[PATCH v2 1/2] powerpc: Add optimized strncpy for POWER9
Raphael Moreira Zinsly
rzinsly@linux.ibm.com
Fri Sep 4 16:56:52 GMT 2020
Changes since v1:
- Fixed comments identation and added some spaces to improve
readbillity.
- Use "POWER 9 LE" instead of "PowerPC64/POWER9".
- Fixed copyright dates.
- Replaced cmpwi for cmpdi.
---8<---
Similar to the strcpy P9 optimization, this version uses VSX to improve
performance.
---
sysdeps/powerpc/powerpc64/le/power9/strncpy.S | 281 ++++++++++++++++++
sysdeps/powerpc/powerpc64/multiarch/Makefile | 2 +-
.../powerpc64/multiarch/ifunc-impl-list.c | 5 +
.../powerpc64/multiarch/strncpy-power9.S | 26 ++
sysdeps/powerpc/powerpc64/multiarch/strncpy.c | 7 +
5 files changed, 320 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/powerpc/powerpc64/le/power9/strncpy.S
create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strncpy-power9.S
diff --git a/sysdeps/powerpc/powerpc64/le/power9/strncpy.S b/sysdeps/powerpc/powerpc64/le/power9/strncpy.S
new file mode 100644
index 0000000000..34fcdee913
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/le/power9/strncpy.S
@@ -0,0 +1,281 @@
+/* Optimized strncpy implementation for POWER9 LE.
+ 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 STRNCPY
+# define FUNC_NAME strncpy
+# else
+# define FUNC_NAME STRNCPY
+# endif
+
+/* Implements the function
+
+ char * [r3] strncpy (char *dest [r3], const char *src [r4], size_t n [r5])
+
+ The implementation can load bytes past a null terminator, but only
+ up to the next 16-byte aligned address, so it never crosses a page. */
+
+.machine power9
+ENTRY_TOCLESS (FUNC_NAME, 4)
+ CALL_MCOUNT 2
+
+ /* NULL string optimizations */
+ cmpdi r5, 0
+ beqlr
+
+ lbz r0,0(r4)
+ stb r0,0(r3)
+ addi r11,r3,1
+ addi r5,r5,-1
+ vspltisb v18,0 /* Zeroes in v18 */
+ cmpdi r0,0
+ beq L(zero_padding_loop)
+
+ /* Empty/1-byte string optimization */
+ cmpdi r5,0
+ beqlr
+
+ addi r4,r4,1
+ neg r7,r4
+ rldicl r9,r7,0,60 /* How many bytes to get source 16B aligned? */
+
+ /* Get source 16B aligned */
+ lvx v0,0,r4
+ lvsr v1,0,r4
+ vperm v0,v18,v0,v1
+
+ vcmpequb v6,v0,v18 /* 0xff if byte is NULL, 0x00 otherwise */
+ vctzlsbb r7,v6 /* Number of trailing zeroes */
+ addi r8,r7,1 /* Add null terminator */
+
+ /* r8 = bytes including null
+ r9 = bytes to get source 16B aligned
+ if r8 > r9
+ no null, copy r9 bytes
+ else
+ there is a null, copy r8 bytes and return. */
+ cmpld r8,r9
+ bgt L(no_null)
+
+ cmpld cr6,r8,r5 /* r8 <= n? */
+ ble cr6,L(null)
+
+ sldi r10,r5,56 /* stxvl wants size in top 8 bits */
+ stxvl 32+v0,r11,r10 /* Partial store */
+
+ blr
+
+L(null):
+ sldi r10,r8,56 /* stxvl wants size in top 8 bits */
+ stxvl 32+v0,r11,r10 /* Partial store */
+
+ add r11,r11,r8
+ sub r5,r5,r8
+ b L(zero_padding_loop)
+
+L(no_null):
+ cmpld r9,r5 /* Check if length was reached. */
+ bge L(n_tail1)
+
+ sldi r10,r9,56 /* stxvl wants size in top 8 bits */
+ stxvl 32+v0,r11,r10 /* Partial store */
+
+ add r4,r4,r9
+ add r11,r11,r9
+ sub r5,r5,r9
+
+L(loop):
+ cmpldi cr6,r5,64 /* Check if length was reached. */
+ ble cr6,L(final_loop)
+
+ lxv 32+v0,0(r4)
+ vcmpequb. v6,v0,v18 /* Any zero bytes? */
+ bne cr6,L(prep_tail1)
+
+ lxv 32+v1,16(r4)
