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[PATCH] powerpc: strcmp optimization for power9
- From: Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Cc: sjmunroe at us dot ibm dot com, Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- Date: Mon, 14 Nov 2016 16:59:03 +0530
- Subject: [PATCH] powerpc: strcmp optimization for power9
- Authentication-results: sourceware.org; auth=none
Vectorized loops are used for strings > 32B when compared
to power8 optimization.
Tested on power9 ppc64le simulator.
2016-11-14 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
* sysdeps/powerpc/powerpc64/multiarch/Makefile
(sysdep_routines): Add strcmp_power9.
* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
(strcmp): Add __strcmp_power9 to list of strcmp functions.
* sysdeps/powerpc/powerpc64/multiarch/strcmp-power9.S: New file.
* sysdeps/powerpc/powerpc64/multiarch/strcmp.c
(strcmp): Add __strcmp_power9 to ifunc list.
* sysdeps/powerpc/powerpc64/power9/strcmp.S: New file.
---
sysdeps/powerpc/powerpc64/multiarch/Makefile | 2 +-
.../powerpc/powerpc64/multiarch/ifunc-impl-list.c | 3 +
.../powerpc/powerpc64/multiarch/strcmp-power9.S | 40 +++
sysdeps/powerpc/powerpc64/multiarch/strcmp.c | 4 +
sysdeps/powerpc/powerpc64/power9/strcmp.S | 279 +++++++++++++++++++++
5 files changed, 327 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-power9.S
create mode 100644 sysdeps/powerpc/powerpc64/power9/strcmp.S
diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index e3ac285..2c83c22 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -16,7 +16,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
strncpy-power7 strncpy-ppc64 \
stpncpy-power8 stpncpy-power7 stpncpy-ppc64 \
- strcmp-power8 strcmp-power7 strcmp-ppc64 \
+ strcmp-power9 strcmp-power8 strcmp-power7 strcmp-ppc64 \
strcat-power8 strcat-power7 strcat-ppc64 \
memmove-power7 memmove-ppc64 wordcopy-ppc64 bcopy-ppc64 \
strncpy-power8 strstr-power7 strstr-ppc64 \
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index 9f6bd7c..4427941 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -311,6 +311,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
/* Support sysdeps/powerpc/powerpc64/multiarch/strcmp.c. */
IFUNC_IMPL (i, name, strcmp,
IFUNC_IMPL_ADD (array, i, strcmp,
+ hwcap2 & PPC_FEATURE2_ARCH_3_00,
+ __strcmp_power9)
+ IFUNC_IMPL_ADD (array, i, strcmp,
hwcap2 & PPC_FEATURE2_ARCH_2_07,
__strcmp_power8)
IFUNC_IMPL_ADD (array, i, strcmp,
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-power9.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power9.S
new file mode 100644
index 0000000..0a09e5b
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power9.S
@@ -0,0 +1,40 @@
+/* Optimized strcmp implementation for POWER9/PPC64.
+ Copyright (C) 2016 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+#undef EALIGN
+#define EALIGN(name, alignt, words) \
+ .section ".text"; \
+ ENTRY_2(__strcmp_power9) \
+ .align ALIGNARG(alignt); \
+ EALIGN_W_##words; \
+ BODY_LABEL(__strcmp_power9): \
+ cfi_startproc; \
+ LOCALENTRY(__strcmp_power9)
+
+#undef END
+#define END(name) \
+ cfi_endproc; \
+ TRACEBACK(__strcmp_power9) \
+ END_2(__strcmp_power9)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/power9/strcmp.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp.c b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
index 06f89cb..6e8d699 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
@@ -27,9 +27,13 @@
extern __typeof (strcmp) __strcmp_ppc attribute_hidden;
extern __typeof (strcmp) __strcmp_power7 attribute_hidden;
extern __typeof (strcmp) __strcmp_power8 attribute_hidden;
+extern __typeof (strcmp) __strcmp_power9 attribute_hidden;
+
# undef strcmp
libc_ifunc_redirected (__redirect_strcmp, strcmp,
+ (hwcap2 & PPC_FEATURE2_ARCH_3_00)
+ ? __strcmp_power9 :
(hwcap2 & PPC_FEATURE2_ARCH_2_07)
? __strcmp_power8
: (hwcap & PPC_FEATURE_HAS_VSX)
diff --git a/sysdeps/powerpc/powerpc64/power9/strcmp.S b/sysdeps/powerpc/powerpc64/power9/strcmp.S
new file mode 100644
index 0000000..cc24296
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power9/strcmp.S
@@ -0,0 +1,279 @@
+/* Optimized strcmp implementation for PowerPC64/POWER9.
