[net-next v4 0/2] devlink: Add port function attribute for IO EQs

[net-next v4 0/2] devlink: Add port function attribute for IO EQs

[Parav Pandit]

Currently, PCI SFs and VFs use IO event queues to deliver netdev per
channel events. The number of netdev channels is a function of IO
event queues. In the second scenario of an RDMA device, the
completion vectors are also a function of IO event queues. Currently, an
administrator on the hypervisor has no means to provision the number
of IO event queues for the SF device or the VF device. Device/firmware
determines some arbitrary value for these IO event queues. Due to this,
the SF netdev channels are unpredictable, and consequently, the
performance is too.

This short series introduces a new port function attribute: max_io_eqs.
The goal is to provide administrators at the hypervisor level with the
ability to provision the maximum number of IO event queues for a
function. This gives the control to the administrator to provision
right number of IO event queues and have predictable performance.

Examples of when an administrator provisions (set) maximum number of
IO event queues when using switchdev mode:

  $ devlink port show pci/0000:06:00.0/1
      pci/0000:06:00.0/1: type eth netdev enp6s0pf0vf0 flavour pcivf pfnum 0 vfnum 0
          function:
          hw_addr 00:00:00:00:00:00 roce enable max_io_eqs 10

  $ devlink port function set pci/0000:06:00.0/1 max_io_eqs 20

  $ devlink port show pci/0000:06:00.0/1
      pci/0000:06:00.0/1: type eth netdev enp6s0pf0vf0 flavour pcivf pfnum 0 vfnum 0
          function:
          hw_addr 00:00:00:00:00:00 roce enable max_io_eqs 20

This sets the corresponding maximum IO event queues of the function
before it is enumerated. Thus, when the VF/SF driver reads the
capability from the device, it sees the value provisioned by the
hypervisor. The driver is then able to configure the number of channels
for the net device, as well as the number of completion vectors
for the RDMA device. The device/firmware also honors the provisioned
value, hence any VF/SF driver attempting to create IO EQs
beyond provisioned value results in an error.

With above setting now, the administrator is able to achieve the 2x
performance on SFs with 20 channels. In second example when SF was
provisioned for a container with 2 cpus, the administrator provisioned only
2 IO event queues, thereby saving device resources.

With the above settings now in place, the administrator achieved 2x
performance with the SF device with 20 channels. In the second example,
when the SF was provisioned for a container with 2 CPUs, the administrator
provisioned only 2 IO event queues, thereby saving device resources.

changelog:
v2->v3:
- limited to 80 chars per line in devlink
- fixed comments from Jakub in mlx5 driver to fix missing mutex unlock
  on error path
v1->v2:
- limited comment to 80 chars per line in header file
- fixed set function variables for reverse christmas tree
- fixed comments from Kalesh
- fixed missing kfree in get call
- returning error code for get cmd failure
- fixed error msg copy paste error in set on cmd failure

Parav Pandit (2):
  devlink: Support setting max_io_eqs
  mlx5/core: Support max_io_eqs for a function

 .../networking/devlink/devlink-port.rst       | 33 +++++++
 .../mellanox/mlx5/core/esw/devlink_port.c     |  4 +
 .../net/ethernet/mellanox/mlx5/core/eswitch.h |  7 ++
 .../mellanox/mlx5/core/eswitch_offloads.c     | 97 +++++++++++++++++++
 include/net/devlink.h                         | 14 +++
 include/uapi/linux/devlink.h                  |  1 +
 net/devlink/port.c                            | 53 ++++++++++
 7 files changed, 209 insertions(+)

-- 
2.26.2

[net-next v4 1/2] devlink: Support setting max_io_eqs

[Parav Pandit]

Many devices send event notifications for the IO queues,
such as tx and rx queues, through event queues.

