From 1128bb7813a896bd608fb622eee3c26aaf33b473 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 18 May 2018 15:01:16 +0200 Subject: powerpc/lib: Adjust .balign inside string functions for PPC32 commit 87a156fb18fe1 ("Align hot loops of some string functions") degraded the performance of string functions by adding useless nops A simple benchmark on an 8xx calling 100000x a memchr() that matches the first byte runs in 41668 TB ticks before this patch and in 35986 TB ticks after this patch. So this gives an improvement of approx 10% Another benchmark doing the same with a memchr() matching the 128th byte runs in 1011365 TB ticks before this patch and 1005682 TB ticks after this patch, so regardless on the number of loops, removing those useless nops improves the test by 5683 TB ticks. Fixes: 87a156fb18fe1 ("Align hot loops of some string functions") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/cache.h | 3 +++ arch/powerpc/lib/string.S | 7 ++++--- 2 files changed, 7 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/powerpc/include/asm/cache.h b/arch/powerpc/include/asm/cache.h index c1d257aa4c2d3..66298461b640f 100644 --- a/arch/powerpc/include/asm/cache.h +++ b/arch/powerpc/include/asm/cache.h @@ -9,11 +9,14 @@ #if defined(CONFIG_PPC_8xx) || defined(CONFIG_403GCX) #define L1_CACHE_SHIFT 4 #define MAX_COPY_PREFETCH 1 +#define IFETCH_ALIGN_SHIFT 2 #elif defined(CONFIG_PPC_E500MC) #define L1_CACHE_SHIFT 6 #define MAX_COPY_PREFETCH 4 +#define IFETCH_ALIGN_SHIFT 3 #elif defined(CONFIG_PPC32) #define MAX_COPY_PREFETCH 4 +#define IFETCH_ALIGN_SHIFT 3 /* 603 fetches 2 insn at a time */ #if defined(CONFIG_PPC_47x) #define L1_CACHE_SHIFT 7 #else diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S index a787776822d86..0378def28d411 100644 --- a/arch/powerpc/lib/string.S +++ b/arch/powerpc/lib/string.S @@ -12,6 +12,7 @@ #include #include #include +#include .text @@ -23,7 +24,7 @@ _GLOBAL(strncpy) mtctr r5 addi r6,r3,-1 addi r4,r4,-1 - .balign 16 + .balign IFETCH_ALIGN_BYTES 1: lbzu r0,1(r4) cmpwi 0,r0,0 stbu r0,1(r6) @@ -43,7 +44,7 @@ _GLOBAL(strncmp) mtctr r5 addi r5,r3,-1 addi r4,r4,-1 - .balign 16 + .balign IFETCH_ALIGN_BYTES 1: lbzu r3,1(r5) cmpwi 1,r3,0 lbzu r0,1(r4) @@ -77,7 +78,7 @@ _GLOBAL(memchr) beq- 2f mtctr r5 addi r3,r3,-1 - .balign 16 + .balign IFETCH_ALIGN_BYTES 1: lbzu r0,1(r3) cmpw 0,r0,r4 bdnzf 2,1b -- cgit v1.2.3