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[PATCH] powerpc64: strrchr optimization for power8
- From: Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Cc: Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- Date: Thu, 9 Feb 2017 10:30:54 +0530
- Subject: [PATCH] powerpc64: strrchr optimization for power8
- Authentication-results: sourceware.org; auth=none
P7 code is used for <=32B strings and for > 32B vectorized loops are used.
This shows as an average 25% improvement depending on the position of search
character. The performance is same for shorter strings.
Tested on ppc64 and ppc64le.
2017-02-06 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
* sysdeps/powerpc/powerpc64/multiarch/Makefile
(sysdep_routines): Add strrchr-power8.
* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
(strrchr): Add __strrchr_power8 to list of strrchr functions.
* sysdeps/powerpc/powerpc64/multiarch/strrchr-power8.S: New file.
* sysdeps/powerpc/powerpc64/multiarch/strrchr.c
(strrchr): Add __strrchr_power8 to ifunc list.
* sysdeps/powerpc/powerpc64/power8/strrchr.S: New file.
---
sysdeps/powerpc/powerpc64/multiarch/Makefile | 3 +-
.../powerpc/powerpc64/multiarch/ifunc-impl-list.c | 3 +
.../powerpc/powerpc64/multiarch/strrchr-power8.S | 39 ++
sysdeps/powerpc/powerpc64/multiarch/strrchr.c | 3 +
sysdeps/powerpc/powerpc64/power8/strrchr.S | 464 +++++++++++++++++++++
5 files changed, 511 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strrchr-power8.S
create mode 100644 sysdeps/powerpc/powerpc64/power8/strrchr.S
diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index f5889a3..0fc0ebc 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -14,7 +14,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
strchrnul-power8 strchrnul-power7 strchrnul-ppc64 \
strcpy-power8 strcpy-power7 strcpy-ppc64 stpcpy-power8 \
stpcpy-power7 stpcpy-ppc64 \
- strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
+ strrchr-power8 strrchr-power7 strrchr-ppc64 \
+ strncat-power7 strncat-ppc64 \
strncpy-power7 strncpy-ppc64 \
stpncpy-power8 stpncpy-power7 stpncpy-ppc64 \
strcmp-power9 strcmp-power8 strcmp-power7 strcmp-ppc64 \
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index 209aec5..d77c47f 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -281,6 +281,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
/* Support sysdeps/powerpc/powerpc64/multiarch/strrchr.c. */
IFUNC_IMPL (i, name, strrchr,
IFUNC_IMPL_ADD (array, i, strrchr,
+ hwcap2 & PPC_FEATURE2_ARCH_2_07,
+ __strrchr_power8)
+ IFUNC_IMPL_ADD (array, i, strrchr,
hwcap & PPC_FEATURE_HAS_VSX,
__strrchr_power7)
IFUNC_IMPL_ADD (array, i, strrchr, 1,
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strrchr-power8.S b/sysdeps/powerpc/powerpc64/multiarch/strrchr-power8.S
new file mode 100644
index 0000000..23365a1
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strrchr-power8.S
@@ -0,0 +1,39 @@
+/* Optimized strrchr implementation for POWER8.
+ Copyright (C) 2017 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 ENTRY
+#define ENTRY(name) \
+ .section ".text"; \
+ ENTRY_2(__strrchr_power8) \
+ .align ALIGNARG(2); \
+ BODY_LABEL(__strrchr_power8): \
+ cfi_startproc; \
+ LOCALENTRY(__strrchr_power8)
+
+#undef END
+#define END(name) \
+ cfi_endproc; \
+ TRACEBACK(__strrchr_power8) \
+ END_2(__strrchr_power8)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/power8/strrchr.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strrchr.c b/sysdeps/powerpc/powerpc64/multiarch/strrchr.c
index dc1d3d0..0f94c9d 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strrchr.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strrchr.c
@@ -25,11 +25,14 @@
extern __typeof (strrchr) __strrchr_ppc attribute_hidden;
extern __typeof (strrchr) __strrchr_power7 attribute_hidden;
+extern __typeof (strrchr) __strrchr_power8 attribute_hidden;
#undef strrchr
/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
ifunc symbol properly. */
libc_ifunc_redirected (__redirect_strrchr, strrchr,
+ (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+ ? __strrchr_power8 :
(hwcap & PPC_FEATURE_HAS_VSX)
? __strrchr_power7
: __strrchr_ppc);
diff --git a/sysdeps/powerpc/powerpc64/power8/strrchr.S b/sysdeps/powerpc/powerpc64/power8/strrchr.S
new file mode 100644
index 0000000..f29fc4e
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power8/strrchr.S
@@ -0,0 +1,464 @@
+/* Optimized strrchr implementation for PowerPC64/POWER7 using cmpb insn.
