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authorEric Dumazet <dada1@cosmosbay.com>2008-11-24 02:24:32 -0500
committerDavid S. Miller <davem@davemloft.net>2008-11-24 02:24:32 -0500
commit1f87e235e6fb92c2968b52b9191de04f1aff8e77 (patch)
treeab774d239c61b6c206ef07398828533cdd01915e /net/ethernet
parent70eb1bfd52e97120eddf9b5aaabfe1ecdf4eb663 (diff)
eth: Declare an optimized compare_ether_addr_64bits() function
Linus mentioned we could try to perform long word operations, even on potentially unaligned addresses, on x86 at least. David mentioned the HAVE_EFFICIENT_UNALIGNED_ACCESS test to handle this on all arches that have efficient unailgned accesses. I tried this idea and got nice assembly on 32 bits: 158: 33 82 38 01 00 00 xor 0x138(%edx),%eax 15e: 33 8a 34 01 00 00 xor 0x134(%edx),%ecx 164: c1 e0 10 shl $0x10,%eax 167: 09 c1 or %eax,%ecx 169: 74 0b je 176 <eth_type_trans+0x87> And very nice assembly on 64 bits of course (one xor, one shl) Nice oprofile improvement in eth_type_trans(), 0.17 % instead of 0.41 %, expected since we remove 8 instructions on a fast path. This patch implements a compare_ether_addr_64bits() function, that uses the CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS ifdef to efficiently perform the 6 bytes comparison on all capable arches. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ethernet')
-rw-r--r--net/ethernet/eth.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index a87a171d9914..280352aba403 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -165,8 +165,8 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
165 skb_pull(skb, ETH_HLEN); 165 skb_pull(skb, ETH_HLEN);
166 eth = eth_hdr(skb); 166 eth = eth_hdr(skb);
167 167
168 if (is_multicast_ether_addr(eth->h_dest)) { 168 if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
169 if (!compare_ether_addr(eth->h_dest, dev->broadcast)) 169 if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast))
170 skb->pkt_type = PACKET_BROADCAST; 170 skb->pkt_type = PACKET_BROADCAST;
171 else 171 else
172 skb->pkt_type = PACKET_MULTICAST; 172 skb->pkt_type = PACKET_MULTICAST;
@@ -181,7 +181,7 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
181 */ 181 */
182 182
183 else if (1 /*dev->flags&IFF_PROMISC */ ) { 183 else if (1 /*dev->flags&IFF_PROMISC */ ) {
184 if (unlikely(compare_ether_addr(eth->h_dest, dev->dev_addr))) 184 if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr)))
185 skb->pkt_type = PACKET_OTHERHOST; 185 skb->pkt_type = PACKET_OTHERHOST;
186 } 186 }
187 187