				get_rsp->hds_thresh);
+		ethtool_rings_get_rsp_free(get_rsp);
+	}
+
+	ynl_sock_destroy(ys);
+
+	return ret;
+}
+
+static int get_hds_thresh_max(void)
+{
+	struct ethtool_rings_get_req *get_req;
+	struct ethtool_rings_get_rsp *get_rsp;
+	struct ynl_error yerr;
+	unsigned int ret = 0;
+	struct ynl_sock *ys;
+
+	ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
+	if (!ys) {
+		fprintf(stderr, "YNL: %s\n", yerr.msg);
+		return -1;
+	}
+
+	get_req = ethtool_rings_get_req_alloc();
+	ethtool_rings_get_req_set_header_dev_index(get_req, ifindex);
+	get_rsp = ethtool_rings_get(ys, get_req);
+	ethtool_rings_get_req_free(get_req);
+	if (get_rsp)
+		ret = get_rsp->hds_thresh_max;
+	ethtool_rings_get_rsp_free(get_rsp);
+
+	ynl_sock_destroy(ys);
+
+	return ret;
+}
+
 static int configure_rss(void)
 {
 	return run_command("sudo ethtool -X %s equal %d >&2", ifname, start_queue);
@@ -565,6 +631,9 @@ static int do_server(struct memory_buffer *mem)
 	if (configure_headersplit(1))
 		error(1, 0, "Failed to enable TCP header split\n");
 
+	if (configure_hds_thresh(0))
+		error(1, 0, "Failed to set HDS threshold\n");
+
 	/* Configure RSS to divert all traffic from our devmem queues */
 	if (configure_rss())
 		error(1, 0, "Failed to configure rss\n");
@@ -725,10 +794,14 @@ static int do_server(struct memory_buffer *mem)
 void run_devmem_tests(void)
 {
 	struct memory_buffer *mem;
+	int hds_thresh_max = 0;
 	struct ynl_sock *ys;
 
 	mem = provider->alloc(getpagesize() * NUM_PAGES);
 
+	hds_thresh_max = get_hds_thresh_max();
+	if (hds_thresh_max < 0)
+		error(1, 0, "Failed to get hds_thresh_max");
 	/* Configure RSS to divert all traffic from our devmem queues */
 	if (configure_rss())
 		error(1, 0, "rss error\n");
@@ -750,6 +823,19 @@ void run_devmem_tests(void)
 	if (configure_headersplit(1))
 		error(1, 0, "Failed to configure header split\n");
 
+	/* Do not test hds_thresh if hds_thresh_max value is 0 */
+	if (hds_thresh_max) {
+		if (configure_hds_thresh(1))
+			error(1, 0, "Failed to configure HDS threshold\n");
+
+		if (!bind_rx_queue(ifindex, mem->fd, create_queues(),
+				   num_queues, &ys))
+			error(1, 0, "Configure dmabuf with non-zero HDS threshold should have failed\n");
+
+		if (configure_hds_thresh(0))
+			error(1, 0, "Failed to configure HDS threshold\n");
+	}
+
 	if (bind_rx_queue(ifindex, mem->fd, create_queues(), num_queues, &ys))
 		error(1, 0, "Failed to bind\n");
 
-- 
2.34.1

Re: [PATCH net-next] selftests: devmem: configure HDS threshold

[Stanislav Fomichev]

