[PATCH RESEND net-next v14 0/5] ethtool: provide the dim profile fine-tuning channel

[PATCH RESEND net-next v14 0/5] ethtool: provide the dim profile fine-tuning channel

[Heng Qi]

The NetDIM library provides excellent acceleration for many modern
network cards. However, the default profiles of DIM limits its maximum
capabilities for different NICs, so providing a way which the NIC can
be custom configured is necessary.

Currently, the way is based on the commonly used "ethtool -C".

Please review, thank you very much!

Changelog
=====
Jakub feedback: Use RESEND to refresh the review queue.

v13->v14:
  - Make DIMLIB dependent on NET (patch 2/5).

v12->v13:
  - Rebase net-next to fix the one-line conflict.
  - Update tiny comments.
  - Config ETHTOOL_NETLINK to select DIMLIB.

v11->v12:
  - Remove the use of IS_ENABLED(DIMLIB).
  - Update Simon's htmldoc hint.

v10->v11:
  - Fix and clean up some issues from Kuba, thanks.
  - Rebase net-next/main

v9->v10:
  - Collect dim related flags/mode/work into one place.
  - Use rx_profile + tx_profile instead of four profiles.
  - Add several helps.
  - Update commit logs.

v8->v9:
  - Fix the compilation error of conflicting names of rx_profile in
    dim.h and ice driver: in dim.h, rx_profile is replaced with
    dim_rx_profile. So does tx_profile.

v7->v8:
  - Use kmemdup() instead of kzalloc()/memcpy() in dev_dim_profile_init().

v6->v7:
  - A new wrapper struct pointer is used in struct net_device.
  - Add IS_ENABLED(CONFIG_DIMLIB) to avoid compiler warnings.
  - Profile fields changed from u16 to u32.

v5->v6:
  - Place the profile in netdevice to bypass the driver.
    The interaction code of ethtool <-> kernel has not changed at all,
    only the interaction part of kernel <-> driver has changed.

v4->v5:
  - Update some snippets from Kuba.

v3->v4:
  - Some tiny updates and patch 1 only add a new comment.

v2->v3:
  - Break up the attributes to avoid the use of raw c structs.
  - Use per-device profile instead of global profile in the driver.

v1->v2:
  - Use ethtool tool instead of net-sysfs.

Heng Qi (5):
  linux/dim: move useful macros to .h file
  dim: make DIMLIB dependent on NET
  ethtool: provide customized dim profile management
  dim: add new interfaces for initialization and getting results
  virtio-net: support dim profile fine-tuning

 Documentation/netlink/specs/ethtool.yaml     |  31 +++
 Documentation/networking/ethtool-netlink.rst |   4 +
 Documentation/networking/net_dim.rst         |  42 +++
 drivers/net/virtio_net.c                     |  54 +++-
 drivers/soc/fsl/Kconfig                      |   2 +-
 include/linux/dim.h                          | 113 ++++++++
 include/linux/ethtool.h                      |   4 +-
 include/linux/netdevice.h                    |   3 +
 include/uapi/linux/ethtool_netlink.h         |  22 ++
 lib/Kconfig                                  |   1 +
 lib/dim/net_dim.c                            | 144 +++++++++-
 net/Kconfig                                  |   1 +
 net/ethtool/coalesce.c                       | 263 ++++++++++++++++++-
 13 files changed, 667 insertions(+), 17 deletions(-)

-- 
2.32.0.3.g01195cf9f

[PATCH RESEND net-next v14 1/5] linux/dim: move useful macros to .h file

[Heng Qi]

Useful macros will be used effectively elsewhere.
These will be utilized in subsequent patches.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 include/linux/dim.h | 7 +++++++
 lib/dim/net_dim.c   | 6 ------
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/linux/dim.h b/include/linux/dim.h
index f343bc9aa2ec..43398f5eade2 100644
--- a/include/linux/dim.h
+++ b/include/linux/dim.h
@@ -10,6 +10,13 @@
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
+/* Number of DIM profiles and period mode. */
+#define NET_DIM_PARAMS_NUM_PROFILES 5
+#define NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE 256
+#define NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE 128
+#define NET_DIM_DEF_PROFILE_CQE 1
+#define NET_DIM_DEF_PROFILE_EQE 1
+
 /*
  * Number of events between DIM iterations.
  * Causes a moderation of the algorithm run.
diff --git a/lib/dim/net_dim.c b/lib/dim/net_dim.c
index 4e32f7aaac86..67d5beb34dc3 100644
--- a/lib/dim/net_dim.c
+++ b/lib/dim/net_dim.c
@@ -11,12 +11,6 @@
  *        There are different set of profiles for RX/TX CQs.
  *        Each profile size must be of NET_DIM_PARAMS_NUM_PROFILES
  */
-#define NET_DIM_PARAMS_NUM_PROFILES 5
-#define NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE 256
-#define NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE 128
-#define NET_DIM_DEF_PROFILE_CQE 1
-#define NET_DIM_DEF_PROFILE_EQE 1
-
 #define NET_DIM_RX_EQE_PROFILES { \
 	{.usec = 1,   .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}, \
 	{.usec = 8,   .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}, \
-- 
2.32.0.3.g01195cf9f

Re: [PATCH RESEND net-next v14 1/5] linux/dim: move useful macros to .h file

[Simon Horman]

On Tue, Jun 18, 2024 at 10:56:40AM +0800, Heng Qi wrote:
> Useful macros will be used effectively elsewhere.
> These will be utilized in subsequent patches.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>

Reviewed-by: Simon Horman <horms@kernel.org>

[PATCH RESEND net-next v14 2/5] dim: make DIMLIB dependent on NET

[Heng Qi]

DIMLIB's capabilities are supplied by the dim, net_dim, and
rdma_dim objects, and dim's interfaces solely act as a base for
net_dim and rdma_dim and are not explicitly used anywhere else.
rdma_dim is utilized by the infiniband driver, while net_dim
is for network devices, excluding the soc/fsl driver.

In this patch, net_dim relies on some NET's interfaces, thus
DIMLIB needs to explicitly depend on the NET Kconfig.

The soc/fsl driver uses the functions provided by net_dim, so
it also needs to depend on NET.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 drivers/soc/fsl/Kconfig | 2 +-
 lib/Kconfig             | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/fsl/Kconfig b/drivers/soc/fsl/Kconfig
index fcec6ed83d5e..a1e0bc8c1757 100644
--- a/drivers/soc/fsl/Kconfig
+++ b/drivers/soc/fsl/Kconfig
@@ -22,7 +22,7 @@ config FSL_GUTS
 
 config FSL_MC_DPIO
         tristate "QorIQ DPAA2 DPIO driver"
-        depends on FSL_MC_BUS
+        depends on FSL_MC_BUS && NET
         select SOC_BUS
         select FSL_GUTS
         select DIMLIB
diff --git a/lib/Kconfig b/lib/Kconfig
index d33a268bc256..0ffc4f69564f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -629,6 +629,7 @@ config SIGNATURE
 
 config DIMLIB
 	tristate
+	depends on NET
 	help
 	  Dynamic Interrupt Moderation library.
 	  Implements an algorithm for dynamically changing CQ moderation values
-- 
2.32.0.3.g01195cf9f

Re: [PATCH RESEND net-next v14 2/5] dim: make DIMLIB dependent on NET

[Simon Horman]

On Tue, Jun 18, 2024 at 10:56:41AM +0800, Heng Qi wrote:
> DIMLIB's capabilities are supplied by the dim, net_dim, and
> rdma_dim objects, and dim's interfaces solely act as a base for
> net_dim and rdma_dim and are not explicitly used anywhere else.
> rdma_dim is utilized by the infiniband driver, while net_dim
> is for network devices, excluding the soc/fsl driver.
> 
> In this patch, net_dim relies on some NET's interfaces, thus
> DIMLIB needs to explicitly depend on the NET Kconfig.
> 
> The soc/fsl driver uses the functions provided by net_dim, so
> it also needs to depend on NET.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>

Reviewed-by: Simon Horman <horms@kernel.org>

[PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Heng Qi]

The NetDIM library, currently leveraged by an array of NICs, delivers
excellent acceleration benefits. Nevertheless, NICs vary significantly
in their dim profile list prerequisites.

