From 2676b89eb82f56825d7289edf21f17a6461388b7 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Wed, 30 May 2018 07:06:15 +0000 Subject: [PATCH] powerpc/lib: optimise PPC32 memcmp At the time being, memcmp() compares two chunks of memory byte per byte. This patch optimises the comparison by comparing word by word. On the same way as commit 15c2d45d17418 ("powerpc: Add 64bit optimised memcmp"), this patch moves memcmp() into a dedicated file named memcmp_32.S A small benchmark performed on an 8xx comparing two chuncks of 512 bytes performed 100000 times gives: Before : 5852274 TB ticks After: 1488638 TB ticks This is almost 4 times faster Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/lib/Makefile | 4 ++-- arch/powerpc/lib/memcmp_32.S | 45 ++++++++++++++++++++++++++++++++++++++++++++ arch/powerpc/lib/string.S | 17 ----------------- 3 files changed, 47 insertions(+), 19 deletions(-) create mode 100644 arch/powerpc/lib/memcmp_32.S diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile index 2c9b8c0..d0ca13a 100644 --- a/arch/powerpc/lib/Makefile +++ b/arch/powerpc/lib/Makefile @@ -26,14 +26,14 @@ obj-$(CONFIG_PPC_BOOK3S_64) += copyuser_power7.o copypage_power7.o \ memcpy_power7.o obj64-y += copypage_64.o copyuser_64.o mem_64.o hweight_64.o \ - memcpy_64.o memcmp_64.o pmem.o + memcpy_64.o pmem.o obj64-$(CONFIG_SMP) += locks.o obj64-$(CONFIG_ALTIVEC) += vmx-helper.o obj64-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o obj-y += checksum_$(BITS).o checksum_wrappers.o \ - string_$(BITS).o + string_$(BITS).o memcmp_$(BITS).o obj-y += sstep.o ldstfp.o quad.o obj64-y += quad.o diff --git a/arch/powerpc/lib/memcmp_32.S b/arch/powerpc/lib/memcmp_32.S new file mode 100644 index 0000000..5010e37 --- /dev/null +++ b/arch/powerpc/lib/memcmp_32.S @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * memcmp for PowerPC32 + * + * Copyright (C) 1996 Paul Mackerras. + * + */ + +#include +#include + + .text + +_GLOBAL(memcmp) + srawi. r7, r5, 2 /* Divide len by 4 */ + mr r6, r3 + beq- 3f + mtctr r7 + li r7, 0 +1: lwzx r3, r6, r7 + lwzx r0, r4, r7 + addi r7, r7, 4 + cmplw cr0, r3, r0 + bdnzt eq, 1b + bne 5f +3: andi. r3, r5, 3 + beqlr + cmplwi cr1, r3, 2 + blt- cr1, 4f + lhzx r3, r6, r7 + lhzx r0, r4, r7 + addi r7, r7, 2 + subf. r3, r0, r3 + beqlr cr1 + bnelr +4: lbzx r3, r6, r7 + lbzx r0, r4, r7 + subf. r3, r0, r3 + blr +5: li r3, 1 + bgtlr + li r3, -1 + blr +EXPORT_SYMBOL(memcmp) diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S index 5343a88..4b41970 100644 --- a/arch/powerpc/lib/string.S +++ b/arch/powerpc/lib/string.S @@ -54,23 +54,6 @@ _GLOBAL(strncmp) blr EXPORT_SYMBOL(strncmp) -#ifdef CONFIG_PPC32 -_GLOBAL(memcmp) - PPC_LCMPI 0,r5,0 - beq- 2f - mtctr r5 - addi r6,r3,-1 - addi r4,r4,-1 -1: lbzu r3,1(r6) - lbzu r0,1(r4) - subf. r3,r0,r3 - bdnzt 2,1b - blr -2: li r3,0 - blr -EXPORT_SYMBOL(memcmp) -#endif - _GLOBAL(memchr) PPC_LCMPI 0,r5,0 beq- 2f -- 2.7.4