sapling/lib/lz4-pyframe
Jun Wu 22e9000fc9 lz4-pyframe: add compresshc
Summary:
Unfortunately required symbols are not exposed by lz4-sys. So we just declare
them ourselves.

Make sure it compresses better:

  In [1]: c=open('/bin/bash').read();
  In [2]: from mercurial.rust import lz4
  In [3]: len(lz4.compress(c))
  Out[3]: 762906
  In [4]: len(lz4.compresshc(c))
  Out[4]: 626970

While it's much slower for larger data (and compresshc is slower than pylz4):

  Benchmarking (easy to compress data, 20MB)...
            pylz4.compress: 10328.03 MB/s
       rustlz4.compress_py:  9373.84 MB/s
          pylz4.compressHC:  1666.80 MB/s
     rustlz4.compresshc_py:  8298.57 MB/s
          pylz4.decompress:  3953.03 MB/s
     rustlz4.decompress_py:  3935.57 MB/s
  Benchmarking (hard to compress data, 0.2MB)...
            pylz4.compress:  4357.88 MB/s
       rustlz4.compress_py:  4193.34 MB/s
          pylz4.compressHC:  3740.40 MB/s
     rustlz4.compresshc_py:  2730.71 MB/s
          pylz4.decompress:  5600.94 MB/s
     rustlz4.decompress_py:  5362.96 MB/s
  Benchmarking (hard to compress data, 20MB)...
            pylz4.compress:  5156.72 MB/s
       rustlz4.compress_py:  5447.00 MB/s
          pylz4.compressHC:    33.70 MB/s
     rustlz4.compresshc_py:    22.25 MB/s
          pylz4.decompress:  2375.42 MB/s
     rustlz4.decompress_py:  5755.46 MB/s

Note python-lz4 was using an ancient version of lz4. So there could be differences.

Reviewed By: DurhamG

Differential Revision: D13528200

fbshipit-source-id: 6be1c1dd71f57d40dcffcc8d212d40a853583254
2018-12-20 17:54:22 -08:00
..
benches lz4-pyframe: add a benchmark 2018-12-20 17:54:21 -08:00
src lz4-pyframe: add compresshc 2018-12-20 17:54:22 -08:00
Cargo.toml lz4-pyframe: add compresshc 2018-12-20 17:54:22 -08:00