Specifically, virtio-net backends may present diverse sw or hw device
implementation, making a one-size-fits-all parameter list impractical.
On Alibaba Cloud, the virtio DPU's performance under the default DIM
profile falls short of expectations, partly due to a mismatch in
parameter configuration.

I also noticed that ice/idpf/ena and other NICs have customized
profilelist or placed some restrictions on dim capabilities.

Motivated by this, I tried adding new params for "ethtool -C" that provides
a per-device control to modify and access a device's interrupt parameters.

Usage
========
The target NIC is named ethx.

Assume that ethx only declares support for rx profile setting
(with DIM_PROFILE_RX flag set in profile_flags) and supports modification
of usec and pkt fields.

1. Query the currently customized list of the device

$ ethtool -c ethx
...
rx-profile:
{.usec =   1, .pkts = 256, .comps = n/a,},
{.usec =   8, .pkts = 256, .comps = n/a,},
{.usec =  64, .pkts = 256, .comps = n/a,},
{.usec = 128, .pkts = 256, .comps = n/a,},
{.usec = 256, .pkts = 256, .comps = n/a,}
tx-profile:   n/a

2. Tune
$ ethtool -C ethx rx-profile 1,1,n_2,n,n_3,3,n_4,4,n_n,5,n
"n" means do not modify this field.
$ ethtool -c ethx
...
rx-profile:
{.usec =   1, .pkts =   1, .comps = n/a,},
{.usec =   2, .pkts = 256, .comps = n/a,},
{.usec =   3, .pkts =   3, .comps = n/a,},
{.usec =   4, .pkts =   4, .comps = n/a,},
{.usec = 256, .pkts =   5, .comps = n/a,}
tx-profile:   n/a

3. Hint
If the device does not support some type of customized dim profiles,
the corresponding "n/a" will display.

If the "n/a" field is being modified, -EOPNOTSUPP will be reported.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 Documentation/netlink/specs/ethtool.yaml     |  31 +++
 Documentation/networking/ethtool-netlink.rst |   4 +
 Documentation/networking/net_dim.rst         |  42 +++
 include/linux/dim.h                          |  58 ++++
 include/linux/ethtool.h                      |   4 +-
 include/linux/netdevice.h                    |   3 +
 include/uapi/linux/ethtool_netlink.h         |  22 ++
 lib/dim/net_dim.c                            |  70 +++++
 net/Kconfig                                  |   1 +
 net/ethtool/coalesce.c                       | 263 ++++++++++++++++++-
 10 files changed, 495 insertions(+), 3 deletions(-)

diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 00dc61358be8..6c2ab3d1c22f 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -414,6 +414,26 @@ attribute-sets:
         name: combined-count
         type: u32
 
+  -
+    name: irq-moderation
+    attributes:
+      -
+        name: usec
+        type: u32
+      -
+        name: pkts
+        type: u32
+      -
+        name: comps
+        type: u32
+  -
+    name: profile
+    attributes:
+      -
+        name: irq-moderation
+        type: nest
+        multi-attr: true
+        nested-attributes: irq-moderation
   -
     name: coalesce
     attributes:
@@ -502,6 +522,15 @@ attribute-sets:
       -
         name: tx-aggr-time-usecs
         type: u32
+      -
+        name: rx-profile
+        type: nest
+        nested-attributes: profile
+      -
+        name: tx-profile
+        type: nest
+        nested-attributes: profile
+
   -
     name: pause-stat
     attributes:
@@ -1325,6 +1354,8 @@ operations:
             - tx-aggr-max-bytes
             - tx-aggr-max-frames
             - tx-aggr-time-usecs
+            - rx-profile
+            - tx-profile
       dump: *coalesce-get-op
     -
       name: coalesce-set
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 160bfb0ae8ba..8b5c82ca8285 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -1033,6 +1033,8 @@ Kernel response contents:
   ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES``     u32     max aggr size, Tx
   ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES``    u32     max aggr packets, Tx
   ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS``    u32     time (us), aggr, Tx
+  ``ETHTOOL_A_COALESCE_RX_PROFILE``            nested  profile of DIM, Rx
+  ``ETHTOOL_A_COALESCE_TX_PROFILE``            nested  profile of DIM, Tx
   ===========================================  ======  =======================
 
 Attributes are only included in reply if their value is not zero or the
@@ -1098,6 +1100,8 @@ Request contents:
   ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES``     u32     max aggr size, Tx
   ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES``    u32     max aggr packets, Tx
   ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS``    u32     time (us), aggr, Tx
+  ``ETHTOOL_A_COALESCE_RX_PROFILE``            nested  profile of DIM, Rx
+  ``ETHTOOL_A_COALESCE_TX_PROFILE``            nested  profile of DIM, Tx
   ===========================================  ======  =======================
 
 Request is rejected if it attributes declared as unsupported by driver (i.e.
diff --git a/Documentation/networking/net_dim.rst b/Documentation/networking/net_dim.rst
index 3bed9fd95336..8908fd7b0a8d 100644
--- a/Documentation/networking/net_dim.rst
+++ b/Documentation/networking/net_dim.rst
@@ -169,6 +169,48 @@ usage is not complete but it should make the outline of the usage clear.
 	...
   }
 
+
+Tuning DIM
+==========
+
+Net DIM serves a range of network devices and delivers excellent acceleration
+benefits. Yet, it has been observed that some preset configurations of DIM may
+not align seamlessly with the varying specifications of network devices, and
+this discrepancy has been identified as a factor to the suboptimal performance
+outcomes of DIM-enabled network devices, related to a mismatch in profiles.
+
+To address this issue, Net DIM introduces a per-device control to modify and
+access a device's ``rx-profile`` and ``tx-profile`` parameters:
+Assume that the target network device is named ethx, and ethx only declares
+support for RX profile setting and supports modification of ``usec`` field
+and ``pkts`` field (See the data structure:
+:c:type:`struct dim_cq_moder <dim_cq_moder>`).
+
+You can use ethtool to modify the current RX DIM profile where all
+values are 64::
+
+    $ ethtool -C ethx rx-profile 1,1,n_2,2,n_3,n,n_n,4,n_n,n,n
+
+``n`` means do not modify this field, and ``_`` separates structure
+elements of the profile array.
+
+Querying the current profiles using::
+
+    $ ethtool -c ethx
+    ...
+    rx-profile:
+    {.usec =   1, .pkts =   1, .comps = n/a,},
+    {.usec =   2, .pkts =   2, .comps = n/a,},
+    {.usec =   3, .pkts =  64, .comps = n/a,},
+    {.usec =  64, .pkts =   4, .comps = n/a,},
+    {.usec =  64, .pkts =  64, .comps = n/a,}
+    tx-profile:   n/a
+
+If the network device does not support specific fields of DIM profiles,
+the corresponding ``n/a`` will display. If the ``n/a`` field is being
+modified, error messages will be reported.
+
+
 Dynamic Interrupt Moderation (DIM) library API
 ==============================================
 