On 06/30, Taehee Yoo wrote:
> The devmem TCP requires the hds-thresh value to be 0, but it doesn't
> change it automatically.
> Therefore, configure_hds_thresh() is added to handle this.
> 
> The run_devmem_tests() now tests hds_thresh, but it skips test if the
> hds_thresh_max value is 0.
> 
> Signed-off-by: Taehee Yoo <ap420073@gmail.com>
> ---
>  .../selftests/drivers/net/hw/ncdevmem.c       | 86 +++++++++++++++++++
>  1 file changed, 86 insertions(+)
> 
> diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> index cc9b40d9c5d5..d78b5e5697d7 100644
> --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> @@ -349,6 +349,72 @@ static int configure_headersplit(bool on)
>  	return ret;
>  }
>  
> +static int configure_hds_thresh(int len)
> +{
> +	struct ethtool_rings_get_req *get_req;
> +	struct ethtool_rings_get_rsp *get_rsp;
> +	struct ethtool_rings_set_req *req;
> +	struct ynl_error yerr;
> +	struct ynl_sock *ys;
> +	int ret;
> +
> +	ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
> +	if (!ys) {
> +		fprintf(stderr, "YNL: %s\n", yerr.msg);
> +		return -1;
> +	}
> +
> +	req = ethtool_rings_set_req_alloc();
> +	ethtool_rings_set_req_set_header_dev_index(req, ifindex);

[..]

> +	ethtool_rings_set_req_set_hds_thresh(req, len);

Any reason not to add this to the existing configure_headersplit? Is it
only for tests?

Re: [PATCH net-next] selftests: devmem: configure HDS threshold

[Mina Almasry]

On Mon, Jun 30, 2025 at 2:28 AM Taehee Yoo <ap420073@gmail.com> wrote:
>
> The devmem TCP requires the hds-thresh value to be 0, but it doesn't
> change it automatically.
> Therefore, configure_hds_thresh() is added to handle this.
>
> The run_devmem_tests() now tests hds_thresh, but it skips test if the
> hds_thresh_max value is 0.
>
> Signed-off-by: Taehee Yoo <ap420073@gmail.com>
> ---
>  .../selftests/drivers/net/hw/ncdevmem.c       | 86 +++++++++++++++++++
>  1 file changed, 86 insertions(+)
>
> diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> index cc9b40d9c5d5..d78b5e5697d7 100644
> --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> @@ -349,6 +349,72 @@ static int configure_headersplit(bool on)
>         return ret;
>  }
>
> +static int configure_hds_thresh(int len)
> +{
> +       struct ethtool_rings_get_req *get_req;
> +       struct ethtool_rings_get_rsp *get_rsp;
> +       struct ethtool_rings_set_req *req;
> +       struct ynl_error yerr;
> +       struct ynl_sock *ys;
> +       int ret;
> +
> +       ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
> +       if (!ys) {
> +               fprintf(stderr, "YNL: %s\n", yerr.msg);
> +               return -1;
> +       }
> +
> +       req = ethtool_rings_set_req_alloc();
> +       ethtool_rings_set_req_set_header_dev_index(req, ifindex);
> +       ethtool_rings_set_req_set_hds_thresh(req, len);
> +       ret = ethtool_rings_set(ys, req);
> +       if (ret < 0)
> +               fprintf(stderr, "YNL failed: %s\n", ys->err.msg);
> +       ethtool_rings_set_req_free(req);
> +
> +       if (ret == 0) {
> +               get_req = ethtool_rings_get_req_alloc();
> +               ethtool_rings_get_req_set_header_dev_index(get_req, ifindex);
> +               get_rsp = ethtool_rings_get(ys, get_req);
> +               ethtool_rings_get_req_free(get_req);
> +               if (get_rsp)
> +                       fprintf(stderr, "HDS threshold: %d\n",
> +                               get_rsp->hds_thresh);
> +               ethtool_rings_get_rsp_free(get_rsp);
> +       }
> +
> +       ynl_sock_destroy(ys);
> +
> +       return ret;
> +}
> +
> +static int get_hds_thresh_max(void)
> +{
> +       struct ethtool_rings_get_req *get_req;
> +       struct ethtool_rings_get_rsp *get_rsp;
> +       struct ynl_error yerr;
> +       unsigned int ret = 0;
> +       struct ynl_sock *ys;
> +
> +       ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
> +       if (!ys) {
> +               fprintf(stderr, "YNL: %s\n", yerr.msg);
> +               return -1;
> +       }
> +
> +       get_req = ethtool_rings_get_req_alloc();
> +       ethtool_rings_get_req_set_header_dev_index(get_req, ifindex);
> +       get_rsp = ethtool_rings_get(ys, get_req);
> +       ethtool_rings_get_req_free(get_req);
> +       if (get_rsp)
> +               ret = get_rsp->hds_thresh_max;
> +       ethtool_rings_get_rsp_free(get_rsp);
> +
> +       ynl_sock_destroy(ys);
> +
> +       return ret;
> +}
> +
>  static int configure_rss(void)
>  {
>         return run_command("sudo ethtool -X %s equal %d >&2", ifname, start_queue);
> @@ -565,6 +631,9 @@ static int do_server(struct memory_buffer *mem)
>         if (configure_headersplit(1))
>                 error(1, 0, "Failed to enable TCP header split\n");
>
> +       if (configure_hds_thresh(0))
> +               error(1, 0, "Failed to set HDS threshold\n");
> +

