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From: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
To: netdev@vger.kernel.org
Cc: bhutchings@solarflare.com, davem@davemloft.net,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>
Subject: [net-next.git 3/7] stmmac: add the initial tx coalesce schema
Date: Wed,  5 Sep 2012 17:03:48 +0200	[thread overview]
Message-ID: <1346857432-24657-4-git-send-email-peppe.cavallaro@st.com> (raw)
In-Reply-To: <1346857432-24657-1-git-send-email-peppe.cavallaro@st.com>

This patch adds a new schema used for mitigating the
number of transmit interrupts.
It is based on a sw timer and a threshold value.
The timer is used to periodically call the stmmac_tx
function that can be invoked by the ISR but only for
the descriptors where the interrupt on completion
field has been set. This is tuned by a threshold.

Next step is to add the ability to tune these coalesce
values by ethtool.

Till now I have put a default that showed a real gain
on all the platforms ARM/SH4 where I performed benchmarks.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/common.h       |    8 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac.h       |    4 +
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c   |    9 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c  |   86 +++++++++++++-------
 4 files changed, 72 insertions(+), 35 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index bd32fe6..1d6bd3e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -95,11 +95,13 @@ struct stmmac_extra_stats {
 	unsigned long threshold;
 	unsigned long tx_pkt_n;
 	unsigned long rx_pkt_n;
-	unsigned long rx_napi_poll;
+	unsigned long normal_irq_n;
 	unsigned long rx_normal_irq_n;
+	unsigned long rx_napi_poll;
 	unsigned long tx_normal_irq_n;
-	unsigned long sched_timer_n;
-	unsigned long normal_irq_n;
+	unsigned long txtimer;
+	unsigned long tx_clean;
+	unsigned long tx_reset_ic_bit;
 	unsigned long mmc_tx_irq_n;
 	unsigned long mmc_rx_irq_n;
 	unsigned long mmc_rx_csum_offload_irq_n;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 9f35769..0f5ab28 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -88,6 +88,10 @@ struct stmmac_priv {
 	int eee_enabled;
 	int eee_active;
 	int tx_lpi_timer;
+	struct timer_list txtimer;
+	u32 tx_count_frames;
+	u32 tx_coal_frames;
+	u32 tx_coal_timer;
 };
 
 extern int phyaddr;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 505fe71..48ad0bc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -90,12 +90,13 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(threshold),
 	STMMAC_STAT(tx_pkt_n),
 	STMMAC_STAT(rx_pkt_n),
-	STMMAC_STAT(rx_napi_poll),
+	STMMAC_STAT(normal_irq_n),
 	STMMAC_STAT(rx_normal_irq_n),
+	STMMAC_STAT(rx_napi_poll),
 	STMMAC_STAT(tx_normal_irq_n),
-	STMMAC_STAT(sched_timer_n),
-	STMMAC_STAT(normal_irq_n),
-	STMMAC_STAT(normal_irq_n),
+	STMMAC_STAT(txtimer),
+	STMMAC_STAT(tx_clean),
+	STMMAC_STAT(tx_reset_ic_bit),
 	STMMAC_STAT(mmc_tx_irq_n),
 	STMMAC_STAT(mmc_rx_irq_n),
 	STMMAC_STAT(mmc_rx_csum_offload_irq_n),
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b247c39..d7f5482 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -77,6 +77,8 @@
 
 #define STMMAC_ALIGN(x)	L1_CACHE_ALIGN(x)
 #define JUMBO_LEN	9000
+#define	STMMAC_TX_TM	40000
+#define STMMAC_TX_MAX_FRAMES	64	/* Max coalesced frame */
 
 /* Module parameters */
 #define TX_TIMEO 5000 /* default 5 seconds */
@@ -695,8 +697,11 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
 static void stmmac_tx(struct stmmac_priv *priv)
 {
 	unsigned int txsize = priv->dma_tx_size;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->tx_lock, flags);
 
-	spin_lock(&priv->tx_lock);
+	priv->xstats.tx_clean++;
 
 	while (priv->dirty_tx != priv->cur_tx) {
 		int last;
@@ -765,7 +770,7 @@ static void stmmac_tx(struct stmmac_priv *priv)
 		stmmac_enable_eee_mode(priv);
 		mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_TIMER(eee_timer));
 	}
-	spin_unlock(&priv->tx_lock);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
 }
 
 static inline void stmmac_enable_irq(struct stmmac_priv *priv)
@@ -778,29 +783,16 @@ static inline void stmmac_disable_irq(struct stmmac_priv *priv)
 	priv->hw->dma->disable_dma_irq(priv->ioaddr);
 }
 
-static int stmmac_has_work(struct stmmac_priv *priv)
+static void stmmac_txtimer(unsigned long data)
 {
-	unsigned int has_work = 0;
-	int rxret, tx_work = 0;
+	struct stmmac_priv *priv = (struct stmmac_priv *)data;
 
-	rxret = priv->hw->desc->get_rx_owner(priv->dma_rx +
-		(priv->cur_rx % priv->dma_rx_size));
+	priv->xstats.txtimer++;
 
 	if (priv->dirty_tx != priv->cur_tx)
-		tx_work = 1;
-
-	if (likely(!rxret || tx_work))
-		has_work = 1;
+		stmmac_tx(priv);
 
-	return has_work;
-}
-
-static inline void _stmmac_schedule(struct stmmac_priv *priv)
-{
-	if (likely(stmmac_has_work(priv))) {
-		stmmac_disable_irq(priv);
-		napi_schedule(&priv->napi);
-	}
+	return;
 }
 
 /**
@@ -824,7 +816,7 @@ static void stmmac_tx_err(struct stmmac_priv *priv)
 	netif_wake_queue(priv->dev);
 }
 
