[PATCH] skge: Rx buffer optimization
Optimize the receive buffer management code to replenish the
buffers immediately (like tg3).
Signed-off-by: Stephen Hemmminger <shemminger@osdl.org>
diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index 9f24714..9d4ae78 100644
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -49,6 +49,8 @@
#define DEFAULT_RX_RING_SIZE 512
#define MAX_TX_RING_SIZE 1024
#define MAX_RX_RING_SIZE 4096
+#define RX_COPY_THRESHOLD 128
+#define RX_BUF_SIZE 1536
#define PHY_RETRIES 1000
#define ETH_JUMBO_MTU 9000
#define TX_WATCHDOG (5 * HZ)
@@ -746,6 +748,7 @@
for (i = 0, e = ring->start, d = vaddr; i < ring->count; i++, e++, d++) {
e->desc = d;
+ e->skb = NULL;
if (i == ring->count - 1) {
e->next = ring->start;
d->next_offset = base;
@@ -759,24 +762,23 @@
return 0;
}
-/* Setup buffer for receiving */
-static inline int skge_rx_alloc(struct skge_port *skge,
- struct skge_element *e)
+static struct sk_buff *skge_rx_alloc(struct net_device *dev, unsigned int size)
{
- unsigned long bufsize = skge->netdev->mtu + ETH_HLEN; /* VLAN? */
- struct skge_rx_desc *rd = e->desc;
- struct sk_buff *skb;
- u64 map;
+ struct sk_buff *skb = dev_alloc_skb(size);
- skb = dev_alloc_skb(bufsize + NET_IP_ALIGN);
- if (unlikely(!skb)) {
- printk(KERN_DEBUG PFX "%s: out of memory for receive\n",
- skge->netdev->name);
- return -ENOMEM;
+ if (likely(skb)) {
+ skb->dev = dev;
+ skb_reserve(skb, NET_IP_ALIGN);
}
+ return skb;
+}
- skb->dev = skge->netdev;
- skb_reserve(skb, NET_IP_ALIGN);
+/* Allocate and setup a new buffer for receiving */
+static void skge_rx_setup(struct skge_port *skge, struct skge_element *e,
+ struct sk_buff *skb, unsigned int bufsize)
+{
+ struct skge_rx_desc *rd = e->desc;
+ u64 map;
map = pci_map_single(skge->hw->pdev, skb->data, bufsize,
PCI_DMA_FROMDEVICE);
@@ -794,55 +796,69 @@
rd->control = BMU_OWN | BMU_STF | BMU_IRQ_EOF | BMU_TCP_CHECK | bufsize;
pci_unmap_addr_set(e, mapaddr, map);
pci_unmap_len_set(e, maplen, bufsize);
- return 0;
}
-/* Free all unused buffers in receive ring, assumes receiver stopped */
+/* Resume receiving using existing skb,
+ * Note: DMA address is not changed by chip.
+ * MTU not changed while receiver active.
+ */
+static void skge_rx_reuse(struct skge_element *e, unsigned int size)
+{
+ struct skge_rx_desc *rd = e->desc;
+
+ rd->csum2 = 0;
+ rd->csum2_start = ETH_HLEN;
+
+ wmb();
+
+ rd->control = BMU_OWN | BMU_STF | BMU_IRQ_EOF | BMU_TCP_CHECK | size;
+}
+
+
+/* Free all buffers in receive ring, assumes receiver stopped */
static void skge_rx_clean(struct skge_port *skge)
{
struct skge_hw *hw = skge->hw;
struct skge_ring *ring = &skge->rx_ring;
struct skge_element *e;
- for (e = ring->to_clean; e != ring->to_use; e = e->next) {
+ e = ring->start;
+ do {
struct skge_rx_desc *rd = e->desc;
rd->control = 0;
-
- pci_unmap_single(hw->pdev,
- pci_unmap_addr(e, mapaddr),
- pci_unmap_len(e, maplen),
- PCI_DMA_FROMDEVICE);
- dev_kfree_skb(e->skb);
- e->skb = NULL;
- }
- ring->to_clean = e;
+ if (e->skb) {
+ pci_unmap_single(hw->pdev,
+ pci_unmap_addr(e, mapaddr),
+ pci_unmap_len(e, maplen),
+ PCI_DMA_FROMDEVICE);
+ dev_kfree_skb(e->skb);
+ e->skb = NULL;
+ }
+ } while ((e = e->next) != ring->start);
}
+
/* Allocate buffers for receive ring
- * For receive: to_use is refill location
- * to_clean is next received frame.
- *
- * if (to_use == to_clean)
- * then ring all frames in ring need buffers
- * if (to_use->next == to_clean)
- * then ring all frames in ring have buffers
+ * For receive: to_clean is next received frame.
