From mboxrd@z Thu Jan 1 00:00:00 1970 From: Beniamino Galvani Subject: [PATCH net-next] net: stmmac: add BQL support Date: Sun, 28 Dec 2014 15:57:11 +0100 Message-ID: <1419778631-23067-1-git-send-email-b.galvani@gmail.com> Cc: Giuseppe Cavallaro , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Beniamino Galvani To: "David S. Miller" Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Add support for Byte Queue Limits to the STMicro MAC driver. Tested on a Amlogic S805 Cortex-A5 board, where the use of BQL slightly decreases the ping latency from ~10ms to ~3ms when the 100Mbps link is saturated by TCP streams. No difference is observed at 1Gbps. Signed-off-by: Beniamino Galvani --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 118a427..c5af3d8 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -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++; @@ -2049,6 +2057,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) skb_tx_timestamp(skb); priv->hw->dma->enable_dma_transmission(priv->ioaddr); + netdev_sent_queue(dev, skb->len); spin_unlock(&priv->tx_lock); return NETDEV_TX_OK; -- 2.1.4