diff --git a/include/linux/dim.h b/include/linux/dim.h
index 43398f5eade2..e0f39bd85432 100644
--- a/include/linux/dim.h
+++ b/include/linux/dim.h
@@ -10,6 +10,8 @@
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
+struct net_device;
+
 /* Number of DIM profiles and period mode. */
 #define NET_DIM_PARAMS_NUM_PROFILES 5
 #define NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE 256
@@ -45,12 +47,45 @@
  * @pkts: CQ packet counter suggestion (by DIM)
  * @comps: Completion counter
  * @cq_period_mode: CQ period count mode (from CQE/EQE)
+ * @rcu: for asynchronous kfree_rcu
  */
 struct dim_cq_moder {
 	u16 usec;
 	u16 pkts;
 	u16 comps;
 	u8 cq_period_mode;
+	struct rcu_head rcu;
+};
+
+#define DIM_PROFILE_RX		BIT(0)	/* support rx profile modification */
+#define DIM_PROFILE_TX		BIT(1)	/* support tx profile modification */
+
+#define DIM_COALESCE_USEC	BIT(0)	/* support usec field modification */
+#define DIM_COALESCE_PKTS	BIT(1)	/* support pkts field modification */
+#define DIM_COALESCE_COMPS	BIT(2)	/* support comps field modification */
+
+/**
+ * struct dim_irq_moder - Structure for irq moderation information.
+ * Used to collect irq moderation related information.
+ *
+ * @profile_flags: DIM_PROFILE_*
+ * @coal_flags: DIM_COALESCE_* for Rx and Tx
+ * @dim_rx_mode: Rx DIM period count mode: CQE or EQE
+ * @dim_tx_mode: Tx DIM period count mode: CQE or EQE
+ * @rx_profile: DIM profile list for Rx
+ * @tx_profile: DIM profile list for Tx
+ * @rx_dim_work: Rx DIM worker scheduled by net_dim()
+ * @tx_dim_work: Tx DIM worker scheduled by net_dim()
+ */
+struct dim_irq_moder {
+	u8 profile_flags;
+	u8 coal_flags;
+	u8 dim_rx_mode;
+	u8 dim_tx_mode;
+	struct dim_cq_moder __rcu *rx_profile;
+	struct dim_cq_moder __rcu *tx_profile;
+	void (*rx_dim_work)(struct work_struct *work);
+	void (*tx_dim_work)(struct work_struct *work);
 };
 
 /**
@@ -198,6 +233,29 @@ enum dim_step_result {
 	DIM_ON_EDGE,
 };
 
+/**
+ * net_dim_init_irq_moder - collect information to initialize irq moderation
+ * @dev: target network device
+ * @profile_flags: Rx or Tx profile modification capability
+ * @coal_flags: irq moderation params flags
+ * @rx_mode: CQ period mode for Rx
+ * @tx_mode: CQ period mode for Tx
+ * @rx_dim_work: Rx worker called after dim decision
+ * @tx_dim_work: Tx worker called after dim decision
+ *
+ * Return: 0 on success or a negative error code.
+ */
+int net_dim_init_irq_moder(struct net_device *dev, u8 profile_flags,
+			   u8 coal_flags, u8 rx_mode, u8 tx_mode,
+			   void (*rx_dim_work)(struct work_struct *work),
+			   void (*tx_dim_work)(struct work_struct *work));
+
+/**
+ * net_dim_free_irq_moder - free fields for irq moderation
+ * @dev: target network device
+ */
+void net_dim_free_irq_moder(struct net_device *dev);
+
 /**
  *	dim_on_top - check if current state is a good place to stop (top location)
  *	@dim: DIM context
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 6fd9107d3cc0..959196af7f5a 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -284,7 +284,9 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
 #define ETHTOOL_COALESCE_TX_AGGR_MAX_BYTES	BIT(24)
 #define ETHTOOL_COALESCE_TX_AGGR_MAX_FRAMES	BIT(25)
 #define ETHTOOL_COALESCE_TX_AGGR_TIME_USECS	BIT(26)
-#define ETHTOOL_COALESCE_ALL_PARAMS		GENMASK(26, 0)
+#define ETHTOOL_COALESCE_RX_PROFILE		BIT(27)
+#define ETHTOOL_COALESCE_TX_PROFILE		BIT(28)
+#define ETHTOOL_COALESCE_ALL_PARAMS		GENMASK(28, 0)
 
 #define ETHTOOL_COALESCE_USECS						\
 	(ETHTOOL_COALESCE_RX_USECS | ETHTOOL_COALESCE_TX_USECS)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d20c6c99eb88..a0d2a0c6b70e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2401,6 +2401,9 @@ struct net_device {
 	/** @page_pools: page pools created for this netdevice */
 	struct hlist_head	page_pools;
 #endif
+
+	/** @irq_moder: dim parameters used if IS_ENABLED(CONFIG_DIMLIB). */
+	struct dim_irq_moder	*irq_moder;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index b49b804b9495..d15856c7e001 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -415,12 +415,34 @@ enum {
 	ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES,		/* u32 */
 	ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES,		/* u32 */
 	ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS,		/* u32 */
+	/* nest - _A_PROFILE_IRQ_MODERATION */
+	ETHTOOL_A_COALESCE_RX_PROFILE,
+	/* nest - _A_PROFILE_IRQ_MODERATION */
+	ETHTOOL_A_COALESCE_TX_PROFILE,
 
 	/* add new constants above here */
 	__ETHTOOL_A_COALESCE_CNT,
 	ETHTOOL_A_COALESCE_MAX = (__ETHTOOL_A_COALESCE_CNT - 1)
 };
 
+enum {
+	ETHTOOL_A_PROFILE_UNSPEC,
+	/* nest, _A_IRQ_MODERATION_* */
+	ETHTOOL_A_PROFILE_IRQ_MODERATION,
+	__ETHTOOL_A_PROFILE_CNT,
+	ETHTOOL_A_PROFILE_MAX = (__ETHTOOL_A_PROFILE_CNT - 1)
+};
+
+enum {
+	ETHTOOL_A_IRQ_MODERATION_UNSPEC,
+	ETHTOOL_A_IRQ_MODERATION_USEC,			/* u32 */
+	ETHTOOL_A_IRQ_MODERATION_PKTS,			/* u32 */
+	ETHTOOL_A_IRQ_MODERATION_COMPS,			/* u32 */
+
+	__ETHTOOL_A_IRQ_MODERATION_CNT,
+	ETHTOOL_A_IRQ_MODERATION_MAX = (__ETHTOOL_A_IRQ_MODERATION_CNT - 1)
+};
+
 /* PAUSE */
 
 enum {
diff --git a/lib/dim/net_dim.c b/lib/dim/net_dim.c
index 67d5beb34dc3..0cd41277c7a3 100644
--- a/lib/dim/net_dim.c
+++ b/lib/dim/net_dim.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/dim.h>
+#include <linux/rtnetlink.h>
 