Enable a privileged owner, such as a hypervisor PF, to set the number
of IO event queues for the VF and SF during the provisioning stage.

example:
Get maximum IO event queues of the VF device::

  $ devlink port show pci/0000:06:00.0/2
  pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1
      function:
          hw_addr 00:00:00:00:00:00 ipsec_packet disabled max_io_eqs 10

Set maximum IO event queues of the VF device::

  $ devlink port function set pci/0000:06:00.0/2 max_io_eqs 32

  $ devlink port show pci/0000:06:00.0/2
  pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1
      function:
          hw_addr 00:00:00:00:00:00 ipsec_packet disabled max_io_eqs 32

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
---
changelog:
v3->v4:
- addressed comment from Jakub to improve devlink documentation
v2->v3:
- limited 80 chars per line
v1->v2:
- limited comment to 80 chars per line in header file
---
 .../networking/devlink/devlink-port.rst       | 33 ++++++++++++
 include/net/devlink.h                         | 14 +++++
 include/uapi/linux/devlink.h                  |  1 +
 net/devlink/port.c                            | 53 +++++++++++++++++++
 4 files changed, 101 insertions(+)

diff --git a/Documentation/networking/devlink/devlink-port.rst b/Documentation/networking/devlink/devlink-port.rst
index 562f46b41274..9d22d41a7cd1 100644
--- a/Documentation/networking/devlink/devlink-port.rst
+++ b/Documentation/networking/devlink/devlink-port.rst
@@ -134,6 +134,9 @@ Users may also set the IPsec crypto capability of the function using
 Users may also set the IPsec packet capability of the function using
 `devlink port function set ipsec_packet` command.
 
+Users may also set the maximum IO event queues of the function
+using `devlink port function set max_io_eqs` command.
+
 Function attributes
 ===================
 
@@ -295,6 +298,36 @@ policy is processed in software by the kernel.
         function:
             hw_addr 00:00:00:00:00:00 ipsec_packet enabled
 
+Maximum IO events queues setup
+------------------------------
+When user sets maximum number of IO event queues for a SF or
+a VF, such function driver is limited to consume only enforced
+number of IO event queues.
+
+IO event queues deliver events related to IO queues, including network
+device transmit and receive queues (txq and rxq) and RDMA Queue Pairs (QPs).
+For example, the number of netdevice channels and RDMA device completion
+vectors are derived from the function's IO event queues. Usually, the number
+of interrupt vectors consumed by the driver is limited by the number of IO
+event queues per device, as each of the IO event queues is connected to an
+interrupt vector.
+
+- Get maximum IO event queues of the VF device::
+
+    $ devlink port show pci/0000:06:00.0/2
+    pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1
+        function:
+            hw_addr 00:00:00:00:00:00 ipsec_packet disabled max_io_eqs 10
+
+- Set maximum IO event queues of the VF device::
+
+    $ devlink port function set pci/0000:06:00.0/2 max_io_eqs 32
+
+    $ devlink port show pci/0000:06:00.0/2
+    pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1
+        function:
+            hw_addr 00:00:00:00:00:00 ipsec_packet disabled max_io_eqs 32
+
 Subfunction
 ============
 
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 9ac394bdfbe4..bb1af599d101 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1602,6 +1602,14 @@ void devlink_free(struct devlink *devlink);
  *			      capability. Should be used by device drivers to
  *			      enable/disable ipsec_packet capability of a
  *			      function managed by the devlink port.
+ * @port_fn_max_io_eqs_get: Callback used to get port function's maximum number
+ *			    of event queues. Should be used by device drivers to
+ *			    report the maximum event queues of a function
+ *			    managed by the devlink port.
+ * @port_fn_max_io_eqs_set: Callback used to set port function's maximum number
+ *			    of event queues. Should be used by device drivers to
+ *			    configure maximum number of event queues
+ *			    of a function managed by the devlink port.
  *
  * Note: Driver should return -EOPNOTSUPP if it doesn't support
  * port function (@port_fn_*) handling for a particular port.
@@ -1651,6 +1659,12 @@ struct devlink_port_ops {
 	int (*port_fn_ipsec_packet_set)(struct devlink_port *devlink_port,
 					bool enable,
 					struct netlink_ext_ack *extack);
+	int (*port_fn_max_io_eqs_get)(struct devlink_port *devlink_port,
+				      u32 *max_eqs,
+				      struct netlink_ext_ack *extack);
+	int (*port_fn_max_io_eqs_set)(struct devlink_port *devlink_port,
+				      u32 max_eqs,
+				      struct netlink_ext_ack *extack);
 };
 