+ Copyright (C) 2017 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>
+
+/* int [r3] strrchr (char *s [r3], int c [r4]) */
+/* TODO: change these to the actual instructions when the minimum required
+ binutils allows it. */
+#define MTVRD(v,r) .long (0x7c000167 | ((v)<<(32-11)) | ((r)<<(32-16)))
+#define MFVRD(r,v) .long (0x7c000067 | ((v)<<(32-11)) | ((r)<<(32-16)))
+#define VBPERMQ(t,a,b) .long (0x1000054c \
+ | ((t)<<(32-11)) \
+ | ((a)<<(32-16)) \
+ | ((b)<<(32-21)) )
+#define VCLZD(r,v) .long (0x100007c2 | ((r)<<(32-11)) | ((v)<<(32-21)))
+#define VPOPCNTD(r,v) .long (0x100007c3 | ((r)<<(32-11)) | ((v)<<(32-21)))
+#define VADDUQM(t,a,b) .long (0x10000100 \
+ | ((t)<<(32-11)) \
+ | ((a)<<(32-16)) \
+ | ((b)<<(32-21)) )
+#ifdef __LITTLE_ENDIAN__
+/* Find the match position from v6 and place result in r6. */
+# define CALCULATE_MATCH() \
+ VBPERMQ(v6, v6, v10); \
+ vsldoi v6, v6, v6, 6; \
+ MFVRD(r7, v6); \
+ cntlzd r6, r7; \
+ subfic r6, r6, 15;
+/*
+ * Find the first null position to mask bytes after null.
+ * (reg): vcmpequb result: v2 for 1st qw v3 for 2nd qw.
+ * Result placed at v2.
+ */
+# define FIND_NULL_POS(reg) \
+ vspltisb v11, -1; \
+ VADDUQM(v11, reg, v11); \
+ vandc v11, v11, reg; \
+ VPOPCNTD(v2, v11); \
+ vspltb v11, v2, 15; \
+ vcmpequb. v11, v11, v9; \
+ blt cr6, 1f; \
+ vsldoi v9, v0, v9, 1; \
+ vslo v2, v2, v9; \
+1: \
+ vsumsws v2, v2, v0;
+#else
+# define CALCULATE_MATCH() \
+ VBPERMQ(v6, v6, v10); \
+ MFVRD(r7, v6); \
+ addi r6, r7, -1; \
+ andc r6, r6, r7; \
+ popcntd r6, r6; \
+ subfic r6, r6, 15;
+# define FIND_NULL_POS(reg) \
+ VCLZD(v2, reg); \
+ vspltb v11, v2, 7; \
+ vcmpequb. v11, v11, v9; \
+ blt cr6, 1f; \
+ vsldoi v9, v0, v9, 1; \
+ vsro v2, v2, v9; \
+1: \
+ vsumsws v2, v2, v0;
+#endif /* !__LITTLE_ENDIAN__ */
+ .machine power7
+ENTRY (strrchr)
+ CALL_MCOUNT 2
+ dcbt 0,r3
+ clrrdi r8,r3,3 /* Align the address to doubleword boundary. */
+ cmpdi cr7,r4,0
+ ld r12,0(r8) /* Load doubleword from memory. */
+ li r9,0 /* used to store last occurence */
+ li r0,0 /* Doubleword with null chars to use
+ with cmpb. */
+
+ rlwinm r6,r3,3,26,28 /* Calculate padding. */
+
+ beq cr7,L(null_match)
+
+ /* Replicate byte to doubleword. */
+ insrdi r4,r4,8,48
+ insrdi r4,r4,16,32
+ insrdi r4,r4,32,0
+
+ /* r4 is changed now ,if its passed as more chars
+ check for null again */
+ cmpdi cr7,r4,0
+ beq cr7,L(null_match)
+ /* Now r4 has a doubleword of c bytes and r0 has
+ a doubleword of null bytes. */
+
+ cmpb r10,r12,r4 /* Compare each byte against c byte. */
+ cmpb r11,r12,r0 /* Compare each byte against null byte. */
+
+ /* Move the doublewords left and right to discard the bits that are
+ not part of the string and bring them back as zeros. */
+#ifdef __LITTLE_ENDIAN__
+ srd r10,r10,r6
+ srd r11,r11,r6
+ sld r10,r10,r6
+ sld r11,r11,r6
+#else