 /*
  * Net DIM profiles:
@@ -95,6 +96,75 @@ net_dim_get_def_tx_moderation(u8 cq_period_mode)
 }
 EXPORT_SYMBOL(net_dim_get_def_tx_moderation);
 
+int net_dim_init_irq_moder(struct net_device *dev, u8 profile_flags,
+			   u8 coal_flags, u8 rx_mode, u8 tx_mode,
+			   void (*rx_dim_work)(struct work_struct *work),
+			   void (*tx_dim_work)(struct work_struct *work))
+{
+	struct dim_cq_moder *rxp = NULL, *txp;
+	struct dim_irq_moder *moder;
+	int len;
+
+	dev->irq_moder = kzalloc(sizeof(*dev->irq_moder), GFP_KERNEL);
+	if (!dev->irq_moder)
+		return -ENOMEM;
+
+	moder = dev->irq_moder;
+	len = NET_DIM_PARAMS_NUM_PROFILES * sizeof(*moder->rx_profile);
+
+	moder->coal_flags = coal_flags;
+	moder->profile_flags = profile_flags;
+
+	if (profile_flags & DIM_PROFILE_RX) {
+		moder->rx_dim_work = rx_dim_work;
+		moder->dim_rx_mode = rx_mode;
+		rxp = kmemdup(rx_profile[rx_mode], len, GFP_KERNEL);
+		if (!rxp)
+			goto free_moder;
+
+		rcu_assign_pointer(moder->rx_profile, rxp);
+	}
+
+	if (profile_flags & DIM_PROFILE_TX) {
+		moder->tx_dim_work = tx_dim_work;
+		moder->dim_tx_mode = tx_mode;
+		txp = kmemdup(tx_profile[tx_mode], len, GFP_KERNEL);
+		if (!txp)
+			goto free_rxp;
+
+		rcu_assign_pointer(moder->tx_profile, txp);
+	}
+
+	return 0;
+
+free_rxp:
+	kfree(rxp);
+free_moder:
+	kfree(moder);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(net_dim_init_irq_moder);
+
+/* RTNL lock is held. */
+void net_dim_free_irq_moder(struct net_device *dev)
+{
+	struct dim_cq_moder *rxp, *txp;
+
+	if (!dev->irq_moder)
+		return;
+
+	rxp = rtnl_dereference(dev->irq_moder->rx_profile);
+	txp = rtnl_dereference(dev->irq_moder->tx_profile);
+
+	rcu_assign_pointer(dev->irq_moder->rx_profile, NULL);
+	rcu_assign_pointer(dev->irq_moder->tx_profile, NULL);
+
+	kfree_rcu(rxp, rcu);
+	kfree_rcu(txp, rcu);
+	kfree(dev->irq_moder);
+}
+EXPORT_SYMBOL(net_dim_free_irq_moder);
+
 static int net_dim_step(struct dim *dim)
 {
 	if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
diff --git a/net/Kconfig b/net/Kconfig
index f0a8692496ff..e5e66ba3fdad 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -502,6 +502,7 @@ config FAILOVER
 
 config ETHTOOL_NETLINK
 	bool "Netlink interface for ethtool"
+	select DIMLIB
 	default y
 	help
 	  An alternative userspace interface for ethtool based on generic
diff --git a/net/ethtool/coalesce.c b/net/ethtool/coalesce.c
index 83112c1a71ae..1cfd9f6fdcd4 100644
--- a/net/ethtool/coalesce.c
+++ b/net/ethtool/coalesce.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
+#include <linux/dim.h>
 #include "netlink.h"
 #include "common.h"
 
@@ -82,6 +83,14 @@ static int coalesce_prepare_data(const struct ethnl_req_info *req_base,
 static int coalesce_reply_size(const struct ethnl_req_info *req_base,
 			       const struct ethnl_reply_data *reply_base)
 {
+	int modersz = nla_total_size(0) + /* _PROFILE_IRQ_MODERATION, nest */
+		      nla_total_size(sizeof(u32)) + /* _IRQ_MODERATION_USEC */
+		      nla_total_size(sizeof(u32)) + /* _IRQ_MODERATION_PKTS */
+		      nla_total_size(sizeof(u32));  /* _IRQ_MODERATION_COMPS */
+
+	int total_modersz = nla_total_size(0) +  /* _{R,T}X_PROFILE, nest */
+			modersz * NET_DIM_PARAMS_NUM_PROFILES;
+
 	return nla_total_size(sizeof(u32)) +	/* _RX_USECS */
 	       nla_total_size(sizeof(u32)) +	/* _RX_MAX_FRAMES */
 	       nla_total_size(sizeof(u32)) +	/* _RX_USECS_IRQ */
@@ -108,7 +117,8 @@ static int coalesce_reply_size(const struct ethnl_req_info *req_base,
 	       nla_total_size(sizeof(u8)) +	/* _USE_CQE_MODE_RX */
 	       nla_total_size(sizeof(u32)) +	/* _TX_AGGR_MAX_BYTES */
 	       nla_total_size(sizeof(u32)) +	/* _TX_AGGR_MAX_FRAMES */
-	       nla_total_size(sizeof(u32));	/* _TX_AGGR_TIME_USECS */
+	       nla_total_size(sizeof(u32)) +	/* _TX_AGGR_TIME_USECS */
+	       total_modersz * 2;		/* _{R,T}X_PROFILE */
 }
 
 static bool coalesce_put_u32(struct sk_buff *skb, u16 attr_type, u32 val,
@@ -127,14 +137,84 @@ static bool coalesce_put_bool(struct sk_buff *skb, u16 attr_type, u32 val,
 	return nla_put_u8(skb, attr_type, !!val);
 }
 
+/**
+ * coalesce_put_profile - fill reply with a nla nest with four child nla nests.
+ * @skb: socket buffer the message is stored in
+ * @attr_type: nest attr type ETHTOOL_A_COALESCE_*X_PROFILE
+ * @profile: data passed to userspace
+ * @coal_flags: modifiable parameters supported by the driver
+ *
+ * Put a dim profile nest attribute. Refer to ETHTOOL_A_PROFILE_IRQ_MODERATION.
+ *
+ * Return: 0 on success or a negative error code.
+ */
+static int coalesce_put_profile(struct sk_buff *skb, u16 attr_type,
+				const struct dim_cq_moder *profile,
+				u8 coal_flags)
+{
+	struct nlattr *profile_attr, *moder_attr;
+	int i, ret;
+
+	if (!profile || !coal_flags)
+		return 0;
+
+	profile_attr = nla_nest_start(skb, attr_type);
+	if (!profile_attr)
+		return -EMSGSIZE;
+
+	for (i = 0; i < NET_DIM_PARAMS_NUM_PROFILES; i++) {
+		moder_attr = nla_nest_start(skb,
+					    ETHTOOL_A_PROFILE_IRQ_MODERATION);
+		if (!moder_attr) {
+			ret = -EMSGSIZE;
+			goto cancel_profile;
+		}
+
+		if (coal_flags & DIM_COALESCE_USEC) {
+			ret = nla_put_u32(skb, ETHTOOL_A_IRQ_MODERATION_USEC,
+					  profile[i].usec);
+			if (ret)
+				goto cancel_moder;
+		}
+
+		if (coal_flags & DIM_COALESCE_PKTS) {
+			ret = nla_put_u32(skb, ETHTOOL_A_IRQ_MODERATION_PKTS,
+					  profile[i].pkts);
+			if (ret)
+				goto cancel_moder;
+		}
+
+		if (coal_flags & DIM_COALESCE_COMPS) {
+			ret = nla_put_u32(skb, ETHTOOL_A_IRQ_MODERATION_COMPS,
+					  profile[i].comps);
+			if (ret)
+				goto cancel_moder;
+		}
+
+		nla_nest_end(skb, moder_attr);
+	}
+
+	nla_nest_end(skb, profile_attr);
+
+	return 0;
+
+cancel_moder:
+	nla_nest_cancel(skb, moder_attr);
+cancel_profile:
+	nla_nest_cancel(skb, profile_attr);
+	return ret;
+}
+
 static int coalesce_fill_reply(struct sk_buff *skb,
 			       const struct ethnl_req_info *req_base,
 			       const struct ethnl_reply_data *reply_base)
 {
 	const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base);
 	const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce;
+	struct dim_irq_moder *moder = req_base->dev->irq_moder;
 	const struct ethtool_coalesce *coal = &data->coalesce;
 	u32 supported = data->supported_params;
+	int ret = 0;
 