 void devlink_port_init(struct devlink *devlink,
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 2da0c7eb6710..9401aa343673 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -686,6 +686,7 @@ enum devlink_port_function_attr {
 	DEVLINK_PORT_FN_ATTR_OPSTATE,	/* u8 */
 	DEVLINK_PORT_FN_ATTR_CAPS,	/* bitfield32 */
 	DEVLINK_PORT_FN_ATTR_DEVLINK,	/* nested */
+	DEVLINK_PORT_FN_ATTR_MAX_IO_EQS,	/* u32 */
 
 	__DEVLINK_PORT_FUNCTION_ATTR_MAX,
 	DEVLINK_PORT_FUNCTION_ATTR_MAX = __DEVLINK_PORT_FUNCTION_ATTR_MAX - 1
diff --git a/net/devlink/port.c b/net/devlink/port.c
index 118d130d2afd..be9158b4453c 100644
--- a/net/devlink/port.c
+++ b/net/devlink/port.c
@@ -16,6 +16,7 @@ static const struct nla_policy devlink_function_nl_policy[DEVLINK_PORT_FUNCTION_
 				 DEVLINK_PORT_FN_STATE_ACTIVE),
 	[DEVLINK_PORT_FN_ATTR_CAPS] =
 		NLA_POLICY_BITFIELD32(DEVLINK_PORT_FN_CAPS_VALID_MASK),
+	[DEVLINK_PORT_FN_ATTR_MAX_IO_EQS] = { .type = NLA_U32 },
 };
 
 #define ASSERT_DEVLINK_PORT_REGISTERED(devlink_port)				\
@@ -182,6 +183,30 @@ static int devlink_port_fn_caps_fill(struct devlink_port *devlink_port,
 	return 0;
 }
 
+static int devlink_port_fn_max_io_eqs_fill(struct devlink_port *port,
+					   struct sk_buff *msg,
+					   struct netlink_ext_ack *extack,
+					   bool *msg_updated)
+{
+	u32 max_io_eqs;
+	int err;
+
+	if (!port->ops->port_fn_max_io_eqs_get)
+		return 0;
+
+	err = port->ops->port_fn_max_io_eqs_get(port, &max_io_eqs, extack);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return 0;
+		return err;
+	}
+	err = nla_put_u32(msg, DEVLINK_PORT_FN_ATTR_MAX_IO_EQS, max_io_eqs);
+	if (err)
+		return err;
+	*msg_updated = true;
+	return 0;
+}
+
 int devlink_nl_port_handle_fill(struct sk_buff *msg, struct devlink_port *devlink_port)
 {
 	if (devlink_nl_put_handle(msg, devlink_port->devlink))
@@ -409,6 +434,18 @@ static int devlink_port_fn_caps_set(struct devlink_port *devlink_port,
 	return 0;
 }
 
+static int
+devlink_port_fn_max_io_eqs_set(struct devlink_port *devlink_port,
+			       const struct nlattr *attr,
+			       struct netlink_ext_ack *extack)
+{
+	u32 max_io_eqs;
+
+	max_io_eqs = nla_get_u32(attr);
+	return devlink_port->ops->port_fn_max_io_eqs_set(devlink_port,
+							 max_io_eqs, extack);
+}
+
 static int
 devlink_nl_port_function_attrs_put(struct sk_buff *msg, struct devlink_port *port,
 				   struct netlink_ext_ack *extack)
@@ -428,6 +465,9 @@ devlink_nl_port_function_attrs_put(struct sk_buff *msg, struct devlink_port *por
 	if (err)
 		goto out;
 	err = devlink_port_fn_state_fill(port, msg, extack, &msg_updated);
+	if (err)
+		goto out;
+	err = devlink_port_fn_max_io_eqs_fill(port, msg, extack, &msg_updated);
 	if (err)
 		goto out;
 	err = devlink_rel_devlink_handle_put(msg, port->devlink,
@@ -726,6 +766,12 @@ static int devlink_port_function_validate(struct devlink_port *devlink_port,
 			}
 		}
 	}
+	if (tb[DEVLINK_PORT_FN_ATTR_MAX_IO_EQS] &&
+	    !ops->port_fn_max_io_eqs_set) {
+		NL_SET_ERR_MSG_ATTR(extack, tb[DEVLINK_PORT_FN_ATTR_MAX_IO_EQS],
+				    "Function does not support max_io_eqs setting");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
@@ -761,6 +807,13 @@ static int devlink_port_function_set(struct devlink_port *port,
 			return err;
 	}
 
