[PATCH] x86_64: Implement evex512 version of memchr, rawmemchr and wmemchr
Noah Goldstein
goldstein.w.n@gmail.com
Thu Sep 29 04:07:15 GMT 2022
On Wed, Sep 28, 2022 at 8:43 PM Sunil Pandey <skpgkp2@gmail.com> wrote:
>
> On Thu, Sep 22, 2022 at 8:57 PM Sunil Pandey <skpgkp2@gmail.com> wrote:
> >
> > Microbenchmark data collected on: Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz
> >
> >
> > On Wed, Sep 21, 2022 at 5:50 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > >
> > > On Wed, Sep 21, 2022 at 5:27 PM Sunil K Pandey via Libc-alpha
> > > <libc-alpha@sourceware.org> wrote:
> > > >
> > > > This patch implements following evex512 version of string functions.
> > > > evex512 version takes up to 30% less cycle as compared to evex,
> > > > depending on length and alignment.
> > >
> > > Please attach benchmark numbers.
> > > >
> > > > - memchr function using 512 bit vectors.
> > > > - rawmemchr function using 512 bit vectors.
> > > > - wmemchr function using 512 bit vectors.
> > > >
> > > > Code size data:
> > > >
> > > > memchr-evex.o 762 byte
> > > > memchr-evex512.o 570 byte (-25%)
> > > >
> > > > rawmemchr-evex.o 461 byte
> > > > rawmemchr-evex512.o 413 byte (-10%)
> > > >
> > > > wmemchr-evex.o 794 byte
> > > > wmemchr-evex512.o 568 byte (-28%)
> > > >
> > > > Placeholder function, not used by any processor at the moment.
> > > > ---
> > > > sysdeps/x86_64/multiarch/Makefile | 3 +
> > > > sysdeps/x86_64/multiarch/ifunc-impl-list.c | 15 +
> > > > sysdeps/x86_64/multiarch/memchr-evex-base.S | 306 +++++++++++++++++++
> > > > sysdeps/x86_64/multiarch/memchr-evex512.S | 7 +
> > > > sysdeps/x86_64/multiarch/rawmemchr-evex512.S | 7 +
> > > > sysdeps/x86_64/multiarch/wmemchr-evex512.S | 8 +
> > > > 6 files changed, 346 insertions(+)
> > > > create mode 100644 sysdeps/x86_64/multiarch/memchr-evex-base.S
> > > > create mode 100644 sysdeps/x86_64/multiarch/memchr-evex512.S
> > > > create mode 100644 sysdeps/x86_64/multiarch/rawmemchr-evex512.S
> > > > create mode 100644 sysdeps/x86_64/multiarch/wmemchr-evex512.S
> > > >
> > > > diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> > > > index df4601c294..e974b1ad97 100644
> > > > --- a/sysdeps/x86_64/multiarch/Makefile
> > > > +++ b/sysdeps/x86_64/multiarch/Makefile
> > > > @@ -4,6 +4,7 @@ sysdep_routines += \
> > > > memchr-avx2 \
> > > > memchr-avx2-rtm \
> > > > memchr-evex \
> > > > + memchr-evex512 \
> > > > memchr-evex-rtm \
> > > > memchr-sse2 \
> > > > memcmp-avx2-movbe \
> > > > @@ -36,6 +37,7 @@ sysdep_routines += \
> > > > rawmemchr-avx2 \
> > > > rawmemchr-avx2-rtm \
> > > > rawmemchr-evex \
> > > > + rawmemchr-evex512 \
> > > > rawmemchr-evex-rtm \
> > > > rawmemchr-sse2 \
> > > > stpcpy-avx2 \
> > > > @@ -156,6 +158,7 @@ sysdep_routines += \
> > > > wmemchr-avx2 \
> > > > wmemchr-avx2-rtm \
> > > > wmemchr-evex \
> > > > + wmemchr-evex512 \
> > > > wmemchr-evex-rtm \
> > > > wmemchr-sse2 \
> > > > wmemcmp-avx2-movbe \
> > > > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > > > index a71444eccb..17f770318d 100644
> > > > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > > > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > > > @@ -63,6 +63,11 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > > > && CPU_FEATURE_USABLE (AVX512BW)
> > > > && CPU_FEATURE_USABLE (BMI2)),
> > > > __memchr_evex)
> > > > + X86_IFUNC_IMPL_ADD_V4 (array, i, memchr,
> > > > + (CPU_FEATURE_USABLE (AVX512VL)
> > > > + && CPU_FEATURE_USABLE (AVX512BW)
> > > > + && CPU_FEATURE_USABLE (BMI2)),
> > > > + __memchr_evex512)
> > > > X86_IFUNC_IMPL_ADD_V4 (array, i, memchr,
> > > > (CPU_FEATURE_USABLE (AVX512VL)
> > > > && CPU_FEATURE_USABLE (AVX512BW)