 	if (coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RX_USECS,
 			     coal->rx_coalesce_usecs, supported) ||
@@ -192,11 +272,41 @@ static int coalesce_fill_reply(struct sk_buff *skb,
 			     kcoal->tx_aggr_time_usecs, supported))
 		return -EMSGSIZE;
 
-	return 0;
+	if (!moder)
+		return 0;
+
+	rcu_read_lock();
+	if (moder->profile_flags & DIM_PROFILE_RX) {
+		ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_RX_PROFILE,
+					   rcu_dereference(moder->rx_profile),
+					   moder->coal_flags);
+		if (ret)
+			goto out;
+	}
+
+	if (moder->profile_flags & DIM_PROFILE_TX)
+		ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_TX_PROFILE,
+					   rcu_dereference(moder->tx_profile),
+					   moder->coal_flags);
+
+out:
+	rcu_read_unlock();
+	return ret;
 }
 
 /* COALESCE_SET */
 
+static const struct nla_policy coalesce_irq_moderation_policy[] = {
+	[ETHTOOL_A_IRQ_MODERATION_USEC]	= { .type = NLA_U32 },
+	[ETHTOOL_A_IRQ_MODERATION_PKTS]	= { .type = NLA_U32 },
+	[ETHTOOL_A_IRQ_MODERATION_COMPS] = { .type = NLA_U32 },
+};
+
+static const struct nla_policy coalesce_profile_policy[] = {
+	[ETHTOOL_A_PROFILE_IRQ_MODERATION] =
+		NLA_POLICY_NESTED(coalesce_irq_moderation_policy),
+};
+
 const struct nla_policy ethnl_coalesce_set_policy[] = {
 	[ETHTOOL_A_COALESCE_HEADER]		=
 		NLA_POLICY_NESTED(ethnl_header_policy),
@@ -227,6 +337,10 @@ const struct nla_policy ethnl_coalesce_set_policy[] = {
 	[ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES] = { .type = NLA_U32 },
 	[ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES] = { .type = NLA_U32 },
 	[ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS] = { .type = NLA_U32 },
+	[ETHTOOL_A_COALESCE_RX_PROFILE] =
+		NLA_POLICY_NESTED(coalesce_profile_policy),
+	[ETHTOOL_A_COALESCE_TX_PROFILE] =
+		NLA_POLICY_NESTED(coalesce_profile_policy),
 };
 
 static int
@@ -234,6 +348,7 @@ ethnl_set_coalesce_validate(struct ethnl_req_info *req_info,
 			    struct genl_info *info)
 {
 	const struct ethtool_ops *ops = req_info->dev->ethtool_ops;
+	struct dim_irq_moder *irq_moder = req_info->dev->irq_moder;
 	struct nlattr **tb = info->attrs;
 	u32 supported_params;
 	u16 a;
@@ -243,6 +358,12 @@ ethnl_set_coalesce_validate(struct ethnl_req_info *req_info,
 
 	/* make sure that only supported parameters are present */
 	supported_params = ops->supported_coalesce_params;
+	if (irq_moder && irq_moder->profile_flags & DIM_PROFILE_RX)
+		supported_params |= ETHTOOL_COALESCE_RX_PROFILE;
+
+	if (irq_moder && irq_moder->profile_flags & DIM_PROFILE_TX)
+		supported_params |= ETHTOOL_COALESCE_TX_PROFILE;
+
 	for (a = ETHTOOL_A_COALESCE_RX_USECS; a < __ETHTOOL_A_COALESCE_CNT; a++)
 		if (tb[a] && !(supported_params & attr_to_mask(a))) {
 			NL_SET_ERR_MSG_ATTR(info->extack, tb[a],
@@ -253,6 +374,128 @@ ethnl_set_coalesce_validate(struct ethnl_req_info *req_info,
 	return 1;
 }
 