hds_thresh should probably be part of configuring headersplit.

But also, failing to set hds_thresh should not fail the test, to
maintain compatibility with drivers that don't support configuring
hds_thresh.

Re: [PATCH net-next] selftests: devmem: configure HDS threshold

[Taehee Yoo]

On Tue, Jul 1, 2025 at 12:09 AM Stanislav Fomichev <stfomichev@gmail.com> wrote:
>

Hi Stanislav,
Thanks a lot for your review!

> On 06/30, Taehee Yoo wrote:
> > The devmem TCP requires the hds-thresh value to be 0, but it doesn't
> > change it automatically.
> > Therefore, configure_hds_thresh() is added to handle this.
> >
> > The run_devmem_tests() now tests hds_thresh, but it skips test if the
> > hds_thresh_max value is 0.
> >
> > Signed-off-by: Taehee Yoo <ap420073@gmail.com>
> > ---
> >  .../selftests/drivers/net/hw/ncdevmem.c       | 86 +++++++++++++++++++
> >  1 file changed, 86 insertions(+)
> >
> > diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > index cc9b40d9c5d5..d78b5e5697d7 100644
> > --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > @@ -349,6 +349,72 @@ static int configure_headersplit(bool on)
> >       return ret;
> >  }
> >
> > +static int configure_hds_thresh(int len)
> > +{
> > +     struct ethtool_rings_get_req *get_req;
> > +     struct ethtool_rings_get_rsp *get_rsp;
> > +     struct ethtool_rings_set_req *req;
> > +     struct ynl_error yerr;
> > +     struct ynl_sock *ys;
> > +     int ret;
> > +
> > +     ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
> > +     if (!ys) {
> > +             fprintf(stderr, "YNL: %s\n", yerr.msg);
> > +             return -1;
> > +     }
> > +
> > +     req = ethtool_rings_set_req_alloc();
> > +     ethtool_rings_set_req_set_header_dev_index(req, ifindex);
>
> [..]
>
> > +     ethtool_rings_set_req_set_hds_thresh(req, len);
>
> Any reason not to add this to the existing configure_headersplit? Is it
> only for tests?

Yes, I thought testing code requires a separate function.
If a hds-thresh testing is not required, I think adding setting
hds-thresh value into configure_headersplit().

Thanks a lot!
Taehee Yoo

Re: [PATCH net-next] selftests: devmem: configure HDS threshold

[Taehee Yoo]

On Tue, Jul 1, 2025 at 1:12 AM Mina Almasry <almasrymina@google.com> wrote:
>

Hi Mina,
Thanks a lot for your review!

