pasemi_mac: RX performance tweaks

Various RX performance tweaks, do some explicit prefetching of packet
data, etc.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 12 insertions, 8 deletions

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index 0d80b9d48c26..f71a6864cdc2 100644
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -471,6 +471,7 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
                 rmb();
 
                 dp = &RX_DESC(mac, n);
+                prefetchw(dp);
                 macrx = dp->macrx;
 
                 if (!(macrx & XCT_MACRX_O))
@@ -492,8 +493,10 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
                         if (info->dma == dma)
                                 break;
                 }
+                prefetchw(info);
 
                 skb = info->skb;
+                prefetchw(skb);
                 info->dma = 0;
 
                 pci_unmap_single(mac->dma_pdev, dma, skb->len,
@@ -516,9 +519,7 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
 
                 skb_put(skb, len);
 
-                skb->protocol = eth_type_trans(skb, mac->netdev);
-
-                if ((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK) {
+                if (likely((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK)) {
                         skb->ip_summed = CHECKSUM_COMPLETE;
                         skb->csum = (macrx & XCT_MACRX_CSUM_M) >>
                                            XCT_MACRX_CSUM_S;
@@ -528,6 +529,7 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
                 mac->stats.rx_bytes += len;
                 mac->stats.rx_packets++;
 
+                skb->protocol = eth_type_trans(skb, mac->netdev);
                 netif_receive_skb(skb);
 
                 dp->ptr = 0;
@@ -559,7 +561,7 @@ static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
 
         for (i = start; i < mac->tx->next_to_use; i++) {
                 dp = &TX_DESC(mac, i);
-                if (!dp || (dp->mactx & XCT_MACTX_O))
+                if (unlikely(dp->mactx & XCT_MACTX_O))
                         break;
 
                 count++;
@@ -948,7 +950,7 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
         struct pasemi_mac_txring *txring;
         struct pasemi_mac_buffer *info;
         struct pas_dma_xct_descr *dp;
-        u64 dflags;
+        u64 dflags, mactx, ptr;
         dma_addr_t map;
         int flags;
 
@@ -976,6 +978,9 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
         if (dma_mapping_error(map))
                 return NETDEV_TX_BUSY;
 
+        mactx = dflags | XCT_MACTX_LLEN(skb->len);
+        ptr   = XCT_PTR_LEN(skb->len) | XCT_PTR_ADDR(map);
+
         txring = mac->tx;
 
         spin_lock_irqsave(&txring->lock, flags);
@@ -996,12 +1001,11 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
                 }
         }
 
-
         dp = &TX_DESC(mac, txring->next_to_use);
         info = &TX_DESC_INFO(mac, txring->next_to_use);
 
-        dp->mactx = dflags | XCT_MACTX_LLEN(skb->len);
-        dp->ptr   = XCT_PTR_LEN(skb->len) | XCT_PTR_ADDR(map);
+        dp->mactx = mactx;
+        dp->ptr   = ptr;
         info->dma = map;
         info->skb = skb;