From: Lingyan Huang <huanglingyan2@huawei.com> To: <linux-arm-kernel@lists.infradead.org> Cc: Lingyan Huang <huanglingyan2@huawei.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Will Deacon <will.deacon@arm.com>, Catalin Marinas <catalin.marinas@arm.com> Subject: [PATCH v3] arm64: lib: accelerate do_csum with NEON instruction Date: Sun, 6 Jan 2019 09:55:29 +0800 Message-ID: <1546739729-17234-1-git-send-email-huanglingyan2@huawei.com> (raw) Function do_csum() in lib/checksum.c is used to compute checksum, which is turned out to be slowly and costs a lot of resources. Let's use neon instructions to accelerate the checksum computation for arm64. ------ V2 ==> V3: only modify the arm64 codes instead of modifying headers under asm-generic and code in lib/checksum.c. ------ ------ V1 ==> V2: Change NEON assembly code to NEON intrinsic code which is built on top of arm_neon.h to avoid dropping into assembly. ------ Here is the comparison results of function ip_compute_csum() between general do_csum() and neon instruction do_csum(). The test platform is HUAWEI 1620 server with TAISHAN cores. len(1000cycle) general(ns) do_csum_neon(ns) 64B: 58060 59460 128B: 82930 83930 256B: 132480 73570 512B: 230100 86230 1024B: 426600 98200 Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Lingyan Huang <huanglingyan2@huawei.com> --- arch/arm64/include/asm/checksum.h | 5 ++ arch/arm64/lib/Makefile | 8 +-- arch/arm64/lib/checksum.c | 26 ++++++++ arch/arm64/lib/do_csum.c | 136 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 171 insertions(+), 4 deletions(-) create mode 100644 arch/arm64/lib/checksum.c create mode 100644 arch/arm64/lib/do_csum.c diff --git a/arch/arm64/include/asm/checksum.h b/arch/arm64/include/asm/checksum.h index 0b6f5a7..7acd713 100644 --- a/arch/arm64/include/asm/checksum.h +++ b/arch/arm64/include/asm/checksum.h @@ -26,6 +26,10 @@ static inline __sum16 csum_fold(__wsum csum) } #define csum_fold csum_fold +#define do_csum do_csum +unsigned int do_csum(const unsigned char *buff, int len); +extern unsigned int do_csum_arm(const unsigned char *buff, int len); + static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) { __uint128_t tmp; @@ -46,6 +50,7 @@ static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) } #define ip_fast_csum ip_fast_csum + #include <asm-generic/checksum.h> #endif /* __ASM_CHECKSUM_H */ diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index 5540a16..c0b5b8c 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -3,12 +3,12 @@ lib-y := clear_user.o delay.o copy_from_user.o \ copy_to_user.o copy_in_user.o copy_page.o \ clear_page.o memchr.o memcpy.o memmove.o memset.o \ memcmp.o strcmp.o strncmp.o strlen.o strnlen.o \ - strchr.o strrchr.o tishift.o + strchr.o strrchr.o tishift.o checksum.o ifeq ($(CONFIG_KERNEL_MODE_NEON), y) -obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o -CFLAGS_REMOVE_xor-neon.o += -mgeneral-regs-only -CFLAGS_xor-neon.o += -ffreestanding +obj-y += do_csum.o +CFLAGS_REMOVE_do_csum.o += -mgeneral-regs-only +CFLAGS_do_csum.o += -ffreestanding endif # Tell the compiler to treat all general purpose registers (with the diff --git a/arch/arm64/lib/checksum.c b/arch/arm64/lib/checksum.c new file mode 100644 index 0000000..15a31bb --- /dev/null +++ b/arch/arm64/lib/checksum.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * + * Authors: Lingyan Huang <huanglingyan2@huawei.com> + * Copyright (C) 2018 Hisilicon, Inc. All Rights Reserved. + * + * Generic C or neon implementation of do_csum operations. + * Choose faster neon instructions when NEON is supported. + * + */ + +#include <asm/neon.h> +#include <asm/simd.h> +#include <asm/checksum.h> + +#define CSUM_NEON_THRESHOLD 128 + +unsigned int do_csum(const unsigned char *buff, int len) +{ +#ifdef CONFIG_KERNEL_MODE_NEON + if (len >= CSUM_NEON_THRESHOLD) + return do_csum_arm(buff, len); +#endif /* CONFIG_KERNEL_MODE_NEON */ +#undef do_csum + return 0; +} diff --git a/arch/arm64/lib/do_csum.c b/arch/arm64/lib/do_csum.c new file mode 100644 index 0000000..893583f --- /dev/null +++ b/arch/arm64/lib/do_csum.