[PATCH] powerpc: Optimized rawmemchr for POWER9
Anton Blanchard
anton@ozlabs.org
Thu May 14 11:49:16 GMT 2020
This version uses vector instructions and is up to 60% faster on medium
matches and up to 90% faster on long matches, compared to the POWER7
version. A few examples:
__rawmemchr_power9 __rawmemchr_power7
Length 32, alignment 0: 2.27566 3.77765
Length 64, alignment 2: 2.46231 3.51064
Length 1024, alignment 0: 17.3059 32.6678
---
.../powerpc/powerpc64/le/power9/rawmemchr.S | 107 ++++++++++++++++++
sysdeps/powerpc/powerpc64/multiarch/Makefile | 2 +-
.../powerpc64/multiarch/ifunc-impl-list.c | 5 +
.../powerpc64/multiarch/rawmemchr-power9.S | 21 ++++
.../powerpc/powerpc64/multiarch/rawmemchr.c | 12 +-
5 files changed, 144 insertions(+), 3 deletions(-)
create mode 100644 sysdeps/powerpc/powerpc64/le/power9/rawmemchr.S
create mode 100644 sysdeps/powerpc/powerpc64/multiarch/rawmemchr-power9.S
diff --git a/sysdeps/powerpc/powerpc64/le/power9/rawmemchr.S b/sysdeps/powerpc/powerpc64/le/power9/rawmemchr.S
new file mode 100644
index 0000000000..9d0276c931
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/le/power9/rawmemchr.S
@@ -0,0 +1,107 @@
+/* Optimized rawmemchr implementation for PowerPC64/POWER9.
+ Copyright (C) 2020 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/>. */
+
+#include <sysdep.h>
+
+#ifndef RAWMEMCHR
+# define RAWMEMCHR __rawmemchr
+#endif
+
+/* Implements the function
+
+ int [r3] rawmemchr (void *s [r3], int c [r4])
+
+ The implementation can load bytes past a matching byte, but only
+ up to the next 16B boundary, so it never crosses a page. */
+
+.machine power9
+ENTRY_TOCLESS (RAWMEMCHR, 4)
+ CALL_MCOUNT 2
+
+ xori r5,r4,0xff
+
+ mtvsrd v18+32,r4 /* matching char in v18 */
+ mtvsrd v19+32,r5 /* non matching char in v19 */
+
+ vspltb v18,v18,7 /* replicate */
+ vspltb v19,v19,7 /* replicate */
+
+ neg r5,r3
+ rldicl r9,r5,0,60 /* How many bytes to get source 16B aligned? */
+
+ /* Align data and fill bytes not loaded with non matching char */
+ lvx v0,0,r3
+ lvsr v1,0,r3
+ vperm v0,v19,v0,v1
+
+ vcmpequb. v6,v0,v18 /* 0xff if byte matches, 0x00 otherwise */
+ beq cr6,L(aligned)
+
+ vctzlsbb r0,v6
+ add r3,r3,r0
+ blr
+
+L(aligned):
+ add r3,r3,r9
+
+L(loop):
+ lxv v0+32,0(r3)
+ vcmpequb. v6,v0,v18 /* 0xff if byte matches, 0x00 otherwise */
+ bne cr6,L(tail1)
+
+ lxv v0+32,16(r3)
+ vcmpequb. v6,v0,v18 /* 0xff if byte matches, 0x00 otherwise */
+ bne cr6,L(tail2)
+
+ lxv v0+32,32(r3)
+ vcmpequb. v6,v0,v18 /* 0xff if byte matches, 0x00 otherwise */
+ bne cr6,L(tail3)
+
+ lxv v0+32,48(r3)
+ vcmpequb. v6,v0,v18 /* 0xff if byte matches, 0x00 otherwise */
+ bne cr6,L(tail4)
+
+ addi r3,r3,64
+ b L(loop)
+
+L(tail1):
+ vctzlsbb r0,v6
+ add r3,r3,r0
+ blr
+
+L(tail2):
+ vctzlsbb r0,v6
+ add r3,r3,r0
+ addi r3,r3,16
+ blr
+
+L(tail3):
+ vctzlsbb r0,v6
+ add r3,r3,r0
+ addi r3,r3,32
+ blr
+
+L(tail4):
+ vctzlsbb r0,v6
+ add r3,r3,r0
+ addi r3,r3,48
+ blr
+
+END (RAWMEMCHR)
+weak_alias (__rawmemchr,rawmemchr)
+libc_hidden_builtin_def (__rawmemchr)
diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index ea936bf9ed..3b04512f1d 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -32,7 +32,7 @@ sysdep_routines += memcpy-power8-cached memcpy-power7 memcpy-a2 memcpy-power6 \
strncase-power8
ifneq (,$(filter %le,$(config-machine)))
-sysdep_routines += strcmp-power9 strncmp-power9
+sysdep_routines += strcmp-power9 strncmp-power9 rawmemchr-power9
endif
CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index b9fef3f43c..386bb6936c 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -208,6 +208,11 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
/* Support sysdeps/powerpc/powerpc64/multiarch/rawmemchr.c. */
IFUNC_IMPL (i, name, rawmemchr,
+#ifdef __LITTLE_ENDIAN__
+ IFUNC_IMPL_ADD (array, i, rawmemchr,
+ hwcap2 & PPC_FEATURE2_ARCH_3_00,
+ __rawmemchr_power9)
+#endif
IFUNC_IMPL_ADD (array, i, rawmemchr,
hwcap & PPC_FEATURE_HAS_VSX,
__rawmemchr_power7)
diff --git a/sysdeps/powerpc/powerpc64/multiarch/rawmemchr-power9.S b/sysdeps/powerpc/powerpc64/multiarch/rawmemchr-power9.S
new file mode 100644
index 0000000000..bac0a9090e
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/rawmemchr-power9.S
@@ -0,0 +1,21 @@
+/* Optimized rawmemchr implementation for PowerPC64/POWER9.
+ Copyright (C) 2020 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/>. */
+
+#define RAWMEMCHR __rawmemchr_power9
+
+#include <sysdeps/powerpc/powerpc64/le/power9/rawmemchr.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/rawmemchr.c b/sysdeps/powerpc/powerpc64/multiarch/rawmemchr.c
index 847157e5f0..c49c0c51ff 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/rawmemchr.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/rawmemchr.c
@@ -24,13 +24,21 @@
extern __typeof (__rawmemchr) __rawmemchr_ppc attribute_hidden;
extern __typeof (__rawmemchr) __rawmemchr_power7 attribute_hidden;
+# ifdef __LITTLE_ENDIAN__
+extern __typeof (__rawmemchr) __rawmemchr_power9 attribute_hidden;
+# endif
+
# undef __rawmemchr
/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
ifunc symbol properly. */
libc_ifunc_redirected (__redirect___rawmemchr, __rawmemchr,
- (hwcap & PPC_FEATURE_HAS_VSX)
- ? __rawmemchr_power7
+# ifdef __LITTLE_ENDIAN__
+ (hwcap2 & PPC_FEATURE2_ARCH_3_00)
+ ? __rawmemchr_power9 :
+# endif
+ (hwcap & PPC_FEATURE_HAS_VSX)
+ ? __rawmemchr_power7
: __rawmemchr_ppc);
weak_alias (__rawmemchr, rawmemchr)
--
2.26.2
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