+ Copyright (C) 2016 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
+ <http://www.gnu.org/licenses/>. */
+#ifdef __LITTLE_ENDIAN__
+#include <sysdep.h>
+
+/* Implements the function
+
+ int [r3] strcmp (const char *s1 [r3], const char *s2 [r4])
+
+ The implementation uses unaligned doubleword access for first 32 bytes
+ as in POWER8 path and uses vectorised loops after that. */
+
+/* Macros are defined below for these newer instructions in order
+ to maintain compatibility. */
+# define VCTZLSBB(r,v) .long (0x10010602 | ((r)<<(32-11)) | ((v)<<(32-21)))
+
+# define VEXTUBRX(t,a,b) .long (0x1000070d \
+ | ((t)<<(32-11)) \
+ | ((a)<<(32-16)) \
+ | ((b)<<(32-21)) )
+
+# define VCMPNEZB(t,a,b) .long (0x10000507 \
+ | ((t)<<(32-11)) \
+ | ((a)<<(32-16)) \
+ | ((b)<<(32-21)) )
+
+/* Get 16 bytes for unaligned case.
+ reg1: Vector to hold next 16 bytes.
+ reg2: Address to read from.
+ reg3: Permute control vector. */
+# define GET16BYTES(reg1, reg2, reg3) \
+ lvx reg1, 0, reg2; \
+ vperm v8, v2, reg1, reg3; \
+ vcmpequb. v8, v0, v8; \
+ beq cr6, 1f; \
+ vspltisb v9, 0; \
+ b 2f; \
+ .align 4; \
+1: \
+ addi r6, reg2, 16; \
+ lvx v9, 0, r6; \
+2: \
+ vperm reg1, v9, reg1, reg3;
+
+/* TODO: change this to .machine power9 when the minimum required binutils
+ allows it. */
+
+ .machine power7
+EALIGN (strcmp, 4, 0)
+ li r0, 0
+
+ /* Check if [s1]+32 or [s2]+32 will cross a 4K page boundary using
+ the code:
+
+ (((size_t) s1) % PAGE_SIZE > (PAGE_SIZE - ITER_SIZE))
+
+ with PAGE_SIZE being 4096 and ITER_SIZE begin 32. */
+
+ rldicl r7, r3, 0, 52
+ rldicl r9, r4, 0, 52
+ cmpldi cr7, r7, 4096-32
+ bgt cr7, L(pagecross_check)
+ cmpldi cr5, r9, 4096-32
+ bgt cr5, L(pagecross_check)
+
+ /* For short string up to 32 bytes, load both s1 and s2 using
+ unaligned dwords and compare. */
+ ld r8, 0(r3)
+ ld r10, 0(r4)
+ cmpb r12, r8, r0
+ cmpb r11, r8, r10
+ orc. r9, r12, r11
+ bne cr0, L(different_nocmpb)
+
+ ld r8, 8(r3)
+ ld r10, 8(r4)
+ cmpb r12, r8, r0
+ cmpb r11, r8, r10
+ orc. r9, r12, r11
+ bne cr0, L(different_nocmpb)
+
+ ld r8, 16(r3)
+ ld r10, 16(r4)
+ cmpb r12, r8, r0
+ cmpb r11, r8, r10
+ orc. r9, r12, r11
+ bne cr0, L(different_nocmpb)
+
+ ld r8, 24(r3)
+ ld r10, 24(r4)
+ cmpb r12, r8, r0
+ cmpb r11, r8, r10
+ orc. r9, r12, r11
+ bne cr0, L(different_nocmpb)
+
+ addi r7, r3, 32
+ addi r4, r4, 32
+
+L(align):
+ /* Now it has checked for first 32 bytes. */
+ vspltisb v0, 0
+ vspltisb v2, -1
+ lvsr v6, 0, r4 /* Compute mask. */
+ or r5, r4, r7
+ andi. r5, r5, 0xF
+ beq cr0, L(aligned)
+ andi. r5, r7, 0xF
+ beq cr0, L(s1_align)
+ lvsr v10, 0, r7 /* Compute mask. */
+
+ /* Both s1 and s2 are unaligned. */
+ GET16BYTES(v4, r7, v10)
+ GET16BYTES(v5, r4, v6)
+ VCMPNEZB(v7, v5, v4)
+ beq cr6, L(match)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ b L(different)
+
+ /* Align s1 to qw and adjust s2 address. */
+ .align 4
+L(match):
+ clrldi r6, r7, 60
+ subfic r5, r6, 16
+ add r7, r7, r5
+ add r4, r4, r5
+ andi. r5, r4, 0xF
+ beq cr0, L(aligned)
+ lvsr v6, 0, r4
+ /* There are 2 loops depending on the input alignment.