+/**
+ * ethnl_update_irq_moder - update a specific field in the given profile
+ * @irq_moder: place that collects dim related information
+ * @irq_field: field in profile to modify
+ * @attr_type: attr type ETHTOOL_A_IRQ_MODERATION_*
+ * @tb: netlink attribute with new values or null
+ * @coal_bit: DIM_COALESCE_* bit from coal_flags
+ * @extack: netlink extended ack
+ *
+ * Return: 0 on success or a negative error code.
+ */
+static int ethnl_update_irq_moder(struct dim_irq_moder *irq_moder,
+				  u16 *irq_field, u16 attr_type,
+				  struct nlattr **tb, u8 coal_bit,
+				  struct netlink_ext_ack *extack)
+{
+	int ret = 0;
+
+	if (!tb[attr_type])
+		return 0;
+
+	if (irq_moder->coal_flags & coal_bit) {
+		*irq_field = nla_get_u32(tb[attr_type]);
+	} else {
+		NL_SET_BAD_ATTR(extack, tb[attr_type]);
+		ret = -EOPNOTSUPP;
+	}
+
+	return ret;
+}
+
+/**
+ * ethnl_update_profile - get a profile nest with child nests from userspace.
+ * @dev: netdevice to update the profile
+ * @dst: profile get from the driver and modified by ethnl_update_profile.
+ * @nests: nest attr ETHTOOL_A_COALESCE_*X_PROFILE to set profile.
+ * @extack: Netlink extended ack
+ *
+ * Layout of nests:
+ *   Nested ETHTOOL_A_COALESCE_*X_PROFILE attr
+ *     Nested ETHTOOL_A_PROFILE_IRQ_MODERATION attr
+ *       ETHTOOL_A_IRQ_MODERATION_USEC attr
+ *       ETHTOOL_A_IRQ_MODERATION_PKTS attr
+ *       ETHTOOL_A_IRQ_MODERATION_COMPS attr
+ *     ...
+ *     Nested ETHTOOL_A_PROFILE_IRQ_MODERATION attr
+ *       ETHTOOL_A_IRQ_MODERATION_USEC attr
+ *       ETHTOOL_A_IRQ_MODERATION_PKTS attr
+ *       ETHTOOL_A_IRQ_MODERATION_COMPS attr
+ *
+ * Return: 0 on success or a negative error code.
+ */
+static int ethnl_update_profile(struct net_device *dev,
+				struct dim_cq_moder __rcu **dst,
+				const struct nlattr *nests,
+				struct netlink_ext_ack *extack)
+{
+	int len_irq_moder = ARRAY_SIZE(coalesce_irq_moderation_policy);
+	struct nlattr *tb[ARRAY_SIZE(coalesce_irq_moderation_policy)];
+	struct dim_irq_moder *irq_moder = dev->irq_moder;
+	struct dim_cq_moder *new_profile, *old_profile;
+	int ret, rem, i = 0, len;
+	struct nlattr *nest;
+
+	if (!nests)
+		return 0;
+
+	if (!*dst)
+		return -EOPNOTSUPP;
+
+	old_profile = rtnl_dereference(*dst);
+	len = NET_DIM_PARAMS_NUM_PROFILES * sizeof(*old_profile);
+	new_profile = kmemdup(old_profile, len, GFP_KERNEL);
+	if (!new_profile)
+		return -ENOMEM;
+
+	nla_for_each_nested_type(nest, ETHTOOL_A_PROFILE_IRQ_MODERATION,
+				 nests, rem) {
+		ret = nla_parse_nested(tb, len_irq_moder - 1, nest,
+				       coalesce_irq_moderation_policy,
+				       extack);
+		if (ret)
+			goto err_out;
+
+		ret = ethnl_update_irq_moder(irq_moder, &new_profile[i].usec,
+					     ETHTOOL_A_IRQ_MODERATION_USEC,
+					     tb, DIM_COALESCE_USEC,
+					     extack);
+		if (ret)
+			goto err_out;
+
+		ret = ethnl_update_irq_moder(irq_moder, &new_profile[i].pkts,
+					     ETHTOOL_A_IRQ_MODERATION_PKTS,
+					     tb, DIM_COALESCE_PKTS,
+					     extack);
+		if (ret)
+			goto err_out;
+
+		ret = ethnl_update_irq_moder(irq_moder, &new_profile[i].comps,
+					     ETHTOOL_A_IRQ_MODERATION_COMPS,
+					     tb, DIM_COALESCE_COMPS,
+					     extack);
+		if (ret)
+			goto err_out;
+
+		i++;
+	}
+
+	/* After the profile is modified, dim itself is a dynamic
+	 * mechanism and will quickly fit to the appropriate
+	 * coalescing parameters according to the new profile.
+	 */
+	rcu_assign_pointer(*dst, new_profile);
+	kfree_rcu(old_profile, rcu);
+
+	return 0;
+
+err_out:
+	kfree(new_profile);
+	return ret;
+}
+
 static int
 __ethnl_set_coalesce(struct ethnl_req_info *req_info, struct genl_info *info,
 		     bool *dual_change)
@@ -317,6 +560,22 @@ __ethnl_set_coalesce(struct ethnl_req_info *req_info, struct genl_info *info,
 	ethnl_update_u32(&kernel_coalesce.tx_aggr_time_usecs,
 			 tb[ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS], &mod);
 
+	if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_RX) {
+		ret = ethnl_update_profile(dev, &dev->irq_moder->rx_profile,
+					   tb[ETHTOOL_A_COALESCE_RX_PROFILE],
+					   info->extack);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_TX) {
+		ret = ethnl_update_profile(dev, &dev->irq_moder->tx_profile,
+					   tb[ETHTOOL_A_COALESCE_TX_PROFILE],
+					   info->extack);
+		if (ret < 0)
+			return ret;
+	}
+
 	/* Update operation modes */
 	ethnl_update_bool32(&coalesce.use_adaptive_rx_coalesce,
 			    tb[ETHTOOL_A_COALESCE_USE_ADAPTIVE_RX], &mod_mode);
-- 
2.32.0.3.g01195cf9f

Re: [PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Simon Horman]

On Tue, Jun 18, 2024 at 10:56:42AM +0800, Heng Qi wrote:
> The NetDIM library, currently leveraged by an array of NICs, delivers
> excellent acceleration benefits. Nevertheless, NICs vary significantly
> in their dim profile list prerequisites.
> 
> Specifically, virtio-net backends may present diverse sw or hw device
> implementation, making a one-size-fits-all parameter list impractical.
> On Alibaba Cloud, the virtio DPU's performance under the default DIM
> profile falls short of expectations, partly due to a mismatch in
> parameter configuration.
> 
> I also noticed that ice/idpf/ena and other NICs have customized
> profilelist or placed some restrictions on dim capabilities.
> 
> Motivated by this, I tried adding new params for "ethtool -C" that provides
> a per-device control to modify and access a device's interrupt parameters.
> 
> Usage
> ========
> The target NIC is named ethx.
> 
> Assume that ethx only declares support for rx profile setting
> (with DIM_PROFILE_RX flag set in profile_flags) and supports modification
> of usec and pkt fields.
> 
> 1. Query the currently customized list of the device
> 
> $ ethtool -c ethx
> ...
> rx-profile:
> {.usec =   1, .pkts = 256, .comps = n/a,},
> {.usec =   8, .pkts = 256, .comps = n/a,},
> {.usec =  64, .pkts = 256, .comps = n/a,},
> {.usec = 128, .pkts = 256, .comps = n/a,},
> {.usec = 256, .pkts = 256, .comps = n/a,}
> tx-profile:   n/a
> 
> 2. Tune
> $ ethtool -C ethx rx-profile 1,1,n_2,n,n_3,3,n_4,4,n_n,5,n
> "n" means do not modify this field.
> $ ethtool -c ethx
> ...
> rx-profile:
> {.usec =   1, .pkts =   1, .comps = n/a,},
> {.usec =   2, .pkts = 256, .comps = n/a,},
> {.usec =   3, .pkts =   3, .comps = n/a,},
> {.usec =   4, .pkts =   4, .comps = n/a,},
> {.usec = 256, .pkts =   5, .comps = n/a,}
> tx-profile:   n/a
> 
> 3. Hint
> If the device does not support some type of customized dim profiles,
> the corresponding "n/a" will display.
> 
> If the "n/a" field is being modified, -EOPNOTSUPP will be reported.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Jakub Kicinski]

On Tue, 18 Jun 2024 10:56:42 +0800 Heng Qi wrote:
> +	if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_RX) {
> +		ret = ethnl_update_profile(dev, &dev->irq_moder->rx_profile,
> +					   tb[ETHTOOL_A_COALESCE_RX_PROFILE],
> +					   info->extack);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_TX) {
> +		ret = ethnl_update_profile(dev, &dev->irq_moder->tx_profile,
> +					   tb[ETHTOOL_A_COALESCE_TX_PROFILE],
> +					   info->extack);
> +		if (ret < 0)
> +			return ret;
> +	}

One last thing - you're missing updating the &mod bit.
When any of the settings were change mod should be set
to true so that we send a notification to user space,
that the settings have been modified.

Re: [PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Heng Qi]

On Thu, 20 Jun 2024 20:39:18 -0700, Jakub Kicinski <kuba@kernel.org> wrote:
> On Tue, 18 Jun 2024 10:56:42 +0800 Heng Qi wrote:
> > +	if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_RX) {
> > +		ret = ethnl_update_profile(dev, &dev->irq_moder->rx_profile,
> > +					   tb[ETHTOOL_A_COALESCE_RX_PROFILE],
> > +					   info->extack);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_TX) {
> > +		ret = ethnl_update_profile(dev, &dev->irq_moder->tx_profile,
> > +					   tb[ETHTOOL_A_COALESCE_TX_PROFILE],
> > +					   info->extack);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> 
> One last thing - you're missing updating the &mod bit.
> When any of the settings were change mod should be set
> to true so that we send a notification to user space,
> that the settings have been modified.

