From: Will Deacon <will@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: zhangshaokun@hisilicon.com, catalin.marinas@arm.com,
linux-arm-kernel@lists.infradead.org, huanglingyan2@huawei.com
Subject: Re: [PATCH] arm64: csum: Optimise IPv6 header checksum
Date: Tue, 21 Jan 2020 10:34:21 +0000 [thread overview]
Message-ID: <20200121103421.GA11819@willie-the-truck> (raw)
In-Reply-To: <3a723a4b08938154c37febe2504f029c4480e53c.1579546194.git.robin.murphy@arm.com>
[+ Shaokun and Lingyan for review and testing feedback]
On Mon, Jan 20, 2020 at 06:52:29PM +0000, Robin Murphy wrote:
> 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 prev parent reply other threads:[~2020-01-21 10:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-20 18:52 [PATCH] arm64: csum: Optimise IPv6 header checksum Robin Murphy
2020-01-21 10:34 ` Will Deacon [this message]
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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