com php-src: opcache: Patch SSE based fast_memcpy() imp lementation: ext/opcache/zend_accelerator_util_funcs .c

Commit: 68185bafbe2c7ab025703917d259c4c19ce456eb Author: Bogdan Andone <bogdan.andone@intel.com> Wed, 29 Jul 2015 14:19:04 +0300 Parents: 4e66cce87ce0e57a7394486412e61abcfc5f3520 Branches: master Link: http://git.php.net/?p=php-src.git;a=commitdiff;h=68185bafbe2c7ab025703917d259c4c19ce456eb Log: opcache: Patch SSE based fast_memcpy() implementation Use _mm_store_si128() instead of _mm_stream_si128(). This ensures that copied memory is preserved in data cache, which is good as the interpretor will start to use this data without the need to go back to memory. _mm_stream* is intended to be used for stores where we want to avoid reading data into the cache and the cache pollution; in our scenario it seems that preserving the data in cache has a positive impact. Tests on WordPress 4.1 show ~1% performance increase with fast_memcpy() in place versus standard memcpy() when running php-cgi -T10000 wordpress/index.php. I also updated SW prefetching on target memory but its contribution is almost negligible. The address to be prefetched will be used in a couple of cycles (at the next iteration) while the data from memory will be available in >100 cycles. Changed paths: M ext/opcache/zend_accelerator_util_funcs.c Diff: diff --git a/ext/opcache/zend_accelerator_util_funcs.c b/ext/opcache/zend_accelerator_util_funcs.c index e20f3d1..cfb03a0 100644 --- a/ext/opcache/zend_accelerator_util_funcs.c +++ b/ext/opcache/zend_accelerator_util_funcs.c @@ -658,16 +658,17 @@ static zend_always_inline void fast_memcpy(void *dest, const void *src, size_t s do { _mm_prefetch(dqsrc + 4, _MM_HINT_NTA); + _mm_prefetch(dqdest + 4, _MM_HINT_T0); __m128i xmm0 = _mm_load_si128(dqsrc + 0); __m128i xmm1 = _mm_load_si128(dqsrc + 1); __m128i xmm2 = _mm_load_si128(dqsrc + 2); __m128i xmm3 = _mm_load_si128(dqsrc + 3); dqsrc += 4; - _mm_stream_si128(dqdest + 0, xmm0); - _mm_stream_si128(dqdest + 1, xmm1); - _mm_stream_si128(dqdest + 2, xmm2); - _mm_stream_si128(dqdest + 3, xmm3); + _mm_store_si128(dqdest + 0, xmm0); + _mm_store_si128(dqdest + 1, xmm1); + _mm_store_si128(dqdest + 2, xmm2); + _mm_store_si128(dqdest + 3, xmm3); dqdest += 4; } while (dqsrc != end); }