From: Noah Goldstein <goldstein.w.n@gmail.com>
To: libc-alpha@sourceware.org
Subject: [PATCH v1] x86: Improve vec generation in memset-vec-unaligned-erms.S
Date: Sat, 5 Feb 2022 16:42:01 -0600 [thread overview]
Message-ID: <20220205224201.1166468-1-goldstein.w.n@gmail.com> (raw)
No bug.
Split vec generation into multiple steps. This allows the
broadcast in AVX2 to use 'xmm' registers for the L(less_vec)
case. This saves an expensive lane-cross instruction and removes
the need for 'vzeroupper'.
For SSE2 replace 2x 'punpck' instructions with zero-idiom 'pxor' for
byte broadcast.
Results for memset-avx2 small (geomean of N = 20 benchset runs).
size, New Time, Old Time, New / Old
1, 5.074, 4.399, 0.867
2, 4.433, 4.411, 0.995
4, 4.487, 4.415, 0.984
8, 4.454, 4.396, 0.987
16, 4.502, 4.443, 0.987
All relevant string/wcsmbs tests are passing.
---
sysdeps/x86_64/memset.S | 21 ++-
.../multiarch/memset-avx2-unaligned-erms.S | 18 +-
.../multiarch/memset-avx512-unaligned-erms.S | 18 +-
.../multiarch/memset-evex-unaligned-erms.S | 18 +-
.../multiarch/memset-vec-unaligned-erms.S | 163 +++++++++++-------
5 files changed, 151 insertions(+), 87 deletions(-)
diff --git a/sysdeps/x86_64/memset.S b/sysdeps/x86_64/memset.S
index 65c09bd0ac..ccf036be53 100644
--- a/sysdeps/x86_64/memset.S
+++ b/sysdeps/x86_64/memset.S
@@ -28,17 +28,22 @@
#define VMOVU movups
#define VMOVA movaps
-#define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+# define MEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
movd d, %xmm0; \
- movq r, %rax; \
- punpcklbw %xmm0, %xmm0; \
- punpcklwd %xmm0, %xmm0; \
- pshufd $0, %xmm0, %xmm0
+ pxor %xmm1, %xmm1; \
+ pshufb %xmm1, %xmm0; \
+ movq r, %rax
-#define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+# define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
movd d, %xmm0; \
- movq r, %rax; \
- pshufd $0, %xmm0, %xmm0
+ pshufd $0, %xmm0, %xmm0; \
+ movq r, %rax
+
+# define MEMSET_VDUP_TO_VEC0_HIGH()
+# define MEMSET_VDUP_TO_VEC0_LOW()
+
+# define WMEMSET_VDUP_TO_VEC0_HIGH()
+# define WMEMSET_VDUP_TO_VEC0_LOW()
#define SECTION(p) p
diff --git a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
index 1af668af0a..c0bf2875d0 100644
--- a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
@@ -10,15 +10,18 @@
# define VMOVU vmovdqu
# define VMOVA vmovdqa
-# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+# define MEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
vmovd d, %xmm0; \
- movq r, %rax; \
- vpbroadcastb %xmm0, %ymm0
+ movq r, %rax;
-# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
- vmovd d, %xmm0; \
- movq r, %rax; \
- vpbroadcastd %xmm0, %ymm0
+# define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
+ MEMSET_SET_VEC0_AND_SET_RETURN(d, r)
+
+# define MEMSET_VDUP_TO_VEC0_HIGH() vpbroadcastb %xmm0, %ymm0
+# define MEMSET_VDUP_TO_VEC0_LOW() vpbroadcastb %xmm0, %xmm0
+
+# define WMEMSET_VDUP_TO_VEC0_HIGH() vpbroadcastd %xmm0, %ymm0
+# define WMEMSET_VDUP_TO_VEC0_LOW() vpbroadcastd %xmm0, %xmm0
# ifndef SECTION
# define SECTION(p) p##.avx
@@ -30,5 +33,6 @@
# define WMEMSET_SYMBOL(p,s) p##_avx2_##s
# endif
+# define USE_XMM_LESS_VEC
# include "memset-vec-unaligned-erms.S"
#endif
diff --git a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
index f14d6f8493..5241216a77 100644
--- a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
@@ -15,13 +15,19 @@
# define VZEROUPPER
-# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
- movq r, %rax; \
- vpbroadcastb d, %VEC0