+ vcmpequb. v6,v1,v18 /* Any zero bytes? */
+ bne cr6,L(prep_tail2)
+
+ lxv 32+v2,32(r4)
+ vcmpequb. v6,v2,v18 /* Any zero bytes? */
+ bne cr6,L(prep_tail3)
+
+ lxv 32+v3,48(r4)
+ vcmpequb. v6,v3,v18 /* Any zero bytes? */
+ bne cr6,L(prep_tail4)
+
+ stxv 32+v0,0(r11)
+ stxv 32+v1,16(r11)
+ stxv 32+v2,32(r11)
+ stxv 32+v3,48(r11)
+
+ addi r4,r4,64
+ addi r11,r11,64
+ addi r5,r5,-64
+
+ b L(loop)
+
+L(final_loop):
+ cmpldi cr5,r5,16
+ lxv 32+v0,0(r4)
+ vcmpequb. v6,v0,v18 /* Any zero bytes? */
+ ble cr5,L(prep_n_tail1)
+ bne cr6,L(count_tail1)
+ addi r5,r5,-16
+
+ cmpldi cr5,r5,16
+ lxv 32+v1,16(r4)
+ vcmpequb. v6,v1,v18 /* Any zero bytes? */
+ ble cr5,L(prep_n_tail2)
+ bne cr6,L(count_tail2)
+ addi r5,r5,-16
+
+ cmpldi cr5,r5,16
+ lxv 32+v2,32(r4)
+ vcmpequb. v6,v2,v18 /* Any zero bytes? */
+ ble cr5,L(prep_n_tail3)
+ bne cr6,L(count_tail3)
+ addi r5,r5,-16
+
+ lxv 32+v3,48(r4)
+ vcmpequb. v6,v3,v18 /* Any zero bytes? */
+ beq cr6,L(n_tail4)
+
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+ cmpld r8,r5 /* r8 < n? */
+ blt L(tail4)
+
+L(n_tail4):
+ stxv 32+v0,0(r11)
+ stxv 32+v1,16(r11)
+ stxv 32+v2,32(r11)
+ sldi r10,r5,56 /* stxvl wants size in top 8 bits */
+ addi r11,r11,48 /* Offset */
+ stxvl 32+v3,r11,r10 /* Partial store */
+ blr
+
+L(prep_n_tail1):
+ beq cr6,L(n_tail1) /* Any zero bytes? */
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+ cmpld r8,r5 /* r8 < n? */
+ blt L(tail1)
+
+L(n_tail1):
+ sldi r10,r5,56 /* stxvl wants size in top 8 bits */
+ stxvl 32+v0,r11,r10 /* Partial store */
+ blr
+
+L(prep_n_tail2):
+ beq cr6,L(n_tail2) /* Any zero bytes? */
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+ cmpld r8,r5 /* r8 < n? */
+ blt L(tail2)
+
+L(n_tail2):
+ stxv 32+v0,0(r11)
+ sldi r10,r5,56 /* stxvl wants size in top 8 bits */
+ addi r11,r11,16 /* offset */
+ stxvl 32+v1,r11,r10 /* Partial store */
+ blr
+
+L(prep_n_tail3):
+ beq cr6,L(n_tail3) /* Any zero bytes? */
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+ cmpld r8,r5 /* r8 < n? */
+ blt L(tail3)
+
+L(n_tail3):
+ stxv 32+v0,0(r11)
+ stxv 32+v1,16(r11)
+ sldi r10,r5,56 /* stxvl wants size in top 8 bits */
+ addi r11,r11,32 /* Offset */
+ stxvl 32+v2,r11,r10 /* Partial store */
+ blr
+
+L(prep_tail1):
+L(count_tail1):
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+L(tail1):
+ addi r9,r8,1 /* Add null terminator */
+ sldi r10,r9,56 /* stxvl wants size in top 8 bits */
+ stxvl 32+v0,r11,r10 /* Partial store */
+ add r11,r11,r9
+ sub r5,r5,r9
+ b L(zero_padding_loop)
+
+L(prep_tail2):
+ addi r5,r5,-16
+L(count_tail2):
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+L(tail2):
+ addi r9,r8,1 /* Add null terminator */
+ stxv 32+v0,0(r11)
+ sldi r10,r9,56 /* stxvl wants size in top 8 bits */
+ addi r11,r11,16 /* offset */
+ stxvl 32+v1,r11,r10 /* Partial store */
+ add r11,r11,r9
+ sub r5,r5,r9
+ b L(zero_padding_loop)
+
+L(prep_tail3):
+ addi r5,r5,-32
+L(count_tail3):
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+L(tail3):
+ addi r9,r8,1 /* Add null terminator */
+ stxv 32+v0,0(r11)
+ stxv 32+v1,16(r11)
+ sldi r10,r9,56 /* stxvl wants size in top 8 bits */
+ addi r11,r11,32 /* offset */
+ stxvl 32+v2,r11,r10 /* Partial store */
+ add r11,r11,r9