> > > > @@ -329,6 +334,11 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > > > && CPU_FEATURE_USABLE (AVX512BW)
> > > > && CPU_FEATURE_USABLE (BMI2)),
> > > > __rawmemchr_evex)
> > > > + X86_IFUNC_IMPL_ADD_V4 (array, i, rawmemchr,
> > > > + (CPU_FEATURE_USABLE (AVX512VL)
> > > > + && CPU_FEATURE_USABLE (AVX512BW)
> > > > + && CPU_FEATURE_USABLE (BMI2)),
> > > > + __rawmemchr_evex512)
> > > > X86_IFUNC_IMPL_ADD_V4 (array, i, rawmemchr,
> > > > (CPU_FEATURE_USABLE (AVX512VL)
> > > > && CPU_FEATURE_USABLE (AVX512BW)
> > > > @@ -903,6 +913,11 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > > > && CPU_FEATURE_USABLE (AVX512BW)
> > > > && CPU_FEATURE_USABLE (BMI2)),
> > > > __wmemchr_evex)
> > > > + X86_IFUNC_IMPL_ADD_V4 (array, i, wmemchr,
> > > > + (CPU_FEATURE_USABLE (AVX512VL)
> > > > + && CPU_FEATURE_USABLE (AVX512BW)
> > > > + && CPU_FEATURE_USABLE (BMI2)),
> > > > + __wmemchr_evex512)
> > > > X86_IFUNC_IMPL_ADD_V4 (array, i, wmemchr,
> > > > (CPU_FEATURE_USABLE (AVX512VL)
> > > > && CPU_FEATURE_USABLE (AVX512BW)
> > > > diff --git a/sysdeps/x86_64/multiarch/memchr-evex-base.S b/sysdeps/x86_64/multiarch/memchr-evex-base.S
> > > > new file mode 100644
> > > > index 0000000000..524f0809b5
> > > > --- /dev/null
> > > > +++ b/sysdeps/x86_64/multiarch/memchr-evex-base.S
> > > > @@ -0,0 +1,306 @@
> > > > +/* Placeholder function, not used by any processor at the moment.
> > > > + Copyright (C) 2022 Free Software Foundation, Inc.
> > > > + This file is part of the GNU C Library.
> > > > +
> > > > + The GNU C Library is free software; you can redistribute it and/or
> > > > + modify it under the terms of the GNU Lesser General Public
> > > > + License as published by the Free Software Foundation; either
> > > > + version 2.1 of the License, or (at your option) any later version.
> > > > +
> > > > + The GNU C Library is distributed in the hope that it will be useful,
> > > > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > > > + Lesser General Public License for more details.
> > > > +
> > > > + You should have received a copy of the GNU Lesser General Public
> > > > + License along with the GNU C Library; if not, see
> > > > + <https://www.gnu.org/licenses/>. */
> > > > +
> > > > +/* UNUSED. Exists purely as reference implementation. */
> > > > +
> > > > +#include <isa-level.h>
> > > > +
> > > > +#if ISA_SHOULD_BUILD (4)
> > > > +
> > > > +# include <sysdep.h>
> > > > +
> > > > +# ifdef USE_AS_WMEMCHR
> > > > +# define CHAR_SIZE 4
> > > > +# define VPBROADCAST vpbroadcastd
> > > > +# define VPCMP vpcmpd
> > > > +# else
> > > > +# define CHAR_SIZE 1
> > > > +# define VPBROADCAST vpbroadcastb
> > > > +# define VPCMP vpcmpb
> > > > +# endif
> > > > +
> > > > +# define PAGE_SIZE 4096
> > > > +# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
> > > > +# define XMM1 xmm17
> > > > +
> > > > +# if VEC_SIZE == 64
> > > > +# define KMOV kmovq
> > > > +# define KOR korq
> > > > +# define KORTEST kortestq
> > > > +# define RAX rax
> > > > +# define RCX rcx
> > > > +# define SHR shrq
> > > > +# define SARX sarxq
> > > > +# define TEXTSUFFIX evex512
> > > > +# define VMM0 zmm16
> > > > +# elif VEC_SIZE == 32
> > > > +/* Currently Unused. */
> > > > +# define KMOV kmovd
> > > > +# define KOR kord
> > > > +# define KORTEST kortestd
> > > > +# define RAX eax
> > > > +# define RCX ecx
> > > > +# define SHR shrl
> > > > +# define SARX sarxl
> > > > +# define TEXTSUFFIX evex256
> > > > +# define VMM0 ymm16
> > > > +# endif
> > > > +
> > > > + .section .text.TEXTSUFFIX, "ax", @progbits
> > > > +/* Aligning entry point to 64 byte, provides better performance for
> > > > + one vector length string. */