+# define MEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
+ vpbroadcastb d, %VEC0; \
+ movq r, %rax
-# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
- movq r, %rax; \
- vpbroadcastd d, %VEC0
+# define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
+ vpbroadcastd d, %VEC0; \
+ movq r, %rax
+
+# define MEMSET_VDUP_TO_VEC0_HIGH()
+# define MEMSET_VDUP_TO_VEC0_LOW()
+
+# define WMEMSET_VDUP_TO_VEC0_HIGH()
+# define WMEMSET_VDUP_TO_VEC0_LOW()
# define SECTION(p) p##.evex512
# define MEMSET_SYMBOL(p,s) p##_avx512_##s
diff --git a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S
index 64b09e77cc..6370021506 100644
--- a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S
@@ -15,13 +15,19 @@
# define VZEROUPPER
-# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
- movq r, %rax; \
- vpbroadcastb d, %VEC0
+# define MEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
+ vpbroadcastb d, %VEC0; \
+ movq r, %rax
-# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
- movq r, %rax; \
- vpbroadcastd d, %VEC0
+# define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
+ vpbroadcastd d, %VEC0; \
+ movq r, %rax
+
+# define MEMSET_VDUP_TO_VEC0_HIGH()
+# define MEMSET_VDUP_TO_VEC0_LOW()
+
+# define WMEMSET_VDUP_TO_VEC0_HIGH()
+# define WMEMSET_VDUP_TO_VEC0_LOW()
# define SECTION(p) p##.evex
# define MEMSET_SYMBOL(p,s) p##_evex_##s
diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
index 1e0511c79a..fb9053f4d6 100644
--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
@@ -58,8 +58,10 @@
#ifndef MOVQ
# if VEC_SIZE > 16
# define MOVQ vmovq
+# define MOVD vmovd
# else
# define MOVQ movq
+# define MOVD movd
# endif
#endif
@@ -72,9 +74,17 @@
#if defined USE_WITH_EVEX || defined USE_WITH_AVX512
# define END_REG rcx
# define LOOP_REG rdi
+# define LESS_VEC_REG rax
#else
# define END_REG rdi
# define LOOP_REG rdx
+# define LESS_VEC_REG rdi
+#endif
+
+#ifdef USE_XMM_LESS_VEC
+# define XMM_SMALL 1
+#else
+# define XMM_SMALL 0
#endif
#define PAGE_SIZE 4096
@@ -110,8 +120,12 @@ END_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))
shl $2, %RDX_LP
- WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
- jmp L(entry_from_bzero)
+ WMEMSET_SET_VEC0_AND_SET_RETURN (%esi, %rdi)
+ WMEMSET_VDUP_TO_VEC0_LOW()
+ cmpq $VEC_SIZE, %rdx
+ jb L(less_vec_no_vdup)
+ WMEMSET_VDUP_TO_VEC0_HIGH()
+ jmp L(entry_from_wmemset)
END (WMEMSET_SYMBOL (__wmemset, unaligned))
#endif
@@ -123,7 +137,7 @@ END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
#endif
ENTRY (MEMSET_SYMBOL (__memset, unaligned))
- MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
+ MEMSET_SET_VEC0_AND_SET_RETURN (%esi, %rdi)
# ifdef __ILP32__
/* Clear the upper 32 bits. */
mov %edx, %edx
@@ -131,6 +145,8 @@ ENTRY (MEMSET_SYMBOL (__memset, unaligned))
L(entry_from_bzero):
cmpq $VEC_SIZE, %rdx
jb L(less_vec)
+ MEMSET_VDUP_TO_VEC0_HIGH()
+L(entry_from_wmemset):
cmpq $(VEC_SIZE * 2), %rdx
ja L(more_2x_vec)
/* From VEC and to 2 * VEC. No branch when size == VEC_SIZE. */
@@ -179,27 +195,27 @@ END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
# endif
ENTRY_P2ALIGN (MEMSET_SYMBOL (__memset, unaligned_erms), 6)
- MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
+ MEMSET_SET_VEC0_AND_SET_RETURN (%esi, %rdi)
# ifdef __ILP32__
/* Clear the upper 32 bits. */
mov %edx, %edx
# endif
cmp $VEC_SIZE, %RDX_LP
jb L(less_vec)
+ MEMSET_VDUP_TO_VEC0_HIGH ()
cmp $(VEC_SIZE * 2), %RDX_LP
ja L(stosb_more_2x_vec)
- /* From VEC and to 2 * VEC. No branch when size == VEC_SIZE.