*/
static int skge_rx_fill(struct skge_port *skge)
{
struct skge_ring *ring = &skge->rx_ring;
struct skge_element *e;
- int ret = 0;
+ unsigned int bufsize = skge->rx_buf_size;
- for (e = ring->to_use; e->next != ring->to_clean; e = e->next) {
- if (skge_rx_alloc(skge, e)) {
- ret = 1;
- break;
- }
+ e = ring->start;
+ do {
+ struct sk_buff *skb = skge_rx_alloc(skge->netdev, bufsize);
- }
- ring->to_use = e;
+ if (!skb)
+ return -ENOMEM;
- return ret;
+ skge_rx_setup(skge, e, skb, bufsize);
+ } while ( (e = e->next) != ring->start);
+
+ ring->to_clean = ring->start;
+ return 0;
}
static void skge_link_up(struct skge_port *skge)
@@ -2048,6 +2064,12 @@
if (netif_msg_ifup(skge))
printk(KERN_INFO PFX "%s: enabling interface\n", dev->name);
+ if (dev->mtu > RX_BUF_SIZE)
+ skge->rx_buf_size = dev->mtu + ETH_HLEN + NET_IP_ALIGN;
+ else
+ skge->rx_buf_size = RX_BUF_SIZE;
+
+
rx_size = skge->rx_ring.count * sizeof(struct skge_rx_desc);
tx_size = skge->tx_ring.count * sizeof(struct skge_tx_desc);
skge->mem_size = tx_size + rx_size;
@@ -2060,7 +2082,8 @@
if ((err = skge_ring_alloc(&skge->rx_ring, skge->mem, skge->dma)))
goto free_pci_mem;
- if (skge_rx_fill(skge))
+ err = skge_rx_fill(skge);
+ if (err)
goto free_rx_ring;
if ((err = skge_ring_alloc(&skge->tx_ring, skge->mem + rx_size,
@@ -2284,6 +2307,7 @@
static inline void skge_tx_free(struct skge_hw *hw, struct skge_element *e)
{
+ /* This ring element can be skb or fragment */
if (e->skb) {
pci_unmap_single(hw->pdev,
pci_unmap_addr(e, mapaddr),
@@ -2328,16 +2352,17 @@
static int skge_change_mtu(struct net_device *dev, int new_mtu)
{
int err = 0;
+ int running = netif_running(dev);
if (new_mtu < ETH_ZLEN || new_mtu > ETH_JUMBO_MTU)
return -EINVAL;
- dev->mtu = new_mtu;
- if (netif_running(dev)) {
+ if (running)
skge_down(dev);
+ dev->mtu = new_mtu;
+ if (running)
skge_up(dev);
- }
return err;
}
@@ -2436,28 +2461,76 @@
printk(KERN_DEBUG PFX "%s: rx err, slot %d control 0x%x status 0x%x\n",
skge->netdev->name, slot, control, status);
- if ((control & (BMU_EOF|BMU_STF)) != (BMU_STF|BMU_EOF)
- || (control & BMU_BBC) > skge->netdev->mtu + VLAN_ETH_HLEN)
+ if ((control & (BMU_EOF|BMU_STF)) != (BMU_STF|BMU_EOF))
skge->net_stats.rx_length_errors++;
- else {
- if (skge->hw->chip_id == CHIP_ID_GENESIS) {
- if (status & (XMR_FS_RUNT|XMR_FS_LNG_ERR))
- skge->net_stats.rx_length_errors++;
- if (status & XMR_FS_FRA_ERR)
- skge->net_stats.rx_frame_errors++;
- if (status & XMR_FS_FCS_ERR)
- skge->net_stats.rx_crc_errors++;
- } else {
- if (status & (GMR_FS_LONG_ERR|GMR_FS_UN_SIZE))
- skge->net_stats.rx_length_errors++;
- if (status & GMR_FS_FRAGMENT)
- skge->net_stats.rx_frame_errors++;
- if (status & GMR_FS_CRC_ERR)
- skge->net_stats.rx_crc_errors++;
- }
+ else if (skge->hw->chip_id == CHIP_ID_GENESIS) {
+ if (status & (XMR_FS_RUNT|XMR_FS_LNG_ERR))
+ skge->net_stats.rx_length_errors++;
+ if (status & XMR_FS_FRA_ERR)
+ skge->net_stats.rx_frame_errors++;
+ if (status & XMR_FS_FCS_ERR)
+ skge->net_stats.rx_crc_errors++;
+ } else {
+ if (status & (GMR_FS_LONG_ERR|GMR_FS_UN_SIZE))
+ skge->net_stats.rx_length_errors++;
+ if (status & GMR_FS_FRAGMENT)
+ skge->net_stats.rx_frame_errors++;
+ if (status & GMR_FS_CRC_ERR)
+ skge->net_stats.rx_crc_errors++;
}
}
+/* Get receive buffer from descriptor.
