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| author | Adenilson Cavalcanti <adenilson.cavalcanti@arm.com> | 2019-11-21 23:04:38 +0000 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2019-11-21 23:04:38 +0000 |
| commit | 7c4128a124a812d086478e5c5f9f2f5893ab8871 (patch) | |
| tree | 9c903a3e86fec47ca8aebcd7741fe2aa29bc2d71 /deflate.c | |
| parent | e5c4d8c45ed18f84ea68f5029c9bceb1f67268b8 (diff) | |
| download | zlib-7c4128a124a812d086478e5c5f9f2f5893ab8871.tar.gz | |
Fix performance issue in RAW mode
While investigating the use of RAW mode, I noticed that it was *slower*
for compression than GZIP or ZLIB wrapper formats, which didn't make
sense (i.e. we don't calculate a data integrity check using RAW mode).
It turns out that the code was falling back to the portable implementation
of insert_string(), instead of using the optimized version that rely on 'crc32w'
as a hash function.
The reason is that CPU features detection is not triggered while using
RAW mode (i.e. we never call crc32() with a NULL buffer).
This patch fixes this issue ensuring that RAW mode is going to be faster
for both compression/decompression than either ZLIB or GZIP formats.
Bug: 833361
Change-Id: I285297f67ffc0114700ed03c2186ad21aab8b40e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1929634
Reviewed-by: Chris Blume <cblume@chromium.org>
Reviewed-by: Adenilson Cavalcanti <cavalcantii@chromium.org>
Commit-Queue: Adenilson Cavalcanti <cavalcantii@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#717877}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 171a0a69eb5d70f8a9f44000e26bc7dc65f1fd97
Diffstat (limited to 'deflate.c')
| -rw-r--r-- | deflate.c | 8 |
1 files changed, 8 insertions, 0 deletions
@@ -307,7 +307,15 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, int wrap = 1; static const char my_version[] = ZLIB_VERSION; + // Needed to activate optimized insert_string() that helps compression + // for all wrapper formats (e.g. RAW, ZLIB, GZIP). + // Feature detection is not triggered while using RAW mode (i.e. we never + // call crc32() with a NULL buffer). +#if defined(CRC32_ARMV8_CRC32) + arm_check_features(); +#elif defined(CRC32_SIMD_SSE42_PCLMUL) x86_check_features(); +#endif if (version == Z_NULL || version[0] != my_version[0] || stream_size != sizeof(z_stream)) { |