From aa4b9f533ed5a22952e038b9fac2447ccc682124 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 8 Feb 2009 18:00:37 +0000 Subject: 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 Signed-off-by: David S. Miller --- include/linux/etherdevice.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'include/linux/etherdevice.h') 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 */ -- cgit v1.2.3-59-g8ed1b