+ Each loop gets 16 bytes from s1 and s2 and compare.
+ Loop till difference or null occurs. */
+L(s1_align):
+ lvx v4, r7, r0
+ GET16BYTES(v5, r4, v6)
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ bne cr6, L(different)
+
+ lvx v4, r7, r0
+ GET16BYTES(v5, r4, v6)
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ bne cr6, L(different)
+
+ lvx v4, r7, r0
+ GET16BYTES(v5, r4, v6)
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ bne cr6, L(different)
+
+ lvx v4, r7, r0
+ GET16BYTES(v5, r4, v6)
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ beq cr6, L(s1_align)
+ b L(different)
+
+ .align 4
+L(aligned):
+ lvx v4, 0, r7
+ lvx v5, 0, r4
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ bne cr6, L(different)
+
+ lvx v4, 0, r7
+ lvx v5, 0, r4
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ bne cr6, L(different)
+
+ lvx v4, 0, r7
+ lvx v5, 0, r4
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ bne cr6, L(different)
+
+ lvx v4, 0, r7
+ lvx v5, 0, r4
+ VCMPNEZB(v7, v5, v4)
+ addi r7, r7, 16
+ addi r4, r4, 16
+ beq cr6, L(aligned)
+
+ /* Calculate and return the difference. */
+L(different):
+ VCTZLSBB(r6, v7)
+ VEXTUBRX(r5, r6, v4)
+ VEXTUBRX(r4, r6, v5)
+ subf r3, r4, r5
+ extsw r3, r3
+ blr
+
+ .align 4
+L(different_nocmpb):
+ neg r3, r9
+ and r9, r9, r3
+ cntlzd r9, r9
+ subfic r9, r9, 63
+ srd r3, r8, r9
+ srd r10, r10, r9
+ rldicl r10, r10, 0, 56
+ rldicl r3, r3, 0, 56
+ subf r3, r10, r3
+ extsw r3, r3
+ blr
+
+ .align 4
+L(pagecross_check):
+ subfic r9, r9, 4096
+ subfic r7, r7, 4096
+ cmpld cr7, r7, r9
+ bge cr7, L(pagecross)
+ mr r7, r9
+
+ /* If unaligned 16 bytes reads across a 4K page boundary, it uses
+ a simple byte a byte comparison until the page alignment for s1
+ is reached. */
+L(pagecross):
+ add r7, r3, r7
+ subf r9, r3, r7
+ mtctr r9
+
+ .align 4
+L(pagecross_loop):
+ /* Loads a byte from s1 and s2, compare if *s1 is equal to *s2
+ and if *s1 is '\0'. */
+ lbz r9, 0(r3)
+ lbz r10, 0(r4)
+ addi r3, r3, 1
+ addi r4, r4, 1
+ cmplw cr7, r9, r10
+ cmpdi cr5, r9, r0
+ bne cr7, L(pagecross_ne)
+ beq cr5, L(pagecross_nullfound)
+ bdnz L(pagecross_loop)
+ b L(align)
+
+ .align 4
+L(pagecross_ne):
+ extsw r3, r9
+ mr r9, r10
+L(pagecross_retdiff):
+ subf r9, r9, r3
+ extsw r3, r9
+ blr
+
+ .align 4
+L(pagecross_nullfound):
+ li r3, 0
+ b L(pagecross_retdiff)
+END (strcmp)
+libc_hidden_builtin_def (strcmp)
+#else
+#include <sysdeps/powerpc/powerpc64/power8/strcmp.S>
+#endif
--
2.7.4