net/mlx5e: Support adaptive RX coalescing

Striving for high message rate and low interrupt rate.

Usage:
        ethtool -C <interface> adaptive-rx on/off

Signed-off-by: Gil Rockah <gilr@mellanox.com>
Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -7,6 +7,7 @@ mlx5_core-y :=	main.o cmd.o debugfs.o fw.o eq.o uar.o pagealloc.o \
 
 mlx5_core-$(CONFIG_MLX5_CORE_EN) += wq.o eswitch.o \
 		en_main.o en_fs.o en_ethtool.o en_tx.o en_rx.o \
-		en_txrx.o en_clock.o vxlan.o en_tc.o en_arfs.o
+		en_rx_am.o en_txrx.o en_clock.o vxlan.o en_tc.o \
+		en_arfs.o
 
 mlx5_core-$(CONFIG_MLX5_CORE_EN_DCB) +=  en_dcbnl.o

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -195,6 +195,7 @@ struct mlx5e_params {
 #ifdef CONFIG_MLX5_CORE_EN_DCB
 	struct ieee_ets ets;
 #endif
+	bool rx_am_enabled;
 };
 
 struct mlx5e_tstamp {
@@ -213,13 +214,15 @@ struct mlx5e_tstamp {
 enum {
 	MLX5E_RQ_STATE_POST_WQES_ENABLE,
 	MLX5E_RQ_STATE_UMR_WQE_IN_PROGRESS,
+	MLX5E_RQ_STATE_AM,
 };
 
 struct mlx5e_cq {
 	/* data path - accessed per cqe */
 	struct mlx5_cqwq           wq;
 
 	/* data path - accessed per napi poll */
+	u16                        event_ctr;
 	struct napi_struct        *napi;
 	struct mlx5_core_cq        mcq;
 	struct mlx5e_channel      *channel;
@@ -247,6 +250,30 @@ struct mlx5e_dma_info {
 	dma_addr_t	addr;
 };
 
+struct mlx5e_rx_am_stats {
+	int ppms; /* packets per msec */
+	int epms; /* events per msec */
+};
+
+struct mlx5e_rx_am_sample {
+	ktime_t		time;
+	unsigned int	pkt_ctr;
+	u16		event_ctr;
+};
+
+struct mlx5e_rx_am { /* Adaptive Moderation */
+	u8					state;
+	struct mlx5e_rx_am_stats		prev_stats;
+	struct mlx5e_rx_am_sample		start_sample;
+	struct work_struct			work;
+	u8					profile_ix;
+	u8					mode;
+	u8					tune_state;
+	u8					steps_right;
+	u8					steps_left;
+	u8					tired;
+};
+
 struct mlx5e_rq {
 	/* data path */
 	struct mlx5_wq_ll      wq;
@@ -267,6 +294,8 @@ struct mlx5e_rq {
 	unsigned long          state;
 	int                    ix;
 
+	struct mlx5e_rx_am     am; /* Adaptive Moderation */
+
 	/* control */
 	struct mlx5_wq_ctrl    wq_ctrl;
 	u8                     wq_type;
@@ -637,6 +666,10 @@ void mlx5e_free_rx_fragmented_mpwqe(struct mlx5e_rq *rq,
 				    struct mlx5e_mpw_info *wi);
 struct mlx5_cqe64 *mlx5e_get_cqe(struct mlx5e_cq *cq);
 
+void mlx5e_rx_am(struct mlx5e_rq *rq);
+void mlx5e_rx_am_work(struct work_struct *work);
+struct mlx5e_cq_moder mlx5e_am_get_def_profile(u8 rx_cq_period_mode);
+
 void mlx5e_update_stats(struct mlx5e_priv *priv);
 
 int mlx5e_create_flow_steering(struct mlx5e_priv *priv);

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c

@@ -528,6 +528,7 @@ static int mlx5e_get_coalesce(struct net_device *netdev,
 	coal->rx_max_coalesced_frames = priv->params.rx_cq_moderation.pkts;
 	coal->tx_coalesce_usecs       = priv->params.tx_cq_moderation.usec;
 	coal->tx_max_coalesced_frames = priv->params.tx_cq_moderation.pkts;
+	coal->use_adaptive_rx_coalesce = priv->params.rx_am_enabled;
 
 	return 0;
 }
@@ -538,6 +539,10 @@ static int mlx5e_set_coalesce(struct net_device *netdev,
 	struct mlx5e_priv *priv    = netdev_priv(netdev);
 	struct mlx5_core_dev *mdev = priv->mdev;
 	struct mlx5e_channel *c;
+	bool restart =
+		!!coal->use_adaptive_rx_coalesce != priv->params.rx_am_enabled;
+	bool was_opened;
+	int err = 0;
 	int tc;
 	int i;
 
@@ -546,12 +551,18 @@ static int mlx5e_set_coalesce(struct net_device *netdev,
 
 	mutex_lock(&priv->state_lock);
 
+	was_opened = test_bit(MLX5E_STATE_OPENED, &priv->state);
+	if (was_opened && restart) {
+		mlx5e_close_locked(netdev);
+		priv->params.rx_am_enabled = !!coal->use_adaptive_rx_coalesce;
+	}
+
 	priv->params.tx_cq_moderation.usec = coal->tx_coalesce_usecs;
 	priv->params.tx_cq_moderation.pkts = coal->tx_max_coalesced_frames;
 	priv->params.rx_cq_moderation.usec = coal->rx_coalesce_usecs;
 	priv->params.rx_cq_moderation.pkts = coal->rx_max_coalesced_frames;
 
