[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>

2 files changed, 13 insertions, 6 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index fe60f0462c97..eafb6327d68f 100644
--- 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 bb92f694247f..fa8af9f503e4 100644
--- 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;