+	attr = tb[DEVLINK_PORT_FN_ATTR_MAX_IO_EQS];
+	if (attr) {
+		err = devlink_port_fn_max_io_eqs_set(port, attr, extack);
+		if (err)
+			return err;
+	}
+
 	/* Keep this as the last function attribute set, so that when
 	 * multiple port function attributes are set along with state,
 	 * Those can be applied first before activating the state.
-- 
2.26.2

[net-next v4 2/2] mlx5/core: Support max_io_eqs for a function

[Parav Pandit]

Implement get and set for the maximum IO event queues for SF and VF.
This enables administrator on the hypervisor to control the maximum
IO event queues which are typically used to derive the maximum and
default number of net device channels or rdma device completion vectors.

Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
---
changelog:
v3->v4:
- addressed comment from David
- replaced open coded overflow check with kernel api
v2->v3:
- limited to 80 chars per line in devlink
- fixed comments from Jakub in mlx5 driver to fix missing mutex unlock
  on error path
v1->v2:
- fixed comments from Kalesh
- fixed missing kfree in get call
- returning error code for get cmd failure
- fixed error msg copy paste error in set on cmd failure
- limited code to 80 chars limit
- fixed set function variables for reverse christmas tree

---
 .../mellanox/mlx5/core/esw/devlink_port.c     |  4 +
 .../net/ethernet/mellanox/mlx5/core/eswitch.h |  7 ++
 .../mellanox/mlx5/core/eswitch_offloads.c     | 97 +++++++++++++++++++
 3 files changed, 108 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c
index d8e739cbcbce..f8869c9b6802 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c
@@ -98,6 +98,8 @@ static const struct devlink_port_ops mlx5_esw_pf_vf_dl_port_ops = {
 	.port_fn_ipsec_packet_get = mlx5_devlink_port_fn_ipsec_packet_get,
 	.port_fn_ipsec_packet_set = mlx5_devlink_port_fn_ipsec_packet_set,
 #endif /* CONFIG_XFRM_OFFLOAD */
+	.port_fn_max_io_eqs_get = mlx5_devlink_port_fn_max_io_eqs_get,
+	.port_fn_max_io_eqs_set = mlx5_devlink_port_fn_max_io_eqs_set,
 };
 
 static void mlx5_esw_offloads_sf_devlink_port_attrs_set(struct mlx5_eswitch *esw,
@@ -143,6 +145,8 @@ static const struct devlink_port_ops mlx5_esw_dl_sf_port_ops = {
 	.port_fn_state_get = mlx5_devlink_sf_port_fn_state_get,
 	.port_fn_state_set = mlx5_devlink_sf_port_fn_state_set,
 #endif
+	.port_fn_max_io_eqs_get = mlx5_devlink_port_fn_max_io_eqs_get,
+	.port_fn_max_io_eqs_set = mlx5_devlink_port_fn_max_io_eqs_set,
 };
 
 int mlx5_esw_offloads_devlink_port_register(struct mlx5_eswitch *esw, struct mlx5_vport *vport)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h
index 349e28a6dd8d..50ce1ea20dd4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h
@@ -573,6 +573,13 @@ int mlx5_devlink_port_fn_ipsec_packet_get(struct devlink_port *port, bool *is_en
 int mlx5_devlink_port_fn_ipsec_packet_set(struct devlink_port *port, bool enable,
 					  struct netlink_ext_ack *extack);
 #endif /* CONFIG_XFRM_OFFLOAD */
+int mlx5_devlink_port_fn_max_io_eqs_get(struct devlink_port *port,
+					u32 *max_io_eqs,
+					struct netlink_ext_ack *extack);
+int mlx5_devlink_port_fn_max_io_eqs_set(struct devlink_port *port,
+					u32 max_io_eqs,
+					struct netlink_ext_ack *extack);
+
 void *mlx5_eswitch_get_uplink_priv(struct mlx5_eswitch *esw, u8 rep_type);
 
 int __mlx5_eswitch_set_vport_vlan(struct mlx5_eswitch *esw,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index baaae628b0a0..20927f65ac2c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -66,6 +66,8 @@
 
