[PATCH v3] net: bcmgenet: fix throughtput regression

From: Jaedon Shin
Date: Fri Feb 27 2015 - 21:48:57 EST

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This patch adds bcmgenet_tx_poll for the tx_rings. This can reduce the
interrupt load and send xmit in network stack on time. This also
separated for the completion of tx_ring16 from bcmgenet_poll.

The bcmgenet_tx_reclaim of tx_ring[{0,1,2,3}] operative by an interrupt
is to be not more than a certain number TxBDs. It is caused by too
slowly reclaiming the transmitted skb. Therefore, performance
degradation of xmit after 605ad7f ("tcp: refine TSO autosizing").

Signed-off-by: Jaedon Shin <jaedon.shin@xxxxxxxxx>
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
drivers/net/ethernet/broadcom/genet/bcmgenet.c | 111 +++++++++++++++++++------
drivers/net/ethernet/broadcom/genet/bcmgenet.h | 2 +
2 files changed, 87 insertions(+), 26 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index ff83c46b..d2979ac 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -971,13 +971,14 @@ static inline void bcmgenet_tx_ring_int_disable(struct bcmgenet_priv *priv,
}

/* Unlocked version of the reclaim routine */
-static void __bcmgenet_tx_reclaim(struct net_device *dev,
+static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev,
struct bcmgenet_tx_ring *ring)
{
struct bcmgenet_priv *priv = netdev_priv(dev);
int last_tx_cn, last_c_index, num_tx_bds;
struct enet_cb *tx_cb_ptr;
struct netdev_queue *txq;
+ unsigned int pkts_compl = 0;
unsigned int bds_compl;
unsigned int c_index;

@@ -1005,6 +1006,7 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev,
tx_cb_ptr = ring->cbs + last_c_index;
bds_compl = 0;
if (tx_cb_ptr->skb) {
+ pkts_compl++;
bds_compl = skb_shinfo(tx_cb_ptr->skb)->nr_frags + 1;
dev->stats.tx_bytes += tx_cb_ptr->skb->len;
dma_unmap_single(&dev->dev,
@@ -1028,23 +1030,45 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev,
last_c_index &= (num_tx_bds - 1);
}

- if (ring->free_bds > (MAX_SKB_FRAGS + 1))
- ring->int_disable(priv, ring);
-
- if (netif_tx_queue_stopped(txq))
- netif_tx_wake_queue(txq);
+ if (ring->free_bds > (MAX_SKB_FRAGS + 1)) {
+ if (netif_tx_queue_stopped(txq))
+ netif_tx_wake_queue(txq);
+ }

ring->c_index = c_index;
+
+ return pkts_compl;
}

-static void bcmgenet_tx_reclaim(struct net_device *dev,
+static unsigned int bcmgenet_tx_reclaim(struct net_device *dev,
struct bcmgenet_tx_ring *ring)
{
+ unsigned int released;
unsigned long flags;

spin_lock_irqsave(&ring->lock, flags);
- __bcmgenet_tx_reclaim(dev, ring);
+ released = __bcmgenet_tx_reclaim(dev, ring);
spin_unlock_irqrestore(&ring->lock, flags);
+
+ return released;
+}
+
+static int bcmgenet_tx_poll(struct napi_struct *napi, int budget)
+{
+ struct bcmgenet_tx_ring *ring =
+ container_of(napi, struct bcmgenet_tx_ring, napi);
+ unsigned int work_done = 0;
+
+ work_done = bcmgenet_tx_reclaim(ring->priv->dev, ring);
+
+ if (work_done == 0) {
+ napi_complete(napi);
+ ring->int_enable(ring->priv, ring);
+
+ return 0;
+ }
+
+ return budget;
}

static void bcmgenet_tx_reclaim_all(struct net_device *dev)
@@ -1302,10 +1326,8 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev)
bcmgenet_tdma_ring_writel(priv, ring->index,
ring->prod_index, TDMA_PROD_INDEX);

- if (ring->free_bds <= (MAX_SKB_FRAGS + 1)) {
+ if (ring->free_bds <= (MAX_SKB_FRAGS + 1))
netif_tx_stop_queue(txq);
- ring->int_enable(priv, ring);
- }

out:
spin_unlock_irqrestore(&ring->lock, flags);
@@ -1621,6 +1643,7 @@ static int init_umac(struct bcmgenet_priv *priv)
struct device *kdev = &priv->pdev->dev;
int ret;
u32 reg, cpu_mask_clear;
+ int index;

dev_dbg(&priv->pdev->dev, "bcmgenet: init_umac\n");

@@ -1647,7 +1670,7 @@ static int init_umac(struct bcmgenet_priv *priv)

bcmgenet_intr_disable(priv);

- cpu_mask_clear = UMAC_IRQ_RXDMA_BDONE;
+ cpu_mask_clear = UMAC_IRQ_RXDMA_BDONE | UMAC_IRQ_TXDMA_BDONE;

dev_dbg(kdev, "%s:Enabling RXDMA_BDONE interrupt\n", __func__);

@@ -1674,6 +1697,10 @@ static int init_umac(struct bcmgenet_priv *priv)

bcmgenet_intrl2_0_writel(priv, cpu_mask_clear, INTRL2_CPU_MASK_CLEAR);

+ for (index = 0; index < priv->hw_params->tx_queues; index++)
+ bcmgenet_intrl2_1_writel(priv, (1 << index),
+ INTRL2_CPU_MASK_CLEAR);
+
/* Enable rx/tx engine.*/
dev_dbg(kdev, "done init umac\n");