-static inline void stmmac_rx_schedule(struct stmmac_priv *priv)
+static void stmmac_rx_schedule(struct stmmac_priv *priv)
 {
 	if (likely(napi_schedule_prep(&priv->napi))) {
 		stmmac_disable_irq(priv);
@@ -1001,6 +993,36 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 				   priv->dma_rx_phy);
 }
 
+static int stmmac_check_coal(int size, int max_coal_frames)
+{
+	int ret = 0;
+
+	if (max_coal_frames >= size)
+		return ret;
+
+	return max_coal_frames;
+}
+
+static int stmmac_init_tx_coalesce(struct stmmac_priv *priv)
+{
+	int ret = -EOPNOTSUPP;
+
+	priv->tx_coal_frames = stmmac_check_coal(priv->dma_tx_size,
+						 STMMAC_TX_MAX_FRAMES);
+	if (priv->tx_coal_frames) {
+		/* Set Tx coalesce parameters and timers */
+		priv->tx_coal_timer = jiffies + usecs_to_jiffies(STMMAC_TX_TM);
+		init_timer(&priv->txtimer);
+		priv->txtimer.expires = priv->tx_coal_timer;
+		priv->txtimer.data = (unsigned long)priv;
+		priv->txtimer.function = stmmac_txtimer;
+
+		ret = 0;
+	}
+
+	return ret;
+}
+
 /**
  *  stmmac_open - open entry point of the driver
  *  @dev : pointer to the device structure.
@@ -1113,6 +1135,10 @@ static int stmmac_open(struct net_device *dev)
 	priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS_TIMER;
 	priv->eee_enabled = stmmac_eee_init(priv);
 
+	ret = stmmac_init_tx_coalesce(priv);
+	if (!ret)
+		add_timer(&priv->txtimer);
+
 	napi_enable(&priv->napi);
 	skb_queue_head_init(&priv->rx_recycle);
 	netif_start_queue(dev);
@@ -1202,6 +1228,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	int nfrags = skb_shinfo(skb)->nr_frags;
 	struct dma_desc *desc, *first;
 	unsigned int nopaged_len = skb_headlen(skb);
+	unsigned long flags;
 
 	if (unlikely(stmmac_tx_avail(priv) < nfrags + 1)) {
 		if (!netif_queue_stopped(dev)) {
@@ -1213,10 +1240,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		return NETDEV_TX_BUSY;
 	}
 
-	spin_lock(&priv->tx_lock);
-
-	if (priv->tx_path_in_lpi_mode)
-		stmmac_disable_eee_mode(priv);
+	spin_lock_irqsave(&priv->tx_lock, flags);
 
 	entry = priv->cur_tx % txsize;
 
@@ -1272,7 +1296,14 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Interrupt on completition only for the latest segment */
 	priv->hw->desc->close_tx_desc(desc);
 
-	wmb();
+	/* Do not set the IC according to the coalesce patameters */
+	priv->tx_count_frames++;
+	if (priv->tx_coal_frames > priv->tx_count_frames) {
+		priv->hw->desc->clear_tx_ic(desc);
+		priv->xstats.tx_reset_ic_bit++;
+		mod_timer(&priv->txtimer, priv->tx_coal_timer);
+	} else
+		priv->tx_count_frames = 0;
 
 	/* To avoid raise condition */
 	priv->hw->desc->set_tx_owner(first);
@@ -1302,7 +1333,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	priv->hw->dma->enable_dma_transmission(priv->ioaddr);
 
-	spin_unlock(&priv->tx_lock);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
 
 	return NETDEV_TX_OK;
 }
@@ -1447,7 +1478,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
  *	      all interfaces.
  *  Description :
  *   This function implements the the reception process.
- *   Also it runs the TX completion thread
  */
 static int stmmac_poll(struct napi_struct *napi, int budget)
 {
-- 
1.7.4.4

  parent reply	other threads:[~2012-09-05 15:04 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-05 15:03 [net-next.git 0/7 (V2)] stmmac: remove dead code for STMMAC_TIMER and add new mitigation schema Giuseppe CAVALLARO
2012-09-05 15:03 ` [net-next.git 1/7] stmmac: remove dead code for TIMER Giuseppe CAVALLARO
2012-09-05 15:03 ` [net-next.git 2/7] stmmac: manage tx clean out of rx_poll Giuseppe CAVALLARO
2012-09-05 15:51   ` Ben Hutchings
2012-09-05 15:03 ` Giuseppe CAVALLARO [this message]
2012-09-05 16:11   ` [net-next.git 3/7] stmmac: add the initial tx coalesce schema Ben Hutchings
2012-09-05 15:03 ` [net-next.git 4/7] stmmac: add Rx watchdog optimization to mitigate the DMA irqs Giuseppe CAVALLARO
2012-09-05 16:14   ` Ben Hutchings
2012-09-05 17:16     ` David Miller
2012-09-06  6:06       ` Giuseppe CAVALLARO
2012-09-05 15:03 ` [net-next.git 5/7] stmmac: get/set coalesce parameters via ethtool Giuseppe CAVALLARO
2012-09-05 15:03 ` [net-next.git 6/7] stmmac: update the doc with new IRQ mitigation Giuseppe CAVALLARO
2012-09-05 15:03 ` [net-next.git 7/7] stmmac: update the driver version to Sept_2012 Giuseppe CAVALLARO
  -- strict thread matches above, loose matches on Subject: below --
2012-09-03  7:46 [net-next.git 0/7] stmmac: remove dead code for STMMAC_TIMER and add new mitigation schema Giuseppe CAVALLARO
2012-09-03  7:46 ` [net-next.git 3/7] stmmac: add the initial tx coalesce schema Giuseppe CAVALLARO

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