 #define MLX5_ESW_FT_OFFLOADS_DROP_RULE (1)
 
+#define MLX5_ESW_MAX_CTRL_EQS 4
+
 static struct esw_vport_tbl_namespace mlx5_esw_vport_tbl_mirror_ns = {
 	.max_fte = MLX5_ESW_VPORT_TBL_SIZE,
 	.max_num_groups = MLX5_ESW_VPORT_TBL_NUM_GROUPS,
@@ -4557,3 +4559,98 @@ int mlx5_devlink_port_fn_ipsec_packet_set(struct devlink_port *port,
 	return err;
 }
 #endif /* CONFIG_XFRM_OFFLOAD */
+
+int
+mlx5_devlink_port_fn_max_io_eqs_get(struct devlink_port *port, u32 *max_io_eqs,
+				    struct netlink_ext_ack *extack)
+{
+	struct mlx5_vport *vport = mlx5_devlink_port_vport_get(port);
+	int query_out_sz = MLX5_ST_SZ_BYTES(query_hca_cap_out);
+	u16 vport_num = vport->vport;
+	struct mlx5_eswitch *esw;
+	void *query_ctx;
+	void *hca_caps;
+	u32 max_eqs;
+	int err;
+
+	esw = mlx5_devlink_eswitch_nocheck_get(port->devlink);
+	if (!MLX5_CAP_GEN(esw->dev, vhca_resource_manager)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Device doesn't support VHCA management");
+		return -EOPNOTSUPP;
+	}
+
+	query_ctx = kzalloc(query_out_sz, GFP_KERNEL);
+	if (!query_ctx)
+		return -ENOMEM;
+
+	mutex_lock(&esw->state_lock);
+	err = mlx5_vport_get_other_func_cap(esw->dev, vport_num, query_ctx,
+					    MLX5_CAP_GENERAL);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed getting HCA caps");
+		goto out;
+	}
+
+	hca_caps = MLX5_ADDR_OF(query_hca_cap_out, query_ctx, capability);
+	max_eqs = MLX5_GET(cmd_hca_cap, hca_caps, max_num_eqs);
+	if (max_eqs < MLX5_ESW_MAX_CTRL_EQS)
+		*max_io_eqs = 0;
+	else
+		*max_io_eqs = max_eqs - MLX5_ESW_MAX_CTRL_EQS;
+out:
+	mutex_unlock(&esw->state_lock);
+	kfree(query_ctx);
+	return err;
+}
+
+int
+mlx5_devlink_port_fn_max_io_eqs_set(struct devlink_port *port, u32 max_io_eqs,
+				    struct netlink_ext_ack *extack)
+{
+	struct mlx5_vport *vport = mlx5_devlink_port_vport_get(port);
+	int query_out_sz = MLX5_ST_SZ_BYTES(query_hca_cap_out);
+	u16 vport_num = vport->vport;
+	struct mlx5_eswitch *esw;
+	void *query_ctx;
+	void *hca_caps;
+	u16 max_eqs;
+	int err;
+
+	esw = mlx5_devlink_eswitch_nocheck_get(port->devlink);
+	if (!MLX5_CAP_GEN(esw->dev, vhca_resource_manager)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Device doesn't support VHCA management");
+		return -EOPNOTSUPP;
+	}
+
+	if (check_add_overflow(max_io_eqs, MLX5_ESW_MAX_CTRL_EQS, &max_eqs)) {
+		NL_SET_ERR_MSG_MOD(extack, "Supplied value out of range");
+		return -EINVAL;
+	}
+
+	query_ctx = kzalloc(query_out_sz, GFP_KERNEL);
+	if (!query_ctx)
+		return -ENOMEM;
+
+	mutex_lock(&esw->state_lock);
+	err = mlx5_vport_get_other_func_cap(esw->dev, vport_num, query_ctx,
+					    MLX5_CAP_GENERAL);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed getting HCA caps");
+		goto out;
+	}
+
+	hca_caps = MLX5_ADDR_OF(query_hca_cap_out, query_ctx, capability);
+	MLX5_SET(cmd_hca_cap, hca_caps, max_num_eqs, max_eqs);
+
+	err = mlx5_vport_set_other_func_cap(esw->dev, hca_caps, vport_num,
+					    MLX5_SET_HCA_CAP_OP_MOD_GENERAL_DEVICE);
+	if (err)
+		NL_SET_ERR_MSG_MOD(extack, "Failed setting HCA caps");
+
+out:
+	mutex_unlock(&esw->state_lock);
+	kfree(query_ctx);
+	return err;
+}
-- 
2.26.2

