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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2009-02-08 18:00:37 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-02-08 20:22:18 -0800 |
| commit | aa4b9f533ed5a22952e038b9fac2447ccc682124 (patch) | |
| tree | 91722b13a63dcd0e49695388e633cfa91b856b80 /include/linux/etherdevice.h | |
| parent | 4ae5544f9a33e4ae306e337f96951eb3ff2df6d9 (diff) | |
| download | linux-aa4b9f533ed5a22952e038b9fac2447ccc682124.tar.gz linux-aa4b9f533ed5a22952e038b9fac2447ccc682124.tar.bz2 linux-aa4b9f533ed5a22952e038b9fac2447ccc682124.zip | |
gro: Optimise Ethernet header comparison
This patch optimises the Ethernet header comparison to use 2-byte
and 4-byte xors instead of memcmp. In order to facilitate this,
the actual comparison is now carried out by the callers of the
shared dev_gro_receive function.
This has a significant impact when receiving 1500B packets through
10GbE.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/etherdevice.h')
| -rw-r--r-- | include/linux/etherdevice.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 1cb0f0b90926..a1f17abba7dc 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -184,4 +184,25 @@ static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2], } #endif /* __KERNEL__ */ +/** + * compare_ether_header - Compare two Ethernet headers + * @a: Pointer to Ethernet header + * @b: Pointer to Ethernet header + * + * Compare two ethernet headers, returns 0 if equal. + * This assumes that the network header (i.e., IP header) is 4-byte + * aligned OR the platform can handle unaligned access. This is the + * case for all packets coming into netif_receive_skb or similar + * entry points. + */ + +static inline int compare_ether_header(const void *a, const void *b) +{ + u32 *a32 = (u32 *)((u8 *)a + 2); + u32 *b32 = (u32 *)((u8 *)b + 2); + + return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) | + (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]); +} + #endif /* _LINUX_ETHERDEVICE_H */ |