Oh, I didn't modify the mod bit in the past because the profile list
modification does not require the dual_change behavior, ignoring the
passing of ret = 0/1. Will modify.

Thanks.

Re: [PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Jakub Kicinski]

On Tue, 18 Jun 2024 10:56:42 +0800 Heng Qi wrote:
> --- a/Documentation/networking/ethtool-netlink.rst
> +++ b/Documentation/networking/ethtool-netlink.rst
> @@ -1033,6 +1033,8 @@ Kernel response contents:
>    ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES``     u32     max aggr size, Tx
>    ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES``    u32     max aggr packets, Tx
>    ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS``    u32     time (us), aggr, Tx
> +  ``ETHTOOL_A_COALESCE_RX_PROFILE``            nested  profile of DIM, Rx
> +  ``ETHTOOL_A_COALESCE_TX_PROFILE``            nested  profile of DIM, Tx
>    ===========================================  ======  =======================
>  
>  Attributes are only included in reply if their value is not zero or the

Maybe add a short line in the section for COALESCE_GET linking to dim?
Something like:

``ETHTOOL_A_COALESCE_RX_PROFILE`` and ``ETHTOOL_A_COALESCE_TX_PROFILE``
refer to DIM parameters, see ... <- add ReST link to net_dim.rst here.

Re: [PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Heng Qi]

On Thu, 20 Jun 2024 20:44:45 -0700, Jakub Kicinski <kuba@kernel.org> wrote:
> On Tue, 18 Jun 2024 10:56:42 +0800 Heng Qi wrote:
> > --- a/Documentation/networking/ethtool-netlink.rst
> > +++ b/Documentation/networking/ethtool-netlink.rst
> > @@ -1033,6 +1033,8 @@ Kernel response contents:
> >    ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES``     u32     max aggr size, Tx
> >    ``ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES``    u32     max aggr packets, Tx
> >    ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS``    u32     time (us), aggr, Tx
> > +  ``ETHTOOL_A_COALESCE_RX_PROFILE``            nested  profile of DIM, Rx
> > +  ``ETHTOOL_A_COALESCE_TX_PROFILE``            nested  profile of DIM, Tx
> >    ===========================================  ======  =======================
> >  
> >  Attributes are only included in reply if their value is not zero or the
> 
> Maybe add a short line in the section for COALESCE_GET linking to dim?
> Something like:
> 
> ``ETHTOOL_A_COALESCE_RX_PROFILE`` and ``ETHTOOL_A_COALESCE_TX_PROFILE``
> refer to DIM parameters, see ... <- add ReST link to net_dim.rst here.

Will add.

Thanks.

[PATCH RESEND net-next v14 4/5] dim: add new interfaces for initialization and getting results

[Heng Qi]

DIM-related mode and work have been collected in one same place,
so new interfaces are added to provide convenience.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 include/linux/dim.h | 48 ++++++++++++++++++++++++++++++++
 lib/dim/net_dim.c   | 68 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+)

diff --git a/include/linux/dim.h b/include/linux/dim.h
index e0f39bd85432..1b581ff25a15 100644
--- a/include/linux/dim.h
+++ b/include/linux/dim.h
@@ -256,6 +256,54 @@ int net_dim_init_irq_moder(struct net_device *dev, u8 profile_flags,
  */
 void net_dim_free_irq_moder(struct net_device *dev);
 
+/**
+ * net_dim_setting - initialize DIM's cq mode and schedule worker
+ * @dev: target network device
+ * @dim: DIM context
+ * @is_tx: true indicates the tx direction, false indicates the rx direction
+ */
+void net_dim_setting(struct net_device *dev, struct dim *dim, bool is_tx);
+
+/**
+ * net_dim_work_cancel - synchronously cancel dim's worker
+ * @dim: DIM context
+ */
+void net_dim_work_cancel(struct dim *dim);
+
+/**
+ * net_dim_get_rx_irq_moder - get DIM rx results based on profile_ix
+ * @dev: target network device
+ * @dim: DIM context
+ *
+ * Return: DIM irq moderation
+ */
+struct dim_cq_moder
+net_dim_get_rx_irq_moder(struct net_device *dev, struct dim *dim);
+
+/**
+ * net_dim_get_tx_irq_moder - get DIM tx results based on profile_ix
+ * @dev: target network device
+ * @dim: DIM context
+ *
+ * Return: DIM irq moderation
+ */
+struct dim_cq_moder
+net_dim_get_tx_irq_moder(struct net_device *dev, struct dim *dim);
+
+/**
+ * net_dim_set_rx_mode - set DIM rx cq mode
+ * @dev: target network device
+ * @rx_mode: target rx cq mode
+ */
+void net_dim_set_rx_mode(struct net_device *dev, u8 rx_mode);
+
+/**
+ * net_dim_set_tx_mode - set DIM tx cq mode
+ * @dev: target network device
+ * @tx_mode: target tx cq mode
+ */
+void net_dim_set_tx_mode(struct net_device *dev, u8 tx_mode);
+
 /**
  *	dim_on_top - check if current state is a good place to stop (top location)
  *	@dim: DIM context
diff --git a/lib/dim/net_dim.c b/lib/dim/net_dim.c
index 0cd41277c7a3..d7e7028e9b19 100644
--- a/lib/dim/net_dim.c
+++ b/lib/dim/net_dim.c
@@ -165,6 +165,74 @@ void net_dim_free_irq_moder(struct net_device *dev)
 }
 EXPORT_SYMBOL(net_dim_free_irq_moder);
 
+void net_dim_setting(struct net_device *dev, struct dim *dim, bool is_tx)
+{
+	struct dim_irq_moder *irq_moder = dev->irq_moder;
+
+	if (!irq_moder)
+		return;
+
+	if (is_tx) {
+		INIT_WORK(&dim->work, irq_moder->tx_dim_work);
+		dim->mode = READ_ONCE(irq_moder->dim_tx_mode);
+		return;
+	}
+
+	INIT_WORK(&dim->work, irq_moder->rx_dim_work);
+	dim->mode = READ_ONCE(irq_moder->dim_rx_mode);
+}
+EXPORT_SYMBOL(net_dim_setting);
+
+void net_dim_work_cancel(struct dim *dim)
+{
+	cancel_work_sync(&dim->work);
+}
+EXPORT_SYMBOL(net_dim_work_cancel);
+
+struct dim_cq_moder net_dim_get_rx_irq_moder(struct net_device *dev,
+					     struct dim *dim)
+{
+	struct dim_cq_moder res, *profile;
+
+	rcu_read_lock();
+	profile = rcu_dereference(dev->irq_moder->rx_profile);
+	res = profile[dim->profile_ix];
+	rcu_read_unlock();
+
+	res.cq_period_mode = dim->mode;
+
+	return res;
+}
+EXPORT_SYMBOL(net_dim_get_rx_irq_moder);
+
+struct dim_cq_moder net_dim_get_tx_irq_moder(struct net_device *dev,
+					     struct dim *dim)
+{
+	struct dim_cq_moder res, *profile;
+
+	rcu_read_lock();
+	profile = rcu_dereference(dev->irq_moder->tx_profile);
+	res = profile[dim->profile_ix];
+	rcu_read_unlock();
+
+	res.cq_period_mode = dim->mode;
+
+	return res;
+}
+EXPORT_SYMBOL(net_dim_get_tx_irq_moder);
+
+void net_dim_set_rx_mode(struct net_device *dev, u8 rx_mode)
+{
+	WRITE_ONCE(dev->irq_moder->dim_rx_mode, rx_mode);
+}
+EXPORT_SYMBOL(net_dim_set_rx_mode);
+
+void net_dim_set_tx_mode(struct net_device *dev, u8 tx_mode)
+{
+	WRITE_ONCE(dev->irq_moder->dim_tx_mode, tx_mode);
+}
+EXPORT_SYMBOL(net_dim_set_tx_mode);
+
 static int net_dim_step(struct dim *dim)
 {
 	if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
-- 
2.32.0.3.g01195cf9f

