sky2: transmit ring 64 bit conservation
Stephen Hemminger [Tue, 18 Aug 2009 15:17:06 +0000 (15:17 +0000)]
This patch saves elements on transmit ring by only updating the upper
64 bit address when it changes. With many workloads skb's are located
in same region, so it saves space.

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

drivers/net/sky2.c
drivers/net/sky2.h

index fb841c8..88041e5 100644 (file)
@@ -1016,6 +1016,7 @@ static void tx_init(struct sky2_port *sky2)
        le = get_tx_le(sky2, &sky2->tx_prod);
        le->addr = 0;
        le->opcode = OP_ADDR64 | HW_OWNER;
+       sky2->tx_last_upper = 0;
 }
 
 static inline struct tx_ring_info *tx_le_re(struct sky2_port *sky2,
@@ -1573,8 +1574,9 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
        struct sky2_tx_le *le = NULL;
        struct tx_ring_info *re;
        unsigned i, len;
-       u16 slot;
        dma_addr_t mapping;
+       u32 upper;
+       u16 slot;
        u16 mss;
        u8 ctrl;
 
@@ -1593,9 +1595,11 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
                       dev->name, slot, skb->len);
 
        /* Send high bits if needed */
-       if (sizeof(dma_addr_t) > sizeof(u32)) {
+       upper = upper_32_bits(mapping);
+       if (upper != sky2->tx_last_upper) {
                le = get_tx_le(sky2, &slot);
-               le->addr = cpu_to_le32(upper_32_bits(mapping));
+               le->addr = cpu_to_le32(upper);
+               sky2->tx_last_upper = upper;
                le->opcode = OP_ADDR64 | HW_OWNER;
        }
 
@@ -1681,10 +1685,11 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
                if (pci_dma_mapping_error(hw->pdev, mapping))
                        goto mapping_unwind;
 
-               if (sizeof(dma_addr_t) > sizeof(u32)) {
+               upper = upper_32_bits(mapping);
+               if (upper != sky2->tx_last_upper) {
                        le = get_tx_le(sky2, &slot);
-                       le->addr = cpu_to_le32(upper_32_bits(mapping));
-                       le->ctrl = 0;
+                       le->addr = cpu_to_le32(upper);
+                       sky2->tx_last_upper = upper;
                        le->opcode = OP_ADDR64 | HW_OWNER;
                }
 
index 65b94c3..feb3204 100644 (file)
@@ -2017,6 +2017,7 @@ struct sky2_port {
 
        u16                  tx_pending;
        u16                  tx_last_mss;
+       u32                  tx_last_upper;
        u32                  tx_tcpsum;
 
        struct rx_ring_info  *rx_ring ____cacheline_aligned_in_smp;