Re: [net-next v4 0/2] devlink: Add port function attribute for IO EQs

[Zhu Yanjun]

在 2024/4/6 3:05, Parav Pandit 写道:
> Currently, PCI SFs and VFs use IO event queues to deliver netdev per
> channel events. The number of netdev channels is a function of IO
> event queues. In the second scenario of an RDMA device, the
> completion vectors are also a function of IO event queues. Currently, an
> administrator on the hypervisor has no means to provision the number
> of IO event queues for the SF device or the VF device. Device/firmware
> determines some arbitrary value for these IO event queues. Due to this,
> the SF netdev channels are unpredictable, and consequently, the
> performance is too.
> 
> This short series introduces a new port function attribute: max_io_eqs.
> The goal is to provide administrators at the hypervisor level with the
> ability to provision the maximum number of IO event queues for a
> function. This gives the control to the administrator to provision
> right number of IO event queues and have predictable performance.
> 
> Examples of when an administrator provisions (set) maximum number of
> IO event queues when using switchdev mode:
> 
>    $ devlink port show pci/0000:06:00.0/1
>        pci/0000:06:00.0/1: type eth netdev enp6s0pf0vf0 flavour pcivf pfnum 0 vfnum 0
>            function:
>            hw_addr 00:00:00:00:00:00 roce enable max_io_eqs 10
> 
>    $ devlink port function set pci/0000:06:00.0/1 max_io_eqs 20
> 
>    $ devlink port show pci/0000:06:00.0/1
>        pci/0000:06:00.0/1: type eth netdev enp6s0pf0vf0 flavour pcivf pfnum 0 vfnum 0
>            function:
>            hw_addr 00:00:00:00:00:00 roce enable max_io_eqs 20
> 
> This sets the corresponding maximum IO event queues of the function
> before it is enumerated. Thus, when the VF/SF driver reads the
> capability from the device, it sees the value provisioned by the
> hypervisor. The driver is then able to configure the number of channels
> for the net device, as well as the number of completion vectors
> for the RDMA device. The device/firmware also honors the provisioned
> value, hence any VF/SF driver attempting to create IO EQs
> beyond provisioned value results in an error.
> 
> With above setting now, the administrator is able to achieve the 2x
> performance on SFs with 20 channels. In second example when SF was
> provisioned for a container with 2 cpus, the administrator provisioned only
> 2 IO event queues, thereby saving device resources.
> 

The following paragraph is the same with the above paragraph?