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Authors: Lingyan Huang <huanglingyan2@huawei.com> + * Copyright (C) 2018 Hisilicon, Inc. All Rights Reserved. + * + * Generic C or neon implementation of do_csum operations. + * Choose faster neon instructions when NEON is supported. + * + */ + +#include <asm/neon.h> +#include <asm/simd.h> +#include <asm/checksum.h> +#include <asm/byteorder.h> +#include <asm/neon-intrinsics.h> + +#define CSUM_NEON_THRESHOLD 128 +#ifdef CONFIG_KERNEL_MODE_NEON +static inline u32 from64to16(u64 x) +{ + /* add up 32-bit and 32-bit for 32+c bit */ + x = (x & 0xffffffff) + (x >> 32); + /* add up carry.. */ + x = (x & 0xffffffff) + (x >> 32); + /* add up 16-bit and 16-bit for 16+c bit */ + x = ((u32)x & 0xffff) + ((u32)x >> 16); + /* add up carry.. */ + x = ((u32)x & 0xffff) + ((u32)x >> 16); + return x; +} + +unsigned int do_csum_neon(const unsigned char *buff, int len) +{ + unsigned int odd, count; + uint64_t result = 0; + unsigned int count64; + uint32x4_t vzero = (uint32x4_t){0, 0, 0, 0}; + + register uint32x4_t v0, v1, v2, v3; + + if (unlikely(len <= 0)) + return result; + + odd = 1 & (unsigned long)buff; + if (unlikely(odd)) { + result = *buff; + len--; + buff++; + } + + count = len >> 1; + if (count) { + if (2 & (unsigned long)buff) { + result += *(unsigned short *)buff; + count--; + len -= 2; + buff += 2; + } + count >>= 1; /* nr of 32-bit words.. */ + if (count) { + if (4 & (unsigned long)buff) { + result += *(unsigned int *)buff; + count--; + len -= 4; + buff += 4; + } + count >>= 1; /* nr of 64-bit words.. */ + + v0 = vzero; + v1 = vzero; + v2 = vzero; + v3 = vzero; + + count64 = count >> 3; /* compute 64 Byte circle */ + while (count64) { + v0 = vpadalq_u16(v0, + vld1q_u16((uint16_t *)buff + 0)); + v1 = vpadalq_u16(v1, + vld1q_u16((uint16_t *)buff + 8)); + v2 = vpadalq_u16(v2, + vld1q_u16((uint16_t *)buff + 16)); + v3 = vpadalq_u16(v3, + vld1q_u16((uint16_t *)buff + 24)); + buff += 64; + count64--; + } + v0 = vaddq_u32(v0, v1); + v2 = vaddq_u32(v2, v3); + v0 = vaddq_u32(v0, v2); + + count %= 8; + while (count >= 2) { /* compute 16 byte circle */ + v0 = vpadalq_u16(v0, + vld1q_u16((uint16_t *)buff + 0)); + buff += 16; + count -= 2; + } + + result += vgetq_lane_u32(v0, 0); + result += vgetq_lane_u32(v0, 1); + result += vgetq_lane_u32(v0, 2); + result += vgetq_lane_u32(v0, 3); + if (count & 1) { + result += *(unsigned long long *)buff; + buff += 8; + } + if (len & 4) { + result += *(unsigned int *)buff; + buff += 4; + } + } + if (len & 2) { + result += *(unsigned short *)buff; + buff += 2; + } + } + if (len & 1) + result += *buff; + result = from64to16(result); + if (odd) + result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); + return result; +} +#endif + + +unsigned int do_csum_arm(const unsigned char *buff, int len) +{ + unsigned int res; + + kernel_neon_begin(); + res = do_csum_neon(buff, len); + kernel_neon_end(); + return res; +} + -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply index Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-06 1:55 Lingyan Huang [this message] 2019-01-06 8:26 ` Ard Biesheuvel [not found] ` <9129b882-60f3-8046-0cb9-e0b2452a118d@huawei.com> 2019-01-08 13:54 ` Will Deacon 2019-01-09 2:03 ` huanglingyan (A) 2019-01-10 4:08 ` 胡海 2019-01-10 8:14 ` huanglingyan (A) 2019-01-16 16:46 ` Will Deacon 2019-01-18 1:07 ` huanglingyan (A) 2019-01-18 11:14 ` Ard Biesheuvel 2019-02-12 2:26 ` huanglingyan (A) 2019-02-12 7:07 ` Ard Biesheuvel 2019-02-13 8:42 ` huanglingyan (A) 2019-02-13 9:15 ` Ard Biesheuvel 2019-02-13 17:55 ` Ard Biesheuvel 2019-02-14 9:57 ` huanglingyan (A) 2019-02-18 8:49 ` huanglingyan (A) 2019-02-18 9:03 ` Ard Biesheuvel 2019-01-09 14:58 ` Dave Martin 2019-01-10 8:03 ` huanglingyan (A) 2019-01-10 13:53 ` Dave Martin [not found] <1f065749-6676-6489-14ae-fdcfeeb3389c@huawei.com> 2019-01-07 6:11 ` huanglingyan (A)
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