diff options
author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-08-01 09:01:14 +0000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-08-07 21:49:30 +1000 |
commit | 9412b234501eef1d273cc759387a232f0027c574 (patch) | |
tree | fe37ba51c94c5a3f18b885000f8aa4cb589fbd31 /arch/powerpc/include/asm | |
parent | f0abbfd89fed4abd8301b35fbf65a26d85b16e7f (diff) |
powerpc/lib: Implement strlen() in assembly for PPC32
The generic implementation of strlen() reads strings byte per byte.
This patch implements strlen() in assembly based on a read of entire
words, in the same spirit as what some other arches and glibc do.
On a 8xx the time spent in strlen is reduced by 3/4 for long strings.
strlen() selftest on an 8xx provides the following values:
Before the patch (ie with the generic strlen() in lib/string.c):
len 256 : time = 1.195055
len 016 : time = 0.083745
len 008 : time = 0.046828
len 004 : time = 0.028390
After the patch:
len 256 : time = 0.272185 ==> 78% improvment
len 016 : time = 0.040632 ==> 51% improvment
len 008 : time = 0.033060 ==> 29% improvment
len 004 : time = 0.029149 ==> 2% degradation
On a 832x:
Before the patch:
len 256 : time = 0.236125
len 016 : time = 0.018136
len 008 : time = 0.011000
len 004 : time = 0.007229
After the patch:
len 256 : time = 0.094950 ==> 60% improvment
len 016 : time = 0.013357 ==> 26% improvment
len 008 : time = 0.010586 ==> 4% improvment
len 004 : time = 0.008784
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm')
-rw-r--r-- | arch/powerpc/include/asm/string.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h index 9b8cedf618f4..1647de15a31e 100644 --- a/arch/powerpc/include/asm/string.h +++ b/arch/powerpc/include/asm/string.h @@ -50,6 +50,8 @@ static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n) return __memset64(p, v, n * 8); } #else +#define __HAVE_ARCH_STRLEN + extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); #endif #endif /* __KERNEL__ */ |