From 6acf22a17991e3e98c35596f0b1cedfaebed6ec3 Mon Sep 17 00:00:00 2001 From: Grazvydas Ignotas Date: Fri, 29 Dec 2017 02:05:05 +0200 Subject: [PATCH] util: use faster zlib's CRC32 implementaion MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit zlib provides a faster slice-by-4 CRC32 implementation than the traditional single byte lookup one used by mesa. As most supported platforms now link zlib unconditionally, we can easily use it. Improvement for a 1MB buffer (avg MB/s, n=100, zlib 1.2.8): i5-6600K C2D E4500 mesa zlib mesa zlib 443 1443 225% +/- 2.1% 403 1175 191% +/- 0.9% It has been verified the calculation results stay the same after this change. Signed-off-by: Grazvydas Ignotas Reviewed-by: Eric Engestrom Reviewed-by: Marek Olšák Reviewed-by: Ian Romanick --- src/util/crc32.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/src/util/crc32.c b/src/util/crc32.c index f2e01c61e58..425046ab5fd 100644 --- a/src/util/crc32.c +++ b/src/util/crc32.c @@ -33,6 +33,9 @@ */ +#ifdef HAVE_ZLIB +#include +#endif #include "crc32.h" @@ -114,6 +117,16 @@ util_hash_crc32(const void *data, size_t size) const uint8_t *p = data; uint32_t crc = 0xffffffff; +#ifdef HAVE_ZLIB + /* Prefer zlib's implementation for better performance. + * zlib's uInt is always "unsigned int" while size_t can be 64bit. + * Since 1.2.9 there's crc32_z that takes size_t, but use the more + * available function to avoid build system complications. + */ + if ((uInt)size == size) + return ~crc32(0, data, size); +#endif + while (size--) crc = util_crc32_table[(crc ^ *p++) & 0xff] ^ (crc >> 8); -- 2.30.2