From patchwork Tue Mar 24 14:03:16 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick McHardy X-Patchwork-Id: 24974 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 654C0DDF7F for ; Wed, 25 Mar 2009 01:05:46 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755034AbZCXODV (ORCPT ); Tue, 24 Mar 2009 10:03:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755207AbZCXODU (ORCPT ); Tue, 24 Mar 2009 10:03:20 -0400 Received: from stinky.trash.net ([213.144.137.162]:34743 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755732AbZCXODS (ORCPT ); Tue, 24 Mar 2009 10:03:18 -0400 Received: from x2.localnet (localhost [127.0.0.1]) by stinky.trash.net (Postfix) with ESMTP id 67CD3948A5; Tue, 24 Mar 2009 15:03:16 +0100 (MET) From: Patrick McHardy To: davem@davemloft.net Cc: netdev@vger.kernel.org, Patrick McHardy , netfilter-devel@vger.kernel.org Message-Id: <20090324140312.31401.89168.sendpatchset@x2.localnet> In-Reply-To: <20090324140302.31401.37732.sendpatchset@x2.localnet> References: <20090324140302.31401.37732.sendpatchset@x2.localnet> Subject: netfilter 07/41: arp_tables: unfold two critical loops in arp_packet_match() Date: Tue, 24 Mar 2009 15:03:16 +0100 (MET) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org commit ddc214c43a923e89741e04da2f10e3037a64e222 Author: Eric Dumazet Date: Wed Feb 18 17:47:50 2009 +0100 netfilter: arp_tables: unfold two critical loops in arp_packet_match() x86 and powerpc can perform long word accesses in an efficient maner. We can use this to unroll two loops in arp_packet_match(), to perform arithmetic on long words instead of bytes. This is a win on x86_64 for example. Signed-off-by: Eric Dumazet Signed-off-by: Patrick McHardy --- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 7ea88b6..b5db463 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -73,6 +73,36 @@ static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap, return (ret != 0); } +/* + * Unfortunatly, _b and _mask are not aligned to an int (or long int) + * Some arches dont care, unrolling the loop is a win on them. + */ +static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) +{ +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + const unsigned long *a = (const unsigned long *)_a; + const unsigned long *b = (const unsigned long *)_b; + const unsigned long *mask = (const unsigned long *)_mask; + unsigned long ret; + + ret = (a[0] ^ b[0]) & mask[0]; + if (IFNAMSIZ > sizeof(unsigned long)) + ret |= (a[1] ^ b[1]) & mask[1]; + if (IFNAMSIZ > 2 * sizeof(unsigned long)) + ret |= (a[2] ^ b[2]) & mask[2]; + if (IFNAMSIZ > 3 * sizeof(unsigned long)) + ret |= (a[3] ^ b[3]) & mask[3]; + BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); +#else + unsigned long ret = 0; + int i; + + for (i = 0; i < IFNAMSIZ; i++) + ret |= (_a[i] ^ _b[i]) & _mask[i]; +#endif + return ret; +} + /* Returns whether packet matches rule or not. */ static inline int arp_packet_match(const struct arphdr *arphdr, struct net_device *dev, @@ -83,7 +113,7 @@ static inline int arp_packet_match(const struct arphdr *arphdr, const char *arpptr = (char *)(arphdr + 1); const char *src_devaddr, *tgt_devaddr; __be32 src_ipaddr, tgt_ipaddr; - int i, ret; + long ret; #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg))) @@ -156,10 +186,7 @@ static inline int arp_packet_match(const struct arphdr *arphdr, } /* Look for ifname matches. */ - for (i = 0, ret = 0; i < IFNAMSIZ; i++) { - ret |= (indev[i] ^ arpinfo->iniface[i]) - & arpinfo->iniface_mask[i]; - } + ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask); if (FWINV(ret != 0, ARPT_INV_VIA_IN)) { dprintf("VIA in mismatch (%s vs %s).%s\n", @@ -168,10 +195,7 @@ static inline int arp_packet_match(const struct arphdr *arphdr, return 0; } - for (i = 0, ret = 0; i < IFNAMSIZ; i++) { - ret |= (outdev[i] ^ arpinfo->outiface[i]) - & arpinfo->outiface_mask[i]; - } + ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask); if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) { dprintf("VIA out mismatch (%s vs %s).%s\n", @@ -221,7 +245,7 @@ unsigned int arpt_do_table(struct sk_buff *skb, const struct net_device *out, struct xt_table *table) { - static const char nulldevname[IFNAMSIZ]; + static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); unsigned int verdict = NF_DROP; const struct arphdr *arp; bool hotdrop = false;