+ * Handles copy of small buffers and reallocation failures
+ */
+static inline struct sk_buff *skge_rx_get(struct skge_port *skge,
+ struct skge_element *e,
+ unsigned int len)
+{
+ struct sk_buff *nskb, *skb;
+
+ if (len < RX_COPY_THRESHOLD) {
+ nskb = skge_rx_alloc(skge->netdev, len + NET_IP_ALIGN);
+ if (unlikely(!nskb))
+ return NULL;
+
+ pci_dma_sync_single_for_cpu(skge->hw->pdev,
+ pci_unmap_addr(e, mapaddr),
+ len, PCI_DMA_FROMDEVICE);
+ memcpy(nskb->data, e->skb->data, len);
+ pci_dma_sync_single_for_device(skge->hw->pdev,
+ pci_unmap_addr(e, mapaddr),
+ len, PCI_DMA_FROMDEVICE);
+
+ if (skge->rx_csum) {
+ struct skge_rx_desc *rd = e->desc;
+ nskb->csum = le16_to_cpu(rd->csum2);
+ nskb->ip_summed = CHECKSUM_HW;
+ }
+ skge_rx_reuse(e, skge->rx_buf_size);
+ return nskb;
+ } else {
+ nskb = skge_rx_alloc(skge->netdev, skge->rx_buf_size);
+ if (unlikely(!nskb))
+ return NULL;
+
+ pci_unmap_single(skge->hw->pdev,
+ pci_unmap_addr(e, mapaddr),
+ pci_unmap_len(e, maplen),
+ PCI_DMA_FROMDEVICE);
+ skb = e->skb;
+ if (skge->rx_csum) {
+ struct skge_rx_desc *rd = e->desc;
+ skb->csum = le16_to_cpu(rd->csum2);
+ skb->ip_summed = CHECKSUM_HW;
+ }
+
+ skge_rx_setup(skge, e, nskb, skge->rx_buf_size);
+ return skb;
+ }
+}
+
+
static int skge_poll(struct net_device *dev, int *budget)
{
struct skge_port *skge = netdev_priv(dev);
@@ -2466,14 +2539,12 @@
struct skge_element *e;
unsigned int to_do = min(dev->quota, *budget);
unsigned int work_done = 0;
- int done;
pr_debug("skge_poll\n");
- for (e = ring->to_clean; e != ring->to_use && work_done < to_do;
- e = e->next) {
+ for (e = ring->to_clean; work_done < to_do; e = e->next) {
struct skge_rx_desc *rd = e->desc;
- struct sk_buff *skb = e->skb;
+ struct sk_buff *skb;
u32 control, len, status;
rmb();
@@ -2482,19 +2553,12 @@
break;
len = control & BMU_BBC;
- e->skb = NULL;
-
- pci_unmap_single(hw->pdev,
- pci_unmap_addr(e, mapaddr),
- pci_unmap_len(e, maplen),
- PCI_DMA_FROMDEVICE);
-
status = rd->status;
- if ((control & (BMU_EOF|BMU_STF)) != (BMU_STF|BMU_EOF)
- || len > dev->mtu + VLAN_ETH_HLEN
- || bad_phy_status(hw, status)) {
+
+ if (unlikely((control & (BMU_EOF|BMU_STF)) != (BMU_STF|BMU_EOF)
+ || bad_phy_status(hw, status))) {
skge_rx_error(skge, e - ring->start, control, status);
- dev_kfree_skb(skb);
+ skge_rx_reuse(e, skge->rx_buf_size);
continue;
}
@@ -2502,42 +2566,37 @@
printk(KERN_DEBUG PFX "%s: rx slot %td status 0x%x len %d\n",
dev->name, e - ring->start, rd->status, len);
- skb_put(skb, len);
- skb->protocol = eth_type_trans(skb, dev);
+ skb = skge_rx_get(skge, e, len);
+ if (likely(skb)) {
+ skb_put(skb, len);
+ skb->protocol = eth_type_trans(skb, dev);
- if (skge->rx_csum) {
- skb->csum = le16_to_cpu(rd->csum2);
- skb->ip_summed = CHECKSUM_HW;
- }
+ dev->last_rx = jiffies;
+ netif_receive_skb(skb);
- dev->last_rx = jiffies;
- netif_receive_skb(skb);
-
- ++work_done;
+ ++work_done;
+ } else
+ skge_rx_reuse(e, skge->rx_buf_size);
}
ring->to_clean = e;
- *budget -= work_done;
- dev->quota -= work_done;
- done = work_done < to_do;
-
- if (skge_rx_fill(skge))
- done = 0;
-
/* restart receiver */
wmb();
skge_write8(hw, Q_ADDR(rxqaddr[skge->port], Q_CSR),
CSR_START | CSR_IRQ_CL_F);
- if (done) {
- local_irq_disable();
- __netif_rx_complete(dev);
- hw->intr_mask |= portirqmask[skge->port];
- skge_write32(hw, B0_IMSK, hw->intr_mask);
- local_irq_enable();
- }
+ *budget -= work_done;
+ dev->quota -= work_done;
- return !done;
+ if (work_done >= to_do)
+ return 1; /* not done */
+
+ local_irq_disable();
+ __netif_rx_complete(dev);
+ hw->intr_mask |= portirqmask[skge->port];
+ skge_write32(hw, B0_IMSK, hw->intr_mask);
+ local_irq_enable();
+ return 0;
}
static inline void skge_tx_intr(struct net_device *dev)