-	if (!test_bit(MLX5E_STATE_OPENED, &priv->state))
+	if (!was_opened || restart)
 		goto out;
 
 	for (i = 0; i < priv->params.num_channels; ++i) {
@@ -570,8 +581,11 @@ static int mlx5e_set_coalesce(struct net_device *netdev,
 	}
 
 out:
+	if (was_opened && restart)
+		err = mlx5e_open_locked(netdev);
+
 	mutex_unlock(&priv->state_lock);
-	return 0;
+	return err;
 }
 
 static u32 ptys2ethtool_supported_link(u32 eth_proto_cap)

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -40,8 +40,9 @@
 #include "vxlan.h"
 
 struct mlx5e_rq_param {
-	u32                        rqc[MLX5_ST_SZ_DW(rqc)];
-	struct mlx5_wq_param       wq;
+	u32			rqc[MLX5_ST_SZ_DW(rqc)];
+	struct mlx5_wq_param	wq;
+	bool			am_enabled;
 };
 
 struct mlx5e_sq_param {
@@ -337,6 +338,9 @@ static int mlx5e_create_rq(struct mlx5e_channel *c,
 		wqe->data.byte_count = cpu_to_be32(byte_count);
 	}
 
+	INIT_WORK(&rq->am.work, mlx5e_rx_am_work);
+	rq->am.mode = priv->params.rx_cq_period_mode;
+
 	rq->wq_type = priv->params.rq_wq_type;
 	rq->pdev    = c->pdev;
 	rq->netdev  = c->netdev;
@@ -509,6 +513,9 @@ static int mlx5e_open_rq(struct mlx5e_channel *c,
 	if (err)
 		goto err_disable_rq;
 
+	if (param->am_enabled)
+		set_bit(MLX5E_RQ_STATE_AM, &c->rq.state);
+
 	set_bit(MLX5E_RQ_STATE_POST_WQES_ENABLE, &rq->state);
 
 	sq->ico_wqe_info[pi].opcode     = MLX5_OPCODE_NOP;
@@ -537,6 +544,8 @@ static void mlx5e_close_rq(struct mlx5e_rq *rq)
 	/* avoid destroying rq before mlx5e_poll_rx_cq() is done with it */
 	napi_synchronize(&rq->channel->napi);
 
+	cancel_work_sync(&rq->am.work);
+
 	mlx5e_disable_rq(rq);
 	mlx5e_destroy_rq(rq);
 }
@@ -1112,6 +1121,7 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
 {
 	struct mlx5e_cq_moder icosq_cq_moder = {0, 0};
 	struct net_device *netdev = priv->netdev;
+	struct mlx5e_cq_moder rx_cq_profile;
 	int cpu = mlx5e_get_cpu(priv, ix);
 	struct mlx5e_channel *c;
 	struct mlx5e_sq *sq;
@@ -1130,6 +1140,11 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
 	c->mkey_be  = cpu_to_be32(priv->mkey.key);
 	c->num_tc   = priv->params.num_tc;
 
+	if (priv->params.rx_am_enabled)
+		rx_cq_profile = mlx5e_am_get_def_profile(priv->params.rx_cq_period_mode);
+	else
+		rx_cq_profile = priv->params.rx_cq_moderation;
+
 	mlx5e_build_channeltc_to_txq_map(priv, ix);
 
 	netif_napi_add(netdev, &c->napi, mlx5e_napi_poll, 64);
@@ -1143,7 +1158,7 @@ static int mlx5e_open_channel(struct mlx5e_priv *priv, int ix,
 		goto err_close_icosq_cq;
 
 	err = mlx5e_open_cq(c, &cparam->rx_cq, &c->rq.cq,
-			    priv->params.rx_cq_moderation);
+			    rx_cq_profile);
 	if (err)
 		goto err_close_tx_cqs;
 
@@ -1243,6 +1258,8 @@ static void mlx5e_build_rq_param(struct mlx5e_priv *priv,
 
 	param->wq.buf_numa_node = dev_to_node(&priv->mdev->pdev->dev);
 	param->wq.linear = 1;
+
+	param->am_enabled = priv->params.rx_am_enabled;
 }
 
 static void mlx5e_build_drop_rq_param(struct mlx5e_rq_param *param)
@@ -2883,6 +2900,9 @@ static void mlx5e_build_netdev_priv(struct mlx5_core_dev *mdev,
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 	u32 link_speed = 0;
 	u32 pci_bw = 0;
+	u8 cq_period_mode = MLX5_CAP_GEN(mdev, cq_period_start_from_cqe) ?
+					 MLX5_CQ_PERIOD_MODE_START_FROM_CQE :
+					 MLX5_CQ_PERIOD_MODE_START_FROM_EQE;
 
 	priv->params.log_sq_size           =
 		MLX5E_PARAMS_DEFAULT_LOG_SQ_SIZE;
@@ -2929,8 +2949,8 @@ static void mlx5e_build_netdev_priv(struct mlx5_core_dev *mdev,
 	priv->params.min_rx_wqes = mlx5_min_rx_wqes(priv->params.rq_wq_type,
 					    BIT(priv->params.log_rq_size));
 
-	mlx5e_set_rx_cq_mode_params(&priv->params,
-				    MLX5_CQ_PERIOD_MODE_START_FROM_EQE);
+	priv->params.rx_am_enabled = MLX5_CAP_GEN(mdev, cq_moderation);
+	mlx5e_set_rx_cq_mode_params(&priv->params, cq_period_mode);
 
 	priv->params.tx_cq_moderation.usec =
 		MLX5E_PARAMS_DEFAULT_TX_CQ_MODERATION_USEC;