From: Robin Murphy <robin.murphy@arm.com>
To: will@kernel.org, catalin.marinas@arm.com
Cc: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: csum: Optimise IPv6 header checksum
Date: Mon, 20 Jan 2020 18:52:29 +0000 [thread overview]
Message-ID: <3a723a4b08938154c37febe2504f029c4480e53c.1579546194.git.robin.murphy@arm.com> (raw)
Throwing our __uint128_t idioms at csum_ipv6_magic() makes it
about 1.3x-2x faster across a range of microarchitecture/compiler
combinations. Not much in absolute terms, but every little helps.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
Before I move on, this seemed like it might be worth touching as well,
comparing what other architectures do.
arch/arm64/include/asm/checksum.h | 7 ++++++-
arch/arm64/lib/csum.c | 27 +++++++++++++++++++++++++++
2 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/checksum.h b/arch/arm64/include/asm/checksum.h
index 8d2a7de39744..b6f7bc6da5fb 100644
--- a/arch/arm64/include/asm/checksum.h
+++ b/arch/arm64/include/asm/checksum.h
@@ -5,7 +5,12 @@
#ifndef __ASM_CHECKSUM_H
#define __ASM_CHECKSUM_H
-#include <linux/types.h>
+#include <linux/in6.h>
+
+#define _HAVE_ARCH_IPV6_CSUM
+__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ __u32 len, __u8 proto, __wsum sum);
static inline __sum16 csum_fold(__wsum csum)
{
diff --git a/arch/arm64/lib/csum.c b/arch/arm64/lib/csum.c
index 847eb725ce09..4a522e45f23b 100644
--- a/arch/arm64/lib/csum.c
+++ b/arch/arm64/lib/csum.c
@@ -121,3 +121,30 @@ unsigned int do_csum(const unsigned char *buff, int len)
return sum >> 16;
}
+
+__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ __u32 len, __u8 proto, __wsum csum)
+{
+ __uint128_t src, dst;
+ u64 sum = (__force u64)csum;
+
+ src = *(const __uint128_t *)saddr->s6_addr;
+ dst = *(const __uint128_t *)daddr->s6_addr;
+
+ sum += (__force u32)htonl(len);
+#ifdef __LITTLE_ENDIAN
+ sum += (u32)proto << 24;
+#else
+ sum += proto;
+#endif
+ src += (src >> 64) | (src << 64);
+ dst += (dst >> 64) | (dst << 64);
+
+ sum = accumulate(sum, src >> 64);
+ sum = accumulate(sum, dst >> 64);
+
+ sum += ((sum >> 32) | (sum << 32));
+ return csum_fold((__force __wsum)(sum >> 32));
+}
+EXPORT_SYMBOL(csum_ipv6_magic);
--
2.23.0.dirty
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next reply other threads:[~2020-01-20 18:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-20 18:52 Robin Murphy [this message]
2020-01-21 10:34 ` [PATCH] arm64: csum: Optimise IPv6 header checksum Will Deacon
2020-02-03 9:29 ` Shaokun Zhang
2020-02-11 8:35 ` Chen Zhou
2020-03-09 18:09 ` Catalin Marinas
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