> With the above settings now in place, the administrator achieved 2x
> performance with the SF device with 20 channels. In the second example,
> when the SF was provisioned for a container with 2 CPUs, the administrator
> provisioned only 2 IO event queues, thereby saving device resources.
> 
> changelog:
> v2->v3:
> - limited to 80 chars per line in devlink
> - fixed comments from Jakub in mlx5 driver to fix missing mutex unlock
>    on error path
> v1->v2:
> - limited comment to 80 chars per line in header file
> - fixed set function variables for reverse christmas tree
> - fixed comments from Kalesh
> - fixed missing kfree in get call
> - returning error code for get cmd failure
> - fixed error msg copy paste error in set on cmd failure
> 
> Parav Pandit (2):
>    devlink: Support setting max_io_eqs
>    mlx5/core: Support max_io_eqs for a function
> 
>   .../networking/devlink/devlink-port.rst       | 33 +++++++
>   .../mellanox/mlx5/core/esw/devlink_port.c     |  4 +
>   .../net/ethernet/mellanox/mlx5/core/eswitch.h |  7 ++
>   .../mellanox/mlx5/core/eswitch_offloads.c     | 97 +++++++++++++++++++
>   include/net/devlink.h                         | 14 +++
>   include/uapi/linux/devlink.h                  |  1 +
>   net/devlink/port.c                            | 53 ++++++++++
>   7 files changed, 209 insertions(+)
> 

Re: [net-next v4 2/2] mlx5/core: Support max_io_eqs for a function

[David Wei]

On 2024-04-05 6:05 pm, Parav Pandit wrote:
> Implement get and set for the maximum IO event queues for SF and VF.
> This enables administrator on the hypervisor to control the maximum
> IO event queues which are typically used to derive the maximum and
> default number of net device channels or rdma device completion vectors.
> 
> Reviewed-by: Shay Drory <shayd@nvidia.com>
> Signed-off-by: Parav Pandit <parav@nvidia.com>
> ---
> changelog:
> v3->v4:
> - addressed comment from David
> - replaced open coded overflow check with kernel api
> v2->v3:
> - limited to 80 chars per line in devlink
> - fixed comments from Jakub in mlx5 driver to fix missing mutex unlock
>   on error path
> v1->v2:
> - fixed comments from Kalesh
> - fixed missing kfree in get call
> - returning error code for get cmd failure
> - fixed error msg copy paste error in set on cmd failure
> - limited code to 80 chars limit
> - fixed set function variables for reverse christmas tree
> 
> ---
>  .../mellanox/mlx5/core/esw/devlink_port.c     |  4 +
>  .../net/ethernet/mellanox/mlx5/core/eswitch.h |  7 ++
>  .../mellanox/mlx5/core/eswitch_offloads.c     | 97 +++++++++++++++++++
>  3 files changed, 108 insertions(+)
> 

LGTM, thanks for addressing.

RE: [net-next v4 0/2] devlink: Add port function attribute for IO EQs

[Parav Pandit]

> From: Zhu Yanjun <yanjun.zhu@linux.dev>
> Sent: Saturday, April 6, 2024 2:36 PM
> 
> 在 2024/4/6 3:05, Parav Pandit 写道:
> > Currently, PCI SFs and VFs use IO event queues to deliver netdev per
> > channel events. The number of netdev channels is a function of IO
> > event queues. In the second scenario of an RDMA device, the completion
> > vectors are also a function of IO event queues. Currently, an
> > administrator on the hypervisor has no means to provision the number
> > of IO event queues for the SF device or the VF device. Device/firmware
> > determines some arbitrary value for these IO event queues. Due to
> > this, the SF netdev channels are unpredictable, and consequently, the
> > performance is too.
> >
> > This short series introduces a new port function attribute: max_io_eqs.
> > The goal is to provide administrators at the hypervisor level with the
> > ability to provision the maximum number of IO event queues for a
> > function. This gives the control to the administrator to provision
> > right number of IO event queues and have predictable performance.
> >
> > Examples of when an administrator provisions (set) maximum number of
> > IO event queues when using switchdev mode:
> >
> >    $ devlink port show pci/0000:06:00.0/1
> >        pci/0000:06:00.0/1: type eth netdev enp6s0pf0vf0 flavour pcivf pfnum
> 0 vfnum 0
> >            function:
> >            hw_addr 00:00:00:00:00:00 roce enable max_io_eqs 10
> >
> >    $ devlink port function set pci/0000:06:00.0/1 max_io_eqs 20
> >
> >    $ devlink port show pci/0000:06:00.0/1
> >        pci/0000:06:00.0/1: type eth netdev enp6s0pf0vf0 flavour pcivf pfnum
> 0 vfnum 0
> >            function:
> >            hw_addr 00:00:00:00:00:00 roce enable max_io_eqs 20
> >
> > This sets the corresponding maximum IO event queues of the function
> > before it is enumerated. Thus, when the VF/SF driver reads the
> > capability from the device, it sees the value provisioned by the
> > hypervisor. The driver is then able to configure the number of
> > channels for the net device, as well as the number of completion
> > vectors for the RDMA device. The device/firmware also honors the
> > provisioned value, hence any VF/SF driver attempting to create IO EQs
> > beyond provisioned value results in an error.
> >
> > With above setting now, the administrator is able to achieve the 2x
> > performance on SFs with 20 channels. In second example when SF was
> > provisioned for a container with 2 cpus, the administrator provisioned
> > only
> > 2 IO event queues, thereby saving device resources.
> >
> 
> The following paragraph is the same with the above paragraph?
>
Ah, yes. I forgot to remove one of them while doing minor grammar changes.