@@ -1693,6 +1720,8 @@ static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv,
unsigned int first_bd;

spin_lock_init(&ring->lock);
+ ring->priv = priv;
+ netif_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
ring->index = index;
if (index == DESC_INDEX) {
ring->queue = 0;
@@ -1738,6 +1767,17 @@ static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv,
TDMA_WRITE_PTR);
bcmgenet_tdma_ring_writel(priv, index, end_ptr * words_per_bd - 1,
DMA_END_ADDR);
+
+ napi_enable(&ring->napi);
+}
+
+static void bcmgenet_fini_tx_ring(struct bcmgenet_priv *priv,
+ unsigned int index)
+{
+ struct bcmgenet_tx_ring *ring = &priv->tx_rings[index];
+
+ napi_disable(&ring->napi);
+ netif_napi_del(&ring->napi);
}

/* Initialize a RDMA ring */
@@ -1907,7 +1947,7 @@ static int bcmgenet_dma_teardown(struct bcmgenet_priv *priv)
return ret;
}

-static void bcmgenet_fini_dma(struct bcmgenet_priv *priv)
+static void __bcmgenet_fini_dma(struct bcmgenet_priv *priv)
{
int i;

@@ -1926,6 +1966,18 @@ static void bcmgenet_fini_dma(struct bcmgenet_priv *priv)
kfree(priv->tx_cbs);
}

+static void bcmgenet_fini_dma(struct bcmgenet_priv *priv)
+{
+ int i;
+
+ bcmgenet_fini_tx_ring(priv, DESC_INDEX);
+
+ for (i = 0; i < priv->hw_params->tx_queues; i++)
+ bcmgenet_fini_tx_ring(priv, i);
+
+ __bcmgenet_fini_dma(priv);
+}
+
/* init_edma: Initialize DMA control register */
static int bcmgenet_init_dma(struct bcmgenet_priv *priv)
{
@@ -1952,7 +2004,7 @@ static int bcmgenet_init_dma(struct bcmgenet_priv *priv)
priv->tx_cbs = kcalloc(priv->num_tx_bds, sizeof(struct enet_cb),
GFP_KERNEL);
if (!priv->tx_cbs) {
- bcmgenet_fini_dma(priv);
+ __bcmgenet_fini_dma(priv);
return -ENOMEM;
}

@@ -1975,9 +2027,6 @@ static int bcmgenet_poll(struct napi_struct *napi, int budget)
struct bcmgenet_priv, napi);
unsigned int work_done;

- /* tx reclaim */
- bcmgenet_tx_reclaim(priv->dev, &priv->tx_rings[DESC_INDEX]);
-
work_done = bcmgenet_desc_rx(priv, budget);

/* Advancing our consumer index*/
@@ -2022,28 +2071,34 @@ static void bcmgenet_irq_task(struct work_struct *work)
static irqreturn_t bcmgenet_isr1(int irq, void *dev_id)
{
struct bcmgenet_priv *priv = dev_id;
+ struct bcmgenet_tx_ring *ring;
unsigned int index;

/* Save irq status for bottom-half processing. */
priv->irq1_stat =
bcmgenet_intrl2_1_readl(priv, INTRL2_CPU_STAT) &
- ~priv->int1_mask;
+ ~bcmgenet_intrl2_1_readl(priv, INTRL2_CPU_MASK_STATUS);
/* clear interrupts */
bcmgenet_intrl2_1_writel(priv, priv->irq1_stat, INTRL2_CPU_CLEAR);

netif_dbg(priv, intr, priv->dev,
"%s: IRQ=0x%x\n", __func__, priv->irq1_stat);
+
/* Check the MBDONE interrupts.
* packet is done, reclaim descriptors
*/
- if (priv->irq1_stat & 0x0000ffff) {
- index = 0;
- for (index = 0; index < 16; index++) {
- if (priv->irq1_stat & (1 << index))
- bcmgenet_tx_reclaim(priv->dev,
- &priv->tx_rings[index]);
+ for (index = 0; index < priv->hw_params->tx_queues; index++) {
+ if (!(priv->irq1_stat & BIT(index)))
+ continue;
+
+ ring = &priv->tx_rings[index];
+
+ if (likely(napi_schedule_prep(&ring->napi))) {
+ ring->int_disable(priv, ring);
+ __napi_schedule(&ring->napi);
}
}
+
return IRQ_HANDLED;
}

@@ -2075,8 +2130,12 @@ static irqreturn_t bcmgenet_isr0(int irq, void *dev_id)
}
if (priv->irq0_stat &
(UMAC_IRQ_TXDMA_BDONE | UMAC_IRQ_TXDMA_PDONE)) {
- /* Tx reclaim */
- bcmgenet_tx_reclaim(priv->dev, &priv->tx_rings[DESC_INDEX]);
+ struct bcmgenet_tx_ring *ring = &priv->tx_rings[DESC_INDEX];
+
+ if (likely(napi_schedule_prep(&ring->napi))) {
+ ring->int_disable(priv, ring);
+ __napi_schedule(&ring->napi);
+ }
}
if (priv->irq0_stat & (UMAC_IRQ_PHY_DET_R |
UMAC_IRQ_PHY_DET_F |
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.h b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
index b36ddec..0d370d1 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
@@ -520,6 +520,7 @@ struct bcmgenet_hw_params {

struct bcmgenet_tx_ring {
spinlock_t lock; /* ring lock */
+ struct napi_struct napi; /* NAPI per tx queue */
unsigned int index; /* ring index */
unsigned int queue; /* queue index */
struct enet_cb *cbs; /* tx ring buffer control block*/
@@ -534,6 +535,7 @@ struct bcmgenet_tx_ring {
struct bcmgenet_tx_ring *);
void (*int_disable)(struct bcmgenet_priv *priv,
struct bcmgenet_tx_ring *);
+ struct bcmgenet_priv *priv;
};

/* device context */
--
2.3.0

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Next message: Namhyung Kim: "Re: [PATCH] perf: fix building error"
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