Re: [PATCH RESEND net-next v14 4/5] dim: add new interfaces for initialization and getting results

[Simon Horman]

On Tue, Jun 18, 2024 at 10:56:43AM +0800, Heng Qi wrote:
> DIM-related mode and work have been collected in one same place,
> so new interfaces are added to provide convenience.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>

Reviewed-by: Simon Horman <horms@kernel.org>

[PATCH RESEND net-next v14 5/5] virtio-net: support dim profile fine-tuning

[Heng Qi]

Virtio-net has different types of back-end device implementations.
In order to effectively optimize the dim library's gains for different
device implementations, let's use the new interface params to
initialize and query dim results from a customized profile list.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 54 ++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 7 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 4a802c0ea2cb..f9e15099982d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2421,6 +2421,13 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
 	return err;
 }
 
+static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
+{
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
+		return;
+	net_dim_work_cancel(dim);
+}
+
 static int virtnet_open(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -2447,7 +2454,7 @@ static int virtnet_open(struct net_device *dev)
 
 	for (i--; i >= 0; i--) {
 		virtnet_disable_queue_pair(vi, i);
-		cancel_work_sync(&vi->rq[i].dim.work);
+		virtnet_cancel_dim(vi, &vi->rq[i].dim);
 	}
 
 	return err;
@@ -2619,7 +2626,7 @@ static int virtnet_rx_resize(struct virtnet_info *vi,
 
 	if (running) {
 		napi_disable(&rq->napi);
-		cancel_work_sync(&rq->dim.work);
+		virtnet_cancel_dim(vi, &rq->dim);
 	}
 
 	err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_unmap_free_buf);
@@ -2878,7 +2885,7 @@ static int virtnet_close(struct net_device *dev)
 
 	for (i = 0; i < vi->max_queue_pairs; i++) {
 		virtnet_disable_queue_pair(vi, i);
-		cancel_work_sync(&vi->rq[i].dim.work);
+		virtnet_cancel_dim(vi, &vi->rq[i].dim);
 	}
 
 	return 0;
@@ -4408,7 +4415,7 @@ static void virtnet_rx_dim_work(struct work_struct *work)
 	if (!rq->dim_enabled)
 		goto out;
 
-	update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
+	update_moder = net_dim_get_rx_irq_moder(dev, dim);
 	if (update_moder.usec != rq->intr_coal.max_usecs ||
 	    update_moder.pkts != rq->intr_coal.max_packets) {
 		err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
@@ -5108,6 +5115,36 @@ static void virtnet_tx_timeout(struct net_device *dev, unsigned int txqueue)
 		   jiffies_to_usecs(jiffies - READ_ONCE(txq->trans_start)));
 }
 
+static int virtnet_init_irq_moder(struct virtnet_info *vi)
+{
+	u8 profile_flags = 0, coal_flags = 0;
+	int ret, i;
+
+	profile_flags |= DIM_PROFILE_RX;
+	coal_flags |= DIM_COALESCE_USEC | DIM_COALESCE_PKTS;
+	ret = net_dim_init_irq_moder(vi->dev, profile_flags, coal_flags,
+				     DIM_CQ_PERIOD_MODE_START_FROM_EQE,
+				     0, virtnet_rx_dim_work, NULL);
+
+	if (ret)
+		return ret;
+
+	for (i = 0; i < vi->max_queue_pairs; i++)
+		net_dim_setting(vi->dev, &vi->rq[i].dim, false);
+
+	return 0;
+}
+
+static void virtnet_free_irq_moder(struct virtnet_info *vi)
+{
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
+		return;
+
+	rtnl_lock();
+	net_dim_free_irq_moder(vi->dev);
+	rtnl_unlock();
+}
+
 static const struct net_device_ops virtnet_netdev = {
 	.ndo_open            = virtnet_open,
 	.ndo_stop   	     = virtnet_close,
@@ -5387,9 +5424,6 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
 					 virtnet_poll_tx,
 					 napi_tx ? napi_weight : 0);
 
-		INIT_WORK(&vi->rq[i].dim.work, virtnet_rx_dim_work);
-		vi->rq[i].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
-
 		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
 		ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
 		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
@@ -5810,6 +5844,10 @@ static int virtnet_probe(struct virtio_device *vdev)
 		for (i = 0; i < vi->max_queue_pairs; i++)
 			if (vi->sq[i].napi.weight)
 				vi->sq[i].intr_coal.max_packets = 1;
+
+		err = virtnet_init_irq_moder(vi);
+		if (err)
+			goto free;
 	}
 
 #ifdef CONFIG_SYSFS
@@ -5961,6 +5999,8 @@ static void virtnet_remove(struct virtio_device *vdev)
 	disable_rx_mode_work(vi);
 	flush_work(&vi->rx_mode_work);
 
+	virtnet_free_irq_moder(vi);
+
 	unregister_netdev(vi->dev);
 
 	net_failover_destroy(vi->failover);
-- 
2.32.0.3.g01195cf9f

Re: [PATCH RESEND net-next v14 5/5] virtio-net: support dim profile fine-tuning

[Simon Horman]

On Tue, Jun 18, 2024 at 10:56:44AM +0800, Heng Qi wrote:
> Virtio-net has different types of back-end device implementations.
> In order to effectively optimize the dim library's gains for different
> device implementations, let's use the new interface params to
> initialize and query dim results from a customized profile list.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH RESEND net-next v14 0/5] ethtool: provide the dim profile fine-tuning channel

[Jakub Kicinski]

On Tue, 18 Jun 2024 10:56:39 +0800 Heng Qi wrote:
> The NetDIM library provides excellent acceleration for many modern
> network cards. However, the default profiles of DIM limits its maximum
> capabilities for different NICs, so providing a way which the NIC can
> be custom configured is necessary.

Could you give an example in the cover letter of a type of workload and
how much a new set of DIM values helped?

Re: [PATCH RESEND net-next v14 0/5] ethtool: provide the dim profile fine-tuning channel

[Heng Qi]

On Thu, 20 Jun 2024 20:40:25 -0700, Jakub Kicinski <kuba@kernel.org> wrote:
> On Tue, 18 Jun 2024 10:56:39 +0800 Heng Qi wrote:
> > The NetDIM library provides excellent acceleration for many modern
> > network cards. However, the default profiles of DIM limits its maximum
> > capabilities for different NICs, so providing a way which the NIC can
> > be custom configured is necessary.
> 
> Could you give an example in the cover letter of a type of workload and
> how much a new set of DIM values helped?

Sure.