> On Mon, Jun 30, 2025 at 2:28 AM Taehee Yoo <ap420073@gmail.com> wrote:
> >
> > The devmem TCP requires the hds-thresh value to be 0, but it doesn't
> > change it automatically.
> > Therefore, configure_hds_thresh() is added to handle this.
> >
> > The run_devmem_tests() now tests hds_thresh, but it skips test if the
> > hds_thresh_max value is 0.
> >
> > Signed-off-by: Taehee Yoo <ap420073@gmail.com>
> > ---
> >  .../selftests/drivers/net/hw/ncdevmem.c       | 86 +++++++++++++++++++
> >  1 file changed, 86 insertions(+)
> >
> > diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > index cc9b40d9c5d5..d78b5e5697d7 100644
> > --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > @@ -349,6 +349,72 @@ static int configure_headersplit(bool on)
> >         return ret;
> >  }
> >
> > +static int configure_hds_thresh(int len)
> > +{
> > +       struct ethtool_rings_get_req *get_req;
> > +       struct ethtool_rings_get_rsp *get_rsp;
> > +       struct ethtool_rings_set_req *req;
> > +       struct ynl_error yerr;
> > +       struct ynl_sock *ys;
> > +       int ret;
> > +
> > +       ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
> > +       if (!ys) {
> > +               fprintf(stderr, "YNL: %s\n", yerr.msg);
> > +               return -1;
> > +       }
> > +
> > +       req = ethtool_rings_set_req_alloc();
> > +       ethtool_rings_set_req_set_header_dev_index(req, ifindex);
> > +       ethtool_rings_set_req_set_hds_thresh(req, len);
> > +       ret = ethtool_rings_set(ys, req);
> > +       if (ret < 0)
> > +               fprintf(stderr, "YNL failed: %s\n", ys->err.msg);
> > +       ethtool_rings_set_req_free(req);
> > +
> > +       if (ret == 0) {
> > +               get_req = ethtool_rings_get_req_alloc();
> > +               ethtool_rings_get_req_set_header_dev_index(get_req, ifindex);
> > +               get_rsp = ethtool_rings_get(ys, get_req);
> > +               ethtool_rings_get_req_free(get_req);
> > +               if (get_rsp)
> > +                       fprintf(stderr, "HDS threshold: %d\n",
> > +                               get_rsp->hds_thresh);
> > +               ethtool_rings_get_rsp_free(get_rsp);
> > +       }
> > +
> > +       ynl_sock_destroy(ys);
> > +
> > +       return ret;
> > +}
> > +
> > +static int get_hds_thresh_max(void)
> > +{
> > +       struct ethtool_rings_get_req *get_req;
> > +       struct ethtool_rings_get_rsp *get_rsp;
> > +       struct ynl_error yerr;
> > +       unsigned int ret = 0;
> > +       struct ynl_sock *ys;
> > +
> > +       ys = ynl_sock_create(&ynl_ethtool_family, &yerr);
> > +       if (!ys) {
> > +               fprintf(stderr, "YNL: %s\n", yerr.msg);
> > +               return -1;
> > +       }
> > +
> > +       get_req = ethtool_rings_get_req_alloc();
> > +       ethtool_rings_get_req_set_header_dev_index(get_req, ifindex);
> > +       get_rsp = ethtool_rings_get(ys, get_req);
> > +       ethtool_rings_get_req_free(get_req);
> > +       if (get_rsp)
> > +               ret = get_rsp->hds_thresh_max;
> > +       ethtool_rings_get_rsp_free(get_rsp);
> > +
> > +       ynl_sock_destroy(ys);
> > +
> > +       return ret;
> > +}
> > +
> >  static int configure_rss(void)
> >  {
> >         return run_command("sudo ethtool -X %s equal %d >&2", ifname, start_queue);
> > @@ -565,6 +631,9 @@ static int do_server(struct memory_buffer *mem)
> >         if (configure_headersplit(1))
> >                 error(1, 0, "Failed to enable TCP header split\n");
> >
> > +       if (configure_hds_thresh(0))
> > +               error(1, 0, "Failed to set HDS threshold\n");
> > +
>
> hds_thresh should probably be part of configuring headersplit.
>
> But also, failing to set hds_thresh should not fail the test, to
> maintain compatibility with drivers that don't support configuring
> hds_thresh.

Okay, I will add the setting hds-thresh part into
configure_headersplit(). hds-thresh value will be set to 0 when
tcp-data-split is being enabled.

Thanks a lot!
Taehee Yoo