Re: Kernel compression benchmarks

From: Alex Xu (Hello71)
Date: Wed Jul 01 2020 - 13:33:01 EST


Excerpts from Gao Xiang's message of July 1, 2020 11:50 am:
> Anyway, I think LZMA (xz) is still useful and which is more
> friendly to fixed-sized output compression than Zstd yet (But
> yeah, I'm not familar with all ZSTD internals. I will dig
> into that if I've more extra time).

Yes, I agree. If you look at the graphs, LZMA2 (xz/7zip) still produces
smaller results, even compared to zstd maximum settings, so definitely
LZMA2 should be kept, at least for now. I am only suggesting removing
LZMA, since it has no benefits over xz and zstd combination (bigger than
xz, slower than zstd).

>> - modern compressors (xz, lz4, zstd) decompress about as fast for each
>> compression level, only requiring more memory
>
> lz4 has fixed sliding window (dictionary, 64k), so it won't
> require more memory among different compression level when
> decompressing.

Yes, this is true. I tried to simplify among all compressors, but I
think I simplified too much. Thanks for clarifying.

Cheers,
Alex.