Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 46afd0fb authored by Yevgeny Petrilin's avatar Yevgeny Petrilin Committed by David S. Miller
Browse files

mlx4_en: optimize adaptive moderation algorithm for better latency 



Signed-off-by: default avatarYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 39f17b44

drivers/net/mlx4/en_netdev.c

+5 −13
Original line number Diff line number Diff line
@@ -417,7 +417,6 @@ static void mlx4_en_auto_moderation(struct mlx4_en_priv *priv) 
	unsigned long avg_pkt_size;

	unsigned long rx_packets;

	unsigned long rx_bytes;

	unsigned long rx_byte_diff;

	unsigned long tx_packets;

	unsigned long tx_pkt_diff;

	unsigned long rx_pkt_diff;
@@ -441,25 +440,20 @@ static void mlx4_en_auto_moderation(struct mlx4_en_priv *priv) 
	rx_pkt_diff = ((unsigned long) (rx_packets -

					priv->last_moder_packets));

	packets = max(tx_pkt_diff, rx_pkt_diff);

	rx_byte_diff = rx_bytes - priv->last_moder_bytes;

	rx_byte_diff = rx_byte_diff ? rx_byte_diff : 1;

	rate = packets * HZ / period;

	avg_pkt_size = packets ? ((unsigned long) (rx_bytes -

				 priv->last_moder_bytes)) / packets : 0;



	/* Apply auto-moderation only when packet rate exceeds a rate that

	 * it matters */

	if (rate > MLX4_EN_RX_RATE_THRESH) {

	if (rate > MLX4_EN_RX_RATE_THRESH && avg_pkt_size > MLX4_EN_AVG_PKT_SMALL) {

		/* If tx and rx packet rates are not balanced, assume that

		 * traffic is mainly BW bound and apply maximum moderation.

		 * Otherwise, moderate according to packet rate */

		if (2 * tx_pkt_diff > 3 * rx_pkt_diff &&

		    rx_pkt_diff / rx_byte_diff <

		    MLX4_EN_SMALL_PKT_SIZE)

			moder_time = priv->rx_usecs_low;

		else if (2 * rx_pkt_diff > 3 * tx_pkt_diff)

		if (2 * tx_pkt_diff > 3 * rx_pkt_diff ||

		    2 * rx_pkt_diff > 3 * tx_pkt_diff) {

			moder_time = priv->rx_usecs_high;

		else {

		} else {

			if (rate < priv->pkt_rate_low)

				moder_time = priv->rx_usecs_low;

			else if (rate > priv->pkt_rate_high)
@@ -471,9 +465,7 @@ static void mlx4_en_auto_moderation(struct mlx4_en_priv *priv) 
					priv->rx_usecs_low;

		}

	} else {

		/* When packet rate is low, use default moderation rather than

		 * 0 to prevent interrupt storms if traffic suddenly increases */

		moder_time = priv->rx_usecs;

		moder_time = priv->rx_usecs_low;

	}



	en_dbg(INTR, priv, "tx rate:%lu rx_rate:%lu\n",

drivers/net/mlx4/mlx4_en.h

+1 −0
Original line number Diff line number Diff line
@@ -124,6 +124,7 @@ enum { 
#define MLX4_EN_RX_SIZE_THRESH		1024

#define MLX4_EN_RX_RATE_THRESH		(1000000 / MLX4_EN_RX_COAL_TIME_HIGH)

#define MLX4_EN_SAMPLE_INTERVAL		0

#define MLX4_EN_AVG_PKT_SMALL		256



#define MLX4_EN_AUTO_CONF	0xffff