Repeated the #compression #benchmark with the same file on a beefier machine (AMD Ryzen 9 5950X), results are quite identical, except faster overall.
This plot is also interesting:
- #gzip and #lz4 have fixed (!) and very low RAM usage across levels and compression/decompression - #xz RAM usage scales with the level from a couple of MBs (0) to nearly a GB (9) - #zstd RAM usage scales weirdly with level but not as extreme as #xz
First let's look only at the non-fancy options (no --fast or multithreading) and make log-log plots to better see what's happening in the 'clumps' of points. Points of interest for me:
- #gzip has a *really* low memory footprint across all compression levels - #zstd clearly wins the decompression speed/compression ratio compromise! - #xz at higher levels is unrivalled in compression ratio - #lz4 higher levels aren't worth it. #lz4 is also just fast.
⏱️ Compression vs Decompression speed. