Messages in this thread Patch in this message | | | From | Bibo Mao <> | Subject | [PATCH] LoongArch: add checksum optimization for 64-bit system | Date | Tue, 7 Feb 2023 12:01:48 +0800 |
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loongArch platform is 64-bit system, which supports 8 bytes memory accessing, generic checksum function uses 4 byte memory access. This patch adds 8-bytes memory access optimization for checksum function on loongArch. And the code comes from arm64 system.
When network hw checksum is disabled, iperf performance improves about 10% with this patch.
Signed-off-by: Bibo Mao <maobibo@loongson.cn> --- arch/loongarch/include/asm/checksum.h | 50 +++++++++ arch/loongarch/lib/Makefile | 2 +- arch/loongarch/lib/csum.c | 142 ++++++++++++++++++++++++++ 3 files changed, 193 insertions(+), 1 deletion(-) create mode 100644 arch/loongarch/include/asm/checksum.h create mode 100644 arch/loongarch/lib/csum.c
diff --git a/arch/loongarch/include/asm/checksum.h b/arch/loongarch/include/asm/checksum.h new file mode 100644 index 000000000000..c9d5af206604 --- /dev/null +++ b/arch/loongarch/include/asm/checksum.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2016 ARM Ltd. + */ +#ifndef __ASM_CHECKSUM_H +#define __ASM_CHECKSUM_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) +{ + u32 sum = (__force u32)csum; + + sum += (sum >> 16) | (sum << 16); + return ~(__force __sum16)(sum >> 16); +} +#define csum_fold csum_fold + +static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) +{ + __uint128_t tmp; + u64 sum; + int n = ihl; /* we want it signed */ + + tmp = *(const __uint128_t *)iph; + iph += 16; + n -= 4; + tmp += ((tmp >> 64) | (tmp << 64)); + sum = tmp >> 64; + do { + sum += *(const u32 *)iph; + iph += 4; + } while (--n > 0); + + sum += ((sum >> 32) | (sum << 32)); + return csum_fold((__force __wsum)(sum >> 32)); +} +#define ip_fast_csum ip_fast_csum + +extern unsigned int do_csum(const unsigned char *buff, int len); +#define do_csum do_csum + +#include <asm-generic/checksum.h> + +#endif /* __ASM_CHECKSUM_H */ diff --git a/arch/loongarch/lib/Makefile b/arch/loongarch/lib/Makefile index 40bde632900f..6ba6df411f90 100644 --- a/arch/loongarch/lib/Makefile +++ b/arch/loongarch/lib/Makefile @@ -4,4 +4,4 @@ # lib-y += delay.o memset.o memcpy.o memmove.o \ - clear_user.o copy_user.o dump_tlb.o unaligned.o + clear_user.o copy_user.o dump_tlb.o unaligned.o csum.o diff --git a/arch/loongarch/lib/csum.c b/arch/loongarch/lib/csum.c new file mode 100644 index 000000000000..0f7e3a5ce96a --- /dev/null +++ b/arch/loongarch/lib/csum.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2019-2020 Arm Ltd. + +#include <linux/compiler.h> +#include <linux/kasan-checks.h> +#include <linux/kernel.h> + +#include <net/checksum.h> + +/* Looks dumb, but generates nice-ish code */ +static u64 accumulate(u64 sum, u64 data) +{ + __uint128_t tmp; + + tmp = (__uint128_t)sum + data; + return tmp + (tmp >> 64); +} + +/* + * We over-read the buffer and this makes KASAN unhappy. Instead, disable + * instrumentation and call kasan explicitly. + */ +unsigned int __no_sanitize_address do_csum(const unsigned char *buff, int len) +{ + unsigned int offset, shift, sum; + const u64 *ptr; + u64 data, sum64 = 0; + + if (unlikely(len == 0)) + return 0; + + offset = (unsigned long)buff & 7; + /* + * This is to all intents and purposes safe, since rounding down cannot + * result in a different page or cache line being accessed, and @buff + * should absolutely not be pointing to anything read-sensitive. We do, + * however, have to be careful not to piss off KASAN, which means using + * unchecked reads to accommodate the head and tail, for which we'll + * compensate with an explicit check up-front. + */ + kasan_check_read(buff, len); + ptr = (u64 *)(buff - offset); + len = len + offset - 8; + + /* + * Head: zero out any excess leading bytes. Shifting back by the same + * amount should be at least as fast as any other way of handling the + * odd/even alignment, and means we can ignore it until the very end. + */ + shift = offset * 8; + data = *ptr++; + data = (data >> shift) << shift; + + /* + * Body: straightforward aligned loads from here on (the paired loads + * underlying the quadword type still only need dword alignment). The + * main loop strictly excludes the tail, so the second loop will always + * run at least once. + */ + while (unlikely(len > 64)) { + __uint128_t tmp1, tmp2, tmp3, tmp4; + + tmp1 = *(__uint128_t *)ptr; + tmp2 = *(__uint128_t *)(ptr + 2); + tmp3 = *(__uint128_t *)(ptr + 4); + tmp4 = *(__uint128_t *)(ptr + 6); + + len -= 64; + ptr += 8; + + /* This is the "don't dump the carry flag into a GPR" idiom */ + tmp1 += (tmp1 >> 64) | (tmp1 << 64); + tmp2 += (tmp2 >> 64) | (tmp2 << 64); + tmp3 += (tmp3 >> 64) | (tmp3 << 64); + tmp4 += (tmp4 >> 64) | (tmp4 << 64); + tmp1 = ((tmp1 >> 64) << 64) | (tmp2 >> 64); + tmp1 += (tmp1 >> 64) | (tmp1 << 64); + tmp3 = ((tmp3 >> 64) << 64) | (tmp4 >> 64); + tmp3 += (tmp3 >> 64) | (tmp3 << 64); + tmp1 = ((tmp1 >> 64) << 64) | (tmp3 >> 64); + tmp1 += (tmp1 >> 64) | (tmp1 << 64); + tmp1 = ((tmp1 >> 64) << 64) | sum64; + tmp1 += (tmp1 >> 64) | (tmp1 << 64); + sum64 = tmp1 >> 64; + } + while (len > 8) { + __uint128_t tmp; + + sum64 = accumulate(sum64, data); + tmp = *(__uint128_t *)ptr; + + len -= 16; + ptr += 2; + + data = tmp >> 64; + sum64 = accumulate(sum64, tmp); + } + if (len > 0) { + sum64 = accumulate(sum64, data); + data = *ptr; + len -= 8; + } + /* + * Tail: zero any over-read bytes similarly to the head, again + * preserving odd/even alignment. + */ + shift = len * -8; + data = (data << shift) >> shift; + sum64 = accumulate(sum64, data); + + /* Finally, folding */ + sum64 += (sum64 >> 32) | (sum64 << 32); + sum = sum64 >> 32; + sum += (sum >> 16) | (sum << 16); + if (offset & 1) + return (u16)swab32(sum); + + 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); + sum += (u32)proto << 24; + 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); -- 2.27.0
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