[PATCH net-next v3 3/3] virtio-net: support dim profile fine-tuning

[Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>]

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 fine-tune the profile list.

Signed-off-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
---
 drivers/net/virtio_net.c   | 42 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/virtio_net.h | 11 +++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5c56fdc..732214b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -330,6 +330,12 @@ struct virtnet_info {
 	struct virtnet_interrupt_coalesce intr_coal_tx;
 	struct virtnet_interrupt_coalesce intr_coal_rx;
 
+	/* DIM profile list for different queue mode */
+	struct dim_cq_moder rx_eqe_conf[NET_DIM_PARAMS_NUM_PROFILES];
+	struct dim_cq_moder rx_cqe_conf[NET_DIM_PARAMS_NUM_PROFILES];
+	struct dim_cq_moder tx_eqe_conf[NET_DIM_PARAMS_NUM_PROFILES];
+	struct dim_cq_moder tx_cqe_conf[NET_DIM_PARAMS_NUM_PROFILES];
+
 	unsigned long guest_offloads;
 	unsigned long guest_offloads_capable;
 
@@ -3588,7 +3594,7 @@ static void virtnet_rx_dim_work(struct work_struct *work)
 		if (!rq->dim_enabled)
 			continue;
 
-		update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
+		update_moder = vi->rx_eqe_conf[dim->profile_ix];
 		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,
@@ -3631,6 +3637,27 @@ static int virtnet_should_update_vq_weight(int dev_flags, int weight,
 	return 0;
 }
 
+static int virtnet_update_profile(struct virtnet_info *vi,
+				  struct kernel_ethtool_coalesce *kc)
+{
+	int i;
+
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
+		for (i = 0; i < NET_DIM_PARAMS_NUM_PROFILES; i++)
+			if (kc->rx_eqe_profs[i].comps)
+				return -EINVAL;
+	} else {
+		return -EOPNOTSUPP;
+	}
+
+	for (i = 0; i < NET_DIM_PARAMS_NUM_PROFILES; i++) {
+		vi->rx_eqe_conf[i].usec = kc->rx_eqe_profs[i].usec;
+		vi->rx_eqe_conf[i].pkts = kc->rx_eqe_profs[i].pkts;
+	}
+
+	return 0;
+}
+
 static int virtnet_set_coalesce(struct net_device *dev,
 				struct ethtool_coalesce *ec,
 				struct kernel_ethtool_coalesce *kernel_coal,
@@ -3657,6 +3684,10 @@ static int virtnet_set_coalesce(struct net_device *dev,
 		}
 	}
 
+	ret = virtnet_update_profile(vi, kernel_coal);
+	if (ret)
+		return ret;
+
 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL))
 		ret = virtnet_send_notf_coal_cmds(vi, ec);
 	else
@@ -3693,6 +3724,10 @@ static int virtnet_get_coalesce(struct net_device *dev,
 			ec->tx_max_coalesced_frames = 1;
 	}
 
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
+		memcpy(kernel_coal->rx_eqe_profs, vi->rx_eqe_conf,
+		       sizeof(vi->rx_eqe_conf));
+
 	return 0;
 }
 
@@ -3872,7 +3907,8 @@ static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info)
 
 static const struct ethtool_ops virtnet_ethtool_ops = {
 	.supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |
-		ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
+		ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX |
+		ETHTOOL_COALESCE_RX_EQE_PROFILE,
 	.get_drvinfo = virtnet_get_drvinfo,
 	.get_link = ethtool_op_get_link,
 	.get_ringparam = virtnet_get_ringparam,
@@ -4437,6 +4473,8 @@ static void virtnet_dim_init(struct virtnet_info *vi)
 		INIT_WORK(&vi->rq[i].dim.work, virtnet_rx_dim_work);
 		vi->rq[i].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
 	}
+
+	memcpy(vi->rx_eqe_conf, rx_eqe_conf, sizeof(vi->rx_eqe_conf));
 }
 
 static int virtnet_alloc_queues(struct virtnet_info *vi)
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 4dfa9b6..82aa4cc 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -6,9 +6,20 @@
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/udp.h>
+#include <linux/dim.h>
 #include <uapi/linux/tcp.h>
 #include <uapi/linux/virtio_net.h>
 
+/* This is copied from NET_DIM_RX_EQE_PROFILES in DIM library */
+#define VIRTNET_DIM_RX_PKTS 256
+static const struct dim_cq_moder rx_eqe_conf[] = {
+	{.usec = 1,   .pkts = VIRTNET_DIM_RX_PKTS,},
+	{.usec = 8,   .pkts = VIRTNET_DIM_RX_PKTS,},
+	{.usec = 64,  .pkts = VIRTNET_DIM_RX_PKTS,},
+	{.usec = 128, .pkts = VIRTNET_DIM_RX_PKTS,},
+	{.usec = 256, .pkts = VIRTNET_DIM_RX_PKTS,}
+};
+
 static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type)
 {
 	switch (gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
-- 
1.8.3.1