+ sld r10,r10,r6
+ sld r11,r11,r6
+ srd r10,r10,r6
+ srd r11,r11,r6
+#endif
+ or r5,r10,r11 /* OR the results to speed things up. */
+ cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
+ have been found. */
+ bne cr7,L(done)
+
+L(align):
+ andi. r12, r8, 15
+
+ /* Are we now aligned to a doubleword boundary? If so, skip to
+ the main loop. Otherwise, go through the alignment code. */
+
+ bne cr0, L(loop)
+
+ /* Handle WORD2 of pair. */
+ ldu r12,8(r8)
+ cmpb r10,r12,r4
+ cmpb r11,r12,r0
+ or r5,r10,r11
+ cmpdi cr7,r5,0
+ bne cr7,L(done)
+ b L(loop) /* We branch here (rather than falling through)
+ to skip the nops due to heavy alignment
+ of the loop below. */
+ .p2align 5
+L(loop):
+ /* Load two doublewords, compare and merge in a
+ single register for speed. This is an attempt
+ to speed up the null-checking process for bigger strings. */
+ ld r12,8(r8)
+ ldu r7,16(r8)
+ cmpb r10,r12,r4
+ cmpb r11,r12,r0
+ cmpb r6,r7,r4
+ cmpb r7,r7,r0
+ or r12,r10,r11
+ or r5,r6,r7
+ or r5,r12,r5
+ cmpdi cr7,r5,0
+ beq cr7,L(vector)
+
+ /* OK, one (or both) of the doublewords contains a c/null byte. Check
+ the first doubleword and decrement the address in case the first
+ doubleword really contains a c/null byte. */
+ cmpdi cr6,r12,0
+ addi r8,r8,-8
+ bne cr6,L(done)
+
+ /* The c/null byte must be in the second doubleword. Adjust the
+ address again and move the result of cmpb to r10 so we can calculate
+ the pointer. */
+
+ mr r10,r6
+ mr r11,r7
+ addi r8,r8,8
+
+ /* r10/r11 have the output of the cmpb instructions, that is,
+ 0xff in the same position as the c/null byte in the original
+ doubleword from the string. Use that to calculate the pointer. */
+
+L(done):
+ /* if there are more than one 0xff in r11, find the first pos of ff
+ in r11 and fill r10 with 0 from that position */
+ cmpdi cr7,r11,0
+ beq cr7,L(no_null)
+#ifdef __LITTLE_ENDIAN__
+ addi r3,r11,-1
+ andc r3,r3,r11
+ popcntd r0,r3
+#else
+ cntlzd r0,r11
+#endif
+ subfic r0,r0,63
+ li r6,-1
+#ifdef __LITTLE_ENDIAN__
+ srd r0,r6,r0
+#else
+ sld r0,r6,r0
+#endif
+ and r10,r0,r10
+L(no_null):
+#ifdef __LITTLE_ENDIAN__
+ cntlzd r0,r10 /* Count leading zeros before c matches. */
+ addi r3,r10,-1
+ andc r3,r3,r10
+ addi r10,r11,-1
+ andc r10,r10,r11
+ cmpld cr7,r3,r10
+ bgt cr7,L(no_match)
+#else
+ addi r3,r10,-1 /* Count trailing zeros before c matches. */
+ andc r3,r3,r10
+ popcntd r0,r3
+ cmpld cr7,r11,r10
+ bgt cr7,L(no_match)
+#endif
+ srdi r0,r0,3 /* Convert trailing zeros to bytes. */
+ subfic r0,r0,7
+ add r9,r8,r0 /* Return address of the matching c byte
+ or null in case c was not found. */
+ li r0,0
+ cmpdi cr7,r11,0 /* If r11 == 0, no null's have been found. */
+ beq cr7,L(align)
+
+ .align 4
+L(no_match):
+ mr r3,r9
+ blr
+
+/* Check the first 32B in GPR's and move to vectorized loop. */
+ .p2align 5
+L(vector):