+ sub r5,r5,r9
+ b L(zero_padding_loop)
+
+L(prep_tail4):
+ addi r5,r5,-48
+ vctzlsbb r8,v6 /* Number of trailing zeroes */
+L(tail4):
+ addi r9,r8,1 /* Add null terminator */
+ stxv 32+v0,0(r11)
+ stxv 32+v1,16(r11)
+ stxv 32+v2,32(r11)
+ sldi r10,r9,56 /* stxvl wants size in top 8 bits */
+ addi r11,r11,48 /* offset */
+ stxvl 32+v3,r11,r10 /* Partial store */
+ add r11,r11,r9
+ sub r5,r5,r9
+
+/* This code pads the remainder of dest with NULL bytes. */
+L(zero_padding_loop):
+ cmpldi cr6,r5,16 /* Check if length was reached. */
+ ble cr6,L(zero_padding_end)
+
+ stxv v18,0(r11)
+ addi r11,r11,16
+ addi r5,r5,-16
+
+ b L(zero_padding_loop)
+
+L(zero_padding_end):
+ sldi r10,r5,56 /* stxvl wants size in top 8 bits */
+ stxvl v18,r11,r10 /* Partial store */
+ blr
+
+END (FUNC_NAME)
diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index 19acb6c64a..cd2b47b403 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -33,7 +33,7 @@ sysdep_routines += memcpy-power8-cached memcpy-power7 memcpy-a2 memcpy-power6 \
ifneq (,$(filter %le,$(config-machine)))
sysdep_routines += strcmp-power9 strncmp-power9 strcpy-power9 stpcpy-power9 \
- rawmemchr-power9 strlen-power9
+ rawmemchr-power9 strlen-power9 strncpy-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 ea10b00417..aa63e1c23f 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -301,6 +301,11 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
/* Support sysdeps/powerpc/powerpc64/multiarch/strncpy.c. */
IFUNC_IMPL (i, name, strncpy,
+#ifdef __LITTLE_ENDIAN__
+ IFUNC_IMPL_ADD (array, i, strncpy,
+ hwcap2 & PPC_FEATURE2_ARCH_3_00,
+ __strncpy_power9)
+#endif
IFUNC_IMPL_ADD (array, i, strncpy,
hwcap2 & PPC_FEATURE2_ARCH_2_07,
__strncpy_power8)
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncpy-power9.S b/sysdeps/powerpc/powerpc64/multiarch/strncpy-power9.S
new file mode 100644
index 0000000000..ab7c570d54
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncpy-power9.S
@@ -0,0 +1,26 @@
+/* Optimized strncpy implementation for POWER9 LE.
+ 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/>. */
+
+#if defined __LITTLE_ENDIAN__ && IS_IN (libc)
+#define STRNCPY __strncpy_power9
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/le/power9/strncpy.S>
+#endif
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncpy.c b/sysdeps/powerpc/powerpc64/multiarch/strncpy.c
index 7bacf28aca..8ef0a99cb5 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strncpy.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncpy.c
@@ -28,11 +28,18 @@
extern __typeof (strncpy) __strncpy_ppc attribute_hidden;
extern __typeof (strncpy) __strncpy_power7 attribute_hidden;
extern __typeof (strncpy) __strncpy_power8 attribute_hidden;
+# ifdef __LITTLE_ENDIAN__
+extern __typeof (strncpy) __strncpy_power9 attribute_hidden;
+# endif
# undef strncpy
/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
ifunc symbol properly. */
libc_ifunc_redirected (__redirect_strncpy, strncpy,
+# ifdef __LITTLE_ENDIAN__
+ (hwcap2 & PPC_FEATURE2_ARCH_3_00)
+ ? __strncpy_power9 :
+# endif
(hwcap2 & PPC_FEATURE2_ARCH_2_07)
? __strncpy_power8
: (hwcap & PPC_FEATURE_HAS_VSX)
--
2.26.2
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