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Commit 38979574 authored by Beniamino Galvani's avatar Beniamino Galvani Committed by David S. Miller
Browse files

net: stmmac: add BQL support 



Add support for Byte Queue Limits to the STMicro MAC driver.

Tested on a Amlogic S802 quad Cortex-A9 board, where the use of BQL
decreases the latency of a high priority ping from ~12ms to ~1ms when
the 100Mbit link is saturated by 20 TCP streams.

Signed-off-by: default avatarBeniamino Galvani <b.galvani@gmail.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1793c798

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+9 −0
Original line number Diff line number Diff line
@@ -1097,6 +1097,7 @@ static int init_dma_desc_rings(struct net_device *dev, gfp_t flags) 


	priv->dirty_tx = 0;

	priv->cur_tx = 0;

	netdev_reset_queue(priv->dev);



	stmmac_clear_descriptors(priv);
@@ -1300,6 +1301,7 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv) 
static void stmmac_tx_clean(struct stmmac_priv *priv)

{

	unsigned int txsize = priv->dma_tx_size;

	unsigned int bytes_compl = 0, pkts_compl = 0;



	spin_lock(&priv->tx_lock);
@@ -1356,6 +1358,8 @@ static void stmmac_tx_clean(struct stmmac_priv *priv) 
		priv->hw->mode->clean_desc3(priv, p);



		if (likely(skb != NULL)) {

			pkts_compl++;

			bytes_compl += skb->len;

			dev_consume_skb_any(skb);

			priv->tx_skbuff[entry] = NULL;

		}
@@ -1364,6 +1368,9 @@ static void stmmac_tx_clean(struct stmmac_priv *priv) 


		priv->dirty_tx++;

	}



	netdev_completed_queue(priv->dev, pkts_compl, bytes_compl);



	if (unlikely(netif_queue_stopped(priv->dev) &&

		     stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv))) {

		netif_tx_lock(priv->dev);
@@ -1418,6 +1425,7 @@ static void stmmac_tx_err(struct stmmac_priv *priv) 
						     (i == txsize - 1));

	priv->dirty_tx = 0;

	priv->cur_tx = 0;

	netdev_reset_queue(priv->dev);

	priv->hw->dma->start_tx(priv->ioaddr);



	priv->dev->stats.tx_errors++;
@@ -2050,6 +2058,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (!priv->hwts_tx_en)

		skb_tx_timestamp(skb);



	netdev_sent_queue(dev, skb->len);

	priv->hw->dma->enable_dma_transmission(priv->ioaddr);



	spin_unlock(&priv->tx_lock);