[PATCH] sky2: optimize checksum offload information

Since many packets have the same checksum starting offset and insertion
location; the driver can save the last information and only tell hardware
when it changes.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index fe60f04..eafb632 100644 (file)
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1280,12 +1280,17 @@ static int sky2_xmit_frame(struct sk_buff *skb, struct net_device *dev)
                if (skb->nh.iph->protocol == IPPROTO_UDP)
                        ctrl |= UDPTCP;
 
-               le = get_tx_le(sky2);
-               le->tx.csum.start = cpu_to_le16(hdr);
-               le->tx.csum.offset = cpu_to_le16(offset);
-               le->length = 0; /* initial checksum value */
-               le->ctrl = 1;   /* one packet */
-               le->opcode = OP_TCPLISW | HW_OWNER;
+               if (hdr != sky2->tx_csum_start || offset != sky2->tx_csum_offset) {
+                       sky2->tx_csum_start = hdr;
+                       sky2->tx_csum_offset = offset;
+
+                       le = get_tx_le(sky2);
+                       le->tx.csum.start = cpu_to_le16(hdr);
+                       le->tx.csum.offset = cpu_to_le16(offset);
+                       le->length = 0; /* initial checksum value */
+                       le->ctrl = 1;   /* one packet */
+                       le->opcode = OP_TCPLISW | HW_OWNER;
+               }
        }
 
        le = get_tx_le(sky2);

diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h
index bb92f69..fa8af9f 100644 (file)
--- a/drivers/net/sky2.h
+++ b/drivers/net/sky2.h
@@ -1843,6 +1843,8 @@ struct sky2_port {
        u32                  tx_addr64;
        u16                  tx_pending;
        u16                  tx_last_mss;
+       u16                  tx_csum_start;
+       u16                  tx_csum_offset;
 
        struct ring_info     *rx_ring ____cacheline_aligned_in_smp;
        struct sky2_rx_le    *rx_le;