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>

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index 0d80b9d..f71a686 100644 (file)
--- 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;