+ addi r3, r8, 8
+ /* Make sure 32B aligned. */
+ andi. r10, r3, 31
+ bne cr0, L(loop)
+ vspltisb v0, 0
+ /* Precompute vbpermq constant. */
+ vspltisb v10, 3
+ lvsl v11, r0, r0
+ vslb v10, v11, v10
+ MTVRD(v1, r4)
+ li r5, 16
+ vspltb v1, v1, 7
+ /* Compare 32 bytes in each loop. */
+L(continue):
+ lvx v4, 0, r3
+ lvx v5, r3, r5
+ vcmpequb v2, v0, v4
+ vcmpequb v3, v0, v5
+ vcmpequb v6, v1, v4
+ vcmpequb v7, v1, v5
+ vor v8, v2, v3
+ vor v9, v6, v7
+ vor v11, v8, v9
+ vcmpequb. v11, v0, v11
+ addi r3, r3, 32
+ blt cr6, L(continue)
+ vcmpequb. v8, v0, v8
+ blt cr6, L(match)
+
+ /* One (or both) of the quadwords contains c/null. */
+ vspltisb v8, 2
+ vspltisb v9, 5
+ /* Precompute values used for comparison. */
+ vsl v9, v8, v9 /* v9 = 0x4040404040404040. */
+ vaddubm v8, v9, v9
+ vsldoi v8, v0, v8, 1 /* v8 = 0x80. */
+
+ /* Check if null is in second qw. */
+ vcmpequb. v11, v0, v2
+ blt cr6, L(secondqw)
+
+ /* Null found in first qw. */
+ addi r8, r3, -32
+ /* Calculate the null position. */
+ FIND_NULL_POS(v2)
+ /* Check if null is in the first byte. */
+ vcmpequb. v11, v0, v2
+ blt cr6, L(no_match)
+ vsububm v2, v8, v2
+ /* Mask unwanted bytes after null. */
+#ifdef __LITTLE_ENDIAN__
+ vslo v6, v6, v2
+ vsro v6, v6, v2
+#else
+ vsro v6, v6, v2
+ vslo v6, v6, v2
+#endif
+ vcmpequb. v11, v0, v6
+ blt cr6, L(no_match)
+ /* Found a match before null. */
+ CALCULATE_MATCH()
+ add r3, r8, r6
+ blr
+
+L(secondqw):
+ addi r8, r3, -16
+ FIND_NULL_POS(v3)
+ vcmpequb. v11, v0, v2
+ blt cr6, L(no_match1)
+ vsububm v2, v8, v2
+ /* Mask unwanted bytes after null. */
+#ifdef __LITTLE_ENDIAN__
+ vslo v7, v7, v2
+ vsro v7, v7, v2
+#else
+ vsro v7, v7, v2
+ vslo v7, v7, v2
+#endif
+ vcmpequb. v11, v0, v7
+ blt cr6, L(no_match1)
+ addi r8, r8, 16
+ vor v6, v0, v7
+L(no_match1):
+ addi r8, r8, -16
+ vcmpequb. v11, v0, v6
+ blt cr6, L(no_match)
+ /* Found a match before null. */
+ CALCULATE_MATCH()
+ add r3, r8, r6
+ blr
+
+L(match):
+ /* One (or both) of the quadwords contains a match. */
+ mr r8, r3
+ vcmpequb. v8, v0, v7
+ blt cr6, L(firstqw)
+ /* Match found in second qw. */
+ addi r8, r8, 16
+ vor v6, v0, v7
+L(firstqw):
+ addi r8, r8, -32
+ CALCULATE_MATCH()
+ add r9, r8, r6 /* Compute final length. */
+ b L(continue)
+/* We are here because strrchr was called with a null byte. */
+ .align 4
+L(null_match):
+ /* r0 has a doubleword of null bytes. */
+
+ cmpb r5,r12,r0 /* Compare each byte against null bytes. */
+
+ /* Move the doublewords left and right to discard the bits that are
+ not part of the string and bring them back as zeros. */
+#ifdef __LITTLE_ENDIAN__
+ srd r5,r5,r6
+ sld r5,r5,r6
+#else
+ sld r5,r5,r6
+ srd r5,r5,r6
+#endif
+ cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
+ have been found. */
+ bne cr7,L(done_null)
+
+ andi. r12, r8, 15
+
+ /* Are we now aligned to a quadword boundary? If so, skip to