- */
- VMOVU %VEC(0), (%rax)
- VMOVU %VEC(0), -VEC_SIZE(%rax, %rdx)
+ /* From VEC and to 2 * VEC. No branch when size == VEC_SIZE. */
+ VMOVU %VEC(0), (%rdi)
+ VMOVU %VEC(0), (VEC_SIZE * -1)(%rdi, %rdx)
VZEROUPPER_RETURN
#endif
- .p2align 4,, 10
+ .p2align 4,, 4
L(last_2x_vec):
#ifdef USE_LESS_VEC_MASK_STORE
- VMOVU %VEC(0), (VEC_SIZE * 2 + LOOP_4X_OFFSET)(%rcx)
- VMOVU %VEC(0), (VEC_SIZE * 3 + LOOP_4X_OFFSET)(%rcx)
+ VMOVU %VEC(0), (VEC_SIZE * -2)(%rdi, %rdx)
+ VMOVU %VEC(0), (VEC_SIZE * -1)(%rdi, %rdx)
#else
VMOVU %VEC(0), (VEC_SIZE * -2)(%rdi)
VMOVU %VEC(0), (VEC_SIZE * -1)(%rdi)
@@ -212,6 +228,7 @@ L(last_2x_vec):
#ifdef USE_LESS_VEC_MASK_STORE
.p2align 4,, 10
L(less_vec):
+L(less_vec_no_vdup):
/* Less than 1 VEC. */
# if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64
# error Unsupported VEC_SIZE!
@@ -262,28 +279,18 @@ L(stosb_more_2x_vec):
/* Fallthrough goes to L(loop_4x_vec). Tests for memset (2x, 4x]
and (4x, 8x] jump to target. */
L(more_2x_vec):
-
- /* Two different methods of setting up pointers / compare. The
- two methods are based on the fact that EVEX/AVX512 mov
- instructions take more bytes then AVX2/SSE2 mov instructions. As
- well that EVEX/AVX512 machines also have fast LEA_BID. Both
- setup and END_REG to avoid complex address mode. For EVEX/AVX512
- this saves code size and keeps a few targets in one fetch block.
- For AVX2/SSE2 this helps prevent AGU bottlenecks. */
-#if defined USE_WITH_EVEX || defined USE_WITH_AVX512
- /* If EVEX/AVX512 compute END_REG - (VEC_SIZE * 4 +
- LOOP_4X_OFFSET) with LEA_BID. */
-
- /* END_REG is rcx for EVEX/AVX512. */
- leaq -(VEC_SIZE * 4 + LOOP_4X_OFFSET)(%rdi, %rdx), %END_REG
-#endif
-
- /* Stores to first 2x VEC before cmp as any path forward will
- require it. */
- VMOVU %VEC(0), (%rax)
- VMOVU %VEC(0), VEC_SIZE(%rax)
+ /* Store next 2x vec regardless. */
+ VMOVU %VEC(0), (%rdi)
+ VMOVU %VEC(0), (VEC_SIZE * 1)(%rdi)
+ /* Two different methods of setting up pointers / compare. The two
+ methods are based on the fact that EVEX/AVX512 mov instructions take
+ more bytes then AVX2/SSE2 mov instructions. As well that EVEX/AVX512
+ machines also have fast LEA_BID. Both setup and END_REG to avoid complex
+ address mode. For EVEX/AVX512 this saves code size and keeps a few
+ targets in one fetch block. For AVX2/SSE2 this helps prevent AGU
+ bottlenecks. */
#if !(defined USE_WITH_EVEX || defined USE_WITH_AVX512)
/* If AVX2/SSE2 compute END_REG (rdi) with ALU. */
addq %rdx, %END_REG
@@ -292,6 +299,15 @@ L(more_2x_vec):
cmpq $(VEC_SIZE * 4), %rdx
jbe L(last_2x_vec)
+
+#if defined USE_WITH_EVEX || defined USE_WITH_AVX512
+ /* If EVEX/AVX512 compute END_REG - (VEC_SIZE * 4 + LOOP_4X_OFFSET) with
+ LEA_BID. */
+
+ /* END_REG is rcx for EVEX/AVX512. */
+ leaq -(VEC_SIZE * 4 + LOOP_4X_OFFSET)(%rdi, %rdx), %END_REG
+#endif
+
/* Store next 2x vec regardless. */
VMOVU %VEC(0), (VEC_SIZE * 2)(%rax)
VMOVU %VEC(0), (VEC_SIZE * 3)(%rax)
@@ -355,65 +371,92 @@ L(stosb_local):
/* Define L(less_vec) only if not otherwise defined. */
.p2align 4
L(less_vec):
+ /* Broadcast esi to partial register (i.e VEC_SIZE == 32 broadcast to
+ xmm). This is only does anything for AVX2. */
+ MEMSET_VDUP_TO_VEC0_LOW ()
+L(less_vec_no_vdup):
#endif
L(cross_page):
#if VEC_SIZE > 32
cmpl $32, %edx
- jae L(between_32_63)
+ jge L(between_32_63)
#endif
#if VEC_SIZE > 16
cmpl $16, %edx
- jae L(between_16_31)
+ jge L(between_16_31)
+#endif
+#ifndef USE_XMM_LESS_VEC
+ MOVQ %XMM0, %rcx
#endif
- MOVQ %XMM0, %rdi
cmpl $8, %edx
- jae L(between_8_15)
+ jge L(between_8_15)
cmpl $4, %edx
- jae L(between_4_7)
+ jge L(between_4_7)
cmpl $1, %edx
- ja L(between_2_3)
- jb L(return)
- movb %sil, (%rax)
- VZEROUPPER_RETURN
+ jg L(between_2_3)
+ jl L(return)
+ movb %sil, (%LESS_VEC_REG)
+ ret
- /* Align small targets only if not doing so would cross a fetch
- line. */
+ /* Align small targets only if not doing so would cross a fetch line.
