Add ZSTD_HASH_USE_CRC32C to use an optimized hash#4611
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danlark1 wants to merge 3 commits intofacebook:devfrom
Open
Add ZSTD_HASH_USE_CRC32C to use an optimized hash#4611danlark1 wants to merge 3 commits intofacebook:devfrom
danlark1 wants to merge 3 commits intofacebook:devfrom
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At Google we found 3-5% improvement for densely compressed data when using CRC32C and low bits of its hash. Most uplift should be seen with at least `-msse4.2` flag for x86-64 and march=armv8-a+crc extension (from Arm8.3 CRC is mandatory). In this patch we added a macro, fixed implementation details which relied on shifts and added CI tests with different configurations. We also added a crc32c regression test to compare sizes and verify it's not regressing the values too much.
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At Google we found 3-5% improvement for densely
compressed data when using CRC32C and low bits
of its hash.
Most uplift should be seen with at least
-msse4.2flagfor x86-64 and march=armv8-a+crc extension
(from Arm8.3 CRC is mandatory).
In this patch we added a macro, fixed implementation
details which relied on shifts and added CI tests with
different configurations. We also added a crc32c
regression test to compare sizes and verify it's not
regressing the values too much.