+ the main loop. Otherwise, go through the alignment code. */
+
+ bne cr0, L(loop_null)
+
+ /* Handle WORD2 of pair. */
+ ldu r12,8(r8)
+ cmpb r5,r12,r0
+ cmpdi cr7,r5,0
+ bne cr7,L(done_null)
+ b L(loop_null) /* We branch here (rather than falling through)
+ to skip the nops due to heavy alignment
+ of the loop below. */
+
+ /* Main loop to look for the end of the string. Since it's a
+ small loop (< 8 instructions), align it to 32-bytes. */
+ .p2align 5
+L(loop_null):
+ /* Load two doublewords, compare and merge in a
+ single register for speed. This is an attempt
+ to speed up the null-checking process for bigger strings. */
+ ld r12,8(r8)
+ ldu r11,16(r8)
+ cmpb r5,r12,r0
+ cmpb r10,r11,r0
+ or r6,r5,r10
+ cmpdi cr7,r6,0
+ beq cr7,L(vector1)
+
+ /* OK, one (or both) of the doublewords contains a null byte. Check
+ the first doubleword and decrement the address in case the first
+ doubleword really contains a null byte. */
+
+ cmpdi cr6,r5,0
+ addi r8,r8,-8
+ bne cr6,L(done_null)
+
+ /* The null byte must be in the second doubleword. Adjust the address
+ again and move the result of cmpb to r10 so we can calculate the
+ pointer. */
+
+ mr r5,r10
+ addi r8,r8,8
+
+ /* r5 has the output of the cmpb instruction, that is, it contains
+ 0xff in the same position as the null byte in the original
+ doubleword from the string. Use that to calculate the pointer. */
+L(done_null):
+#ifdef __LITTLE_ENDIAN__
+ addi r0,r5,-1
+ andc r0,r0,r5
+ popcntd r0,r0
+#else
+ cntlzd r0,r5 /* Count leading zeros before the match. */
+#endif
+ srdi r0,r0,3 /* Convert trailing zeros to bytes. */
+ add r3,r8,r0 /* Return address of the matching null byte. */
+ blr
+/* Check the first 32B in GPR's and move to vectorized loop. */
+ .p2align 5
+L(vector1):
+ addi r3, r8, 8
+ /* Make sure 32B aligned. */
+ andi. r10, r3, 31
+ bne cr0, L(loop_null)
+ vspltisb v0, 0
+ /* Precompute vbpermq constant. */
+ vspltisb v10, 3
+ lvsl v11, r0, r0
+ vslb v10, v11, v10
+ li r5, 16
+ /* Compare 32 bytes in each loop. */
+L(continue1):
+ lvx v4, 0, r3
+ lvx v5, r3, r5
+ vcmpequb v2, v0, v4
+ vcmpequb v3, v0, v5
+ vor v8, v2, v3
+ vcmpequb. v11, v0, v8
+ addi r3, r3, 32
+ blt cr6, L(continue1)
+ addi r3, r3, -32
+ VBPERMQ(v2, v2, v10)
+ VBPERMQ(v3, v3, v10)
+ /* Shift each component into its correct position for merging. */
+#ifdef __LITTLE_ENDIAN__
+ vsldoi v3, v3, v3, 2
+#else
+ vsldoi v2, v2, v2, 6
+ vsldoi v3, v3, v3, 4
+#endif
+ /* Merge the results and move to a GPR. */
+ vor v4, v3, v2
+ MFVRD(r5, v4)
+#ifdef __LITTLE_ENDIAN__
+ addi r6, r5, -1
+ andc r6, r6, r5
+ popcntd r6, r6
+#else
+ cntlzd r6, r5 /* Count leading zeros before the match. */
+#endif
+ add r3, r3, r6 /* Compute final length. */
+ blr
+END (strrchr)
+weak_alias (strrchr, rindex)
+libc_hidden_builtin_def (strrchr)
--
2.7.4