 
> > With the above settings now in place, the administrator achieved 2x
> > performance with the SF device with 20 channels. In the second
> > example, when the SF was provisioned for a container with 2 CPUs, the
> > administrator provisioned only 2 IO event queues, thereby saving device
> resources.
> >
> > changelog:
> > v2->v3:
> > - limited to 80 chars per line in devlink
> > - fixed comments from Jakub in mlx5 driver to fix missing mutex unlock
> >    on error path
> > v1->v2:
> > - limited comment to 80 chars per line in header file
> > - fixed set function variables for reverse christmas tree
> > - fixed comments from Kalesh
> > - fixed missing kfree in get call
> > - returning error code for get cmd failure
> > - fixed error msg copy paste error in set on cmd failure
> >
> > Parav Pandit (2):
> >    devlink: Support setting max_io_eqs
> >    mlx5/core: Support max_io_eqs for a function
> >
> >   .../networking/devlink/devlink-port.rst       | 33 +++++++
> >   .../mellanox/mlx5/core/esw/devlink_port.c     |  4 +
> >   .../net/ethernet/mellanox/mlx5/core/eswitch.h |  7 ++
> >   .../mellanox/mlx5/core/eswitch_offloads.c     | 97 +++++++++++++++++++
> >   include/net/devlink.h                         | 14 +++
> >   include/uapi/linux/devlink.h                  |  1 +
> >   net/devlink/port.c                            | 53 ++++++++++
> >   7 files changed, 209 insertions(+)
> >

Re: [net-next v4 2/2] mlx5/core: Support max_io_eqs for a function

[Jiri Pirko]

Sat, Apr 06, 2024 at 03:05:38AM CEST, parav@nvidia.com wrote:
>Implement get and set for the maximum IO event queues for SF and VF.
>This enables administrator on the hypervisor to control the maximum
>IO event queues which are typically used to derive the maximum and
>default number of net device channels or rdma device completion vectors.
>
>Reviewed-by: Shay Drory <shayd@nvidia.com>
>Signed-off-by: Parav Pandit <parav@nvidia.com>

Reviewed-by: Jiri Pirko <jiri@nvidia.com>

Re: [net-next v4 0/2] devlink: Add port function attribute for IO EQs

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Sat, 6 Apr 2024 04:05:36 +0300 you wrote:
> Currently, PCI SFs and VFs use IO event queues to deliver netdev per
> channel events. The number of netdev channels is a function of IO
> event queues. In the second scenario of an RDMA device, the
> completion vectors are also a function of IO event queues. Currently, an
> administrator on the hypervisor has no means to provision the number
> of IO event queues for the SF device or the VF device. Device/firmware
> determines some arbitrary value for these IO event queues. Due to this,
> the SF netdev channels are unpredictable, and consequently, the
> performance is too.
> 
> [...]

Here is the summary with links:
  - [net-next,v4,1/2] devlink: Support setting max_io_eqs
    https://git.kernel.org/netdev/net-next/c/5af3e3876d56
  - [net-next,v4,2/2] mlx5/core: Support max_io_eqs for a function
    https://git.kernel.org/netdev/net-next/c/93197c7c509d

You are awesome, thank you!
-- 
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