+ */
#if VEC_SIZE > 32
.p2align 4,, SMALL_MEMSET_ALIGN(MOV_SIZE, RET_SIZE)
/* From 32 to 63. No branch when size == 32. */
L(between_32_63):
- VMOVU %YMM0, (%rax)
- VMOVU %YMM0, -32(%rax, %rdx)
+ VMOVU %YMM0, (%LESS_VEC_REG)
+ VMOVU %YMM0, -32(%LESS_VEC_REG, %rdx)
VZEROUPPER_RETURN
#endif
#if VEC_SIZE >= 32
- .p2align 4,, SMALL_MEMSET_ALIGN(MOV_SIZE, RET_SIZE)
+ .p2align 4,, SMALL_MEMSET_ALIGN(MOV_SIZE, 1)
L(between_16_31):
/* From 16 to 31. No branch when size == 16. */
- VMOVU %XMM0, (%rax)
- VMOVU %XMM0, -16(%rax, %rdx)
- VZEROUPPER_RETURN
+ VMOVU %XMM0, (%LESS_VEC_REG)
+ VMOVU %XMM0, -16(%LESS_VEC_REG, %rdx)
+ ret
#endif
- .p2align 4,, SMALL_MEMSET_ALIGN(3, RET_SIZE)
+ /* Move size is 3 for SSE2, EVEX, and AVX512. Move size is 4 for AVX2.
+ */
+ .p2align 4,, SMALL_MEMSET_ALIGN(3 + XMM_SMALL, 1)
L(between_8_15):
/* From 8 to 15. No branch when size == 8. */
- movq %rdi, (%rax)
- movq %rdi, -8(%rax, %rdx)
- VZEROUPPER_RETURN
+#ifdef USE_XMM_LESS_VEC
+ MOVQ %XMM0, (%rdi)
+ MOVQ %XMM0, -8(%rdi, %rdx)
+#else
+ movq %rcx, (%LESS_VEC_REG)
+ movq %rcx, -8(%LESS_VEC_REG, %rdx)
+#endif
+ ret
- .p2align 4,, SMALL_MEMSET_ALIGN(2, RET_SIZE)
+ /* Move size is 2 for SSE2, EVEX, and AVX512. Move size is 4 for AVX2.
+ */
+ .p2align 4,, SMALL_MEMSET_ALIGN(2 << XMM_SMALL, 1)
L(between_4_7):
/* From 4 to 7. No branch when size == 4. */
- movl %edi, (%rax)
- movl %edi, -4(%rax, %rdx)
- VZEROUPPER_RETURN
+#ifdef USE_XMM_LESS_VEC
+ MOVD %XMM0, (%rdi)
+ MOVD %XMM0, -4(%rdi, %rdx)
+#else
+ movl %ecx, (%LESS_VEC_REG)
+ movl %ecx, -4(%LESS_VEC_REG, %rdx)
+#endif
+ ret
- .p2align 4,, SMALL_MEMSET_ALIGN(3, RET_SIZE)
+ /* 4 * XMM_SMALL for the third mov for AVX2. */
+ .p2align 4,, 4 * XMM_SMALL + SMALL_MEMSET_ALIGN(3, 1)
L(between_2_3):
/* From 2 to 3. No branch when size == 2. */
- movw %di, (%rax)
- movb %dil, -1(%rax, %rdx)
- VZEROUPPER_RETURN
+#ifdef USE_XMM_LESS_VEC
+ movb %sil, (%rdi)
+ movb %sil, 1(%rdi)
+ movb %sil, -1(%rdi, %rdx)
+#else
+ movw %cx, (%LESS_VEC_REG)
+ movb %sil, -1(%LESS_VEC_REG, %rdx)
+#endif
+ ret
END (MEMSET_SYMBOL (__memset, unaligned_erms))
--
2.25.1
next reply other threads:[~2022-02-05 22:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-05 22:42 Noah Goldstein [this message]
2022-02-05 22:50 ` H.J. Lu
2022-02-06 6:54 ` [PATCH v2] " Noah Goldstein
2022-02-06 16:28 ` H.J. Lu
2022-02-07 3:48 ` Noah Goldstein
2022-05-04 5:46 ` Sunil Pandey
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220205224201.1166468-1-goldstein.w.n@gmail.com \
--to=goldstein.w.n@gmail.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).