> > > > +ENTRY_P2ALIGN (MEMCHR, 6)
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + /* Check for zero length. */
> > > > + test %RDX_LP, %RDX_LP
> > > > + jz L(zero)
> > > > +
> > > > +# ifdef __ILP32__
> > > > + /* Clear the upper 32 bits. */
> > > > + movl %edx, %edx
> > > > +# endif
> > > > +# endif
> > > > +
> > > > + /* Broadcast CHAR to VMM0. */
> > > > + VPBROADCAST %esi, %VMM0
> > > > + movl %edi, %eax
> > > > + andl $(PAGE_SIZE - 1), %eax
> > > > + cmpl $(PAGE_SIZE - VEC_SIZE), %eax
> > > > + ja L(page_cross)
> > > > +
> > > > + /* Compare [w]char for null, mask bit will be set for match. */
> > > > + VPCMP $0, (%rdi), %VMM0, %k0
> > > > +
> > > > + KMOV %k0, %RAX
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + bsf %RAX, %RCX
> > > > + jz L(align_more)
> > > > + xor %eax, %eax
> > > > +# ifdef USE_AS_WMEMCHR
> > > > + leaq (%rdi, %rcx, CHAR_SIZE), %rdi
> > > > +# else
> > > > + addq %rcx, %rdi
> > > > +# endif
> > > > + cmp %rcx, %rdx
> > > > + cmova %rdi, %rax
> > > > +# else
> > > > + bsf %RAX, %RAX
> > > > + jz L(align_more)
> > > > + add %rdi, %rax
> > > > +# endif
> > > > + ret
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > +L(zero):
> > > > + xorl %eax, %eax
> > > > + ret
> > > > +# endif
> > > > +
> > > > + .p2align 5,,5
> > > > +L(page_cross):
> > > > + movq %rdi, %rcx
> > > > + andq $-VEC_SIZE, %rcx
> > > > +
> > > > + VPCMP $0, (%rcx), %VMM0, %k0
> > > > + KMOV %k0, %RCX
> > > > + SARX %RAX, %RCX, %RAX
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + bsf %RAX, %RCX
> > > > + jz L(align_more)
> > > > + xor %eax, %eax
> > > > +# ifdef USE_AS_WMEMCHR
> > > > + leaq (%rdi, %rcx, CHAR_SIZE), %rdi
> > > > +# else
> > > > + addq %rcx, %rdi
> > > > +# endif
> > > > + cmp %rcx, %rdx
> > > > + cmovae %rdi, %rax
> > > > +
> > > > +# else
> > > > + bsf %rax, %rax
> > > > + jz L(align_more)
> > > > + add %rdi, %rax
> > > > +# endif
> > > > + ret
> > > > +
> > > > +L(ret_vec_x2):
> > > > + subq $-VEC_SIZE, %rdi
> > > > +L(ret_vec_x1):
> > > > + bsf %RAX, %RAX
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + jz L(zero)
> > > > + cmp %rax, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +# ifdef USE_AS_WMEMCHR
> > > > + leaq (%rdi, %rax, CHAR_SIZE), %rax
> > > > +# else
> > > > + add %rdi, %rax
> > > > +# endif
> > > > + ret
> > > > +
> > > > + .p2align 5,,10
> > > > +L(align_more):
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + xor %eax, %eax
> > > > + subq %rdi, %rax
> > > > +# endif
> > > > +
> > > > + subq $-VEC_SIZE, %rdi
> > > > + /* Align rdi to VEC_SIZE. */
> > > > + andq $-VEC_SIZE, %rdi
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + addq %rdi, %rax
> > > > +# ifdef USE_AS_WMEMCHR
> > > > + sarl $2, %eax
> > > > +# endif
> > > > + subq %rax, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + /* Loop unroll 4 times for 4 vector loop. */
> > > > + VPCMP $0, (%rdi), %VMM0, %k0
> > > > +
> > > > + KMOV %k0, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x1)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + VPCMP $0, VEC_SIZE(%rdi), %VMM0, %k0
> > > > +
> > > > + KMOV %k0, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x2)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + VPCMP $0, (VEC_SIZE * 2)(%rdi), %VMM0, %k0
> > > > +
> > > > + KMOV %k0, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x3)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + VPCMP $0, (VEC_SIZE * 3)(%rdi), %VMM0, %k0
> > > > +
> > > > + KMOV %k0, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x4)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > + /* Save pointer to find alignment adjustment. */
> > > > + movq %rdi, %rax
> > > > +# endif
> > > > + /* Align address to VEC_SIZE * 4 for loop. */
> > > > + andq $-(VEC_SIZE * 4), %rdi
> > > > +
> > > > + /* Add alignment difference to rdx. */
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq %rdi, %rax
> > > > +# ifdef USE_AS_WMEMCHR
> > > > + SHR $2, %RAX
> > > > +# endif
> > > > + addq %rax, %rdx
> > > > + jmp L(loop_entry)
> > > > +# endif
> > > > +
> > > > + /* 4 vector loop. */
> > > > + .p2align 5,,11
> > > > +L(loop):
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $(CHAR_PER_VEC * 4), %rdx
> > > > + jbe L(zero)
> > > > +L(loop_entry):
> > > > +# endif
> > > > + VPCMP $0, (VEC_SIZE * 4)(%rdi), %VMM0, %k1
> > > > + VPCMP $0, (VEC_SIZE * 5)(%rdi), %VMM0, %k2
> > > > + VPCMP $0, (VEC_SIZE * 6)(%rdi), %VMM0, %k3
> > > > + VPCMP $0, (VEC_SIZE * 7)(%rdi), %VMM0, %k4
> > > > + KOR %k1, %k2, %k5
> > > > + KOR %k3, %k4, %k6
> > > > +
> > > > + subq $-(VEC_SIZE * 4), %rdi
> > > > + KORTEST %k5, %k6
> > > > + jz L(loop)
> > > > +
> > > > + KMOV %k1, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x1)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + KMOV %k2, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x2)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + KMOV %k3, %RAX
> > > > + test %RAX, %RAX
> > > > + jnz L(ret_vec_x3)
> > > > +
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + subq $CHAR_PER_VEC, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > +
> > > > + /* At this point null [w]char must be in the fourth vector so no
> > > > + need to check. */
> > > > + KMOV %k4, %RAX
> > > > +
> > > > +L(ret_vec_x4):
> > > > + bsf %RAX, %RAX
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + cmp %rax, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > + leaq (VEC_SIZE * 3)(%rdi, %rax, CHAR_SIZE), %rax
> > > > + ret
> > > > +
> > > > + .p2align 5,,5
> > > > +L(ret_vec_x3):
> > > > + bsf %RAX, %RAX
> > > > +# ifndef USE_AS_RAWMEMCHR
> > > > + cmp %rax, %rdx
> > > > + jbe L(zero)
> > > > +# endif
> > > > + leaq (VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %rax
> > > > + ret
> > > > +
> > > > +END (MEMCHR)
> > > > +#endif
> > > > diff --git a/sysdeps/x86_64/multiarch/memchr-evex512.S b/sysdeps/x86_64/multiarch/memchr-evex512.S
> > > > new file mode 100644
> > > > index 0000000000..47349d817a
> > > > --- /dev/null
> > > > +++ b/sysdeps/x86_64/multiarch/memchr-evex512.S
> > > > @@ -0,0 +1,7 @@
> > > > +# ifndef MEMCHR
> > > > +# define MEMCHR __memchr_evex512
> > > > +# endif
> > > > +
> > > > +#define VEC_SIZE 64
> > > > +
> > > > +#include "memchr-evex-base.S"
> > > > diff --git a/sysdeps/x86_64/multiarch/rawmemchr-evex512.S b/sysdeps/x86_64/multiarch/rawmemchr-evex512.S
> > > > new file mode 100644
> > > > index 0000000000..302d3cb055
> > > > --- /dev/null
> > > > +++ b/sysdeps/x86_64/multiarch/rawmemchr-evex512.S
> > > > @@ -0,0 +1,7 @@
> > > > +#ifndef RAWMEMCHR
> > > > +# define RAWMEMCHR __rawmemchr_evex512
> > > > +#endif
> > > > +#define USE_AS_RAWMEMCHR 1
> > > > +#define MEMCHR RAWMEMCHR
> > > > +
> > > > +#include "memchr-evex512.S"
> > > > diff --git a/sysdeps/x86_64/multiarch/wmemchr-evex512.S b/sysdeps/x86_64/multiarch/wmemchr-evex512.S
> > > > new file mode 100644
> > > > index 0000000000..f45ed1db75
> > > > --- /dev/null
> > > > +++ b/sysdeps/x86_64/multiarch/wmemchr-evex512.S
> > > > @@ -0,0 +1,8 @@
> > > > +#ifndef WMEMCHR
> > > > +# define WMEMCHR __wmemchr_evex512
> > > > +#endif
> > > > +
> > > > +#define MEMCHR WMEMCHR
> > > > +#define USE_AS_WMEMCHR 1
> > > > +
> > > > +#include "memchr-evex512.S"
> > > > --
> > > > 2.36.1
> > > >
>
> ping
see my reply to strrchr.
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