sky2: optimize transmit completion

Don't reference the list element in hardware transmit ring on transmit
completion. The list element is updated by hardware, therefore
it causes a cache miss. Do book keeping in software structure.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 49 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 7c1880d8b31f..a3e40d70c071 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1001,8 +1001,11 @@ static void sky2_prefetch_init(struct sky2_hw *hw, u32 qaddr,
 static inline struct sky2_tx_le *get_tx_le(struct sky2_port *sky2, u16 *slot)
 {
         struct sky2_tx_le *le = sky2->tx_le + *slot;
+        struct tx_ring_info *re = sky2->tx_ring + *slot;
 
         *slot = RING_NEXT(*slot, sky2->tx_ring_size);
+        re->flags = 0;
+        re->skb = NULL;
         le->ctrl = 0;
         return le;
 }
@@ -1021,12 +1024,6 @@ static void tx_init(struct sky2_port *sky2)
         sky2->tx_last_upper = 0;
 }
 
-static inline struct tx_ring_info *tx_le_re(struct sky2_port *sky2,
-                                            struct sky2_tx_le *le)
-{
-        return sky2->tx_ring + (le - sky2->tx_le);
-}
-
 /* Update chip's next pointer */
 static inline void sky2_put_idx(struct sky2_hw *hw, unsigned q, u16 idx)
 {
@@ -1563,6 +1560,19 @@ static unsigned tx_le_req(const struct sk_buff *skb)
         return count;
 }
 
+static void sky2_tx_unmap(struct pci_dev *pdev,
+                          const struct tx_ring_info *re)
+{
+        if (re->flags & TX_MAP_SINGLE)
+                pci_unmap_single(pdev, pci_unmap_addr(re, mapaddr),
+                                 pci_unmap_len(re, maplen),
+                                 PCI_DMA_TODEVICE);
+        else if (re->flags & TX_MAP_PAGE)
+                pci_unmap_page(pdev, pci_unmap_addr(re, mapaddr),
+                               pci_unmap_len(re, maplen),
+                               PCI_DMA_TODEVICE);
+}
+
 /*
  * Put one packet in ring for transmit.
  * A single packet can generate multiple list elements, and
@@ -1667,16 +1677,17 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
                 }
         }
 
+        re = sky2->tx_ring + slot;
+        re->flags = TX_MAP_SINGLE;
+        pci_unmap_addr_set(re, mapaddr, mapping);
+        pci_unmap_len_set(re, maplen, len);
+
         le = get_tx_le(sky2, &slot);
         le->addr = cpu_to_le32(lower_32_bits(mapping));
         le->length = cpu_to_le16(len);
         le->ctrl = ctrl;
         le->opcode = mss ? (OP_LARGESEND | HW_OWNER) : (OP_PACKET | HW_OWNER);
 
-        re = tx_le_re(sky2, le);
-        re->skb = skb;
-        pci_unmap_addr_set(re, mapaddr, mapping);
-        pci_unmap_len_set(re, maplen, len);
 
         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
@@ -1695,18 +1706,19 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
                         le->opcode = OP_ADDR64 | HW_OWNER;
                 }
 
+                re = sky2->tx_ring + slot;
+                re->flags = TX_MAP_PAGE;
+                pci_unmap_addr_set(re, mapaddr, mapping);
+                pci_unmap_len_set(re, maplen, frag->size);
+
                 le = get_tx_le(sky2, &slot);
                 le->addr = cpu_to_le32(lower_32_bits(mapping));
                 le->length = cpu_to_le16(frag->size);
                 le->ctrl = ctrl;
                 le->opcode = OP_BUFFER | HW_OWNER;
-
-                re = tx_le_re(sky2, le);
-                re->skb = skb;
-                pci_unmap_addr_set(re, mapaddr, mapping);
-                pci_unmap_len_set(re, maplen, frag->size);
         }
 
+        re->skb = skb;
         le->ctrl |= EOP;
 
         sky2->tx_prod = slot;
@@ -1720,23 +1732,9 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
 
 mapping_unwind:
         for (i = sky2->tx_prod; i != slot; i = RING_NEXT(i, sky2->tx_ring_size)) {
-                le = sky2->tx_le + i;
                 re = sky2->tx_ring + i;
 
-                switch(le->opcode & ~HW_OWNER) {
-                case OP_LARGESEND:
-                case OP_PACKET:
-                        pci_unmap_single(hw->pdev,
-                                         pci_unmap_addr(re, mapaddr),
-                                         pci_unmap_len(re, maplen),
-                                         PCI_DMA_TODEVICE);
-                        break;
-                case OP_BUFFER:
-                        pci_unmap_page(hw->pdev, pci_unmap_addr(re, mapaddr),
-                                       pci_unmap_len(re, maplen),
-                                       PCI_DMA_TODEVICE);
-                        break;
-                }
+                sky2_tx_unmap(hw->pdev, re);
         }
 
 mapping_error:
@@ -1759,34 +1757,18 @@ mapping_error:
 static void sky2_tx_complete(struct sky2_port *sky2, u16 done)
 {
         struct net_device *dev = sky2->netdev;
-        struct pci_dev *pdev = sky2->hw->pdev;
         unsigned idx;
 
         BUG_ON(done >= sky2->tx_ring_size);
 
         for (idx = sky2->tx_cons; idx != done;
              idx = RING_NEXT(idx, sky2->tx_ring_size)) {
-                struct sky2_tx_le *le = sky2->tx_le + idx;
                 struct tx_ring_info *re = sky2->tx_ring + idx;
+                struct sk_buff *skb = re->skb;
 
-                switch(le->opcode & ~HW_OWNER) {
-                case OP_LARGESEND:
-                case OP_PACKET:
-                        pci_unmap_single(pdev,
-                                         pci_unmap_addr(re, mapaddr),
-                                         pci_unmap_len(re, maplen),
-                                         PCI_DMA_TODEVICE);
-                        break;
-                case OP_BUFFER:
-                        pci_unmap_page(pdev, pci_unmap_addr(re, mapaddr),
-                                       pci_unmap_len(re, maplen),
-                                       PCI_DMA_TODEVICE);
-                        break;
-                }
-
-                if (le->ctrl & EOP) {
-                        struct sk_buff *skb = re->skb;
+                sky2_tx_unmap(sky2->hw->pdev, re);
 
+                if (skb) {
                         if (unlikely(netif_msg_tx_done(sky2)))
                                 printk(KERN_DEBUG "%s: tx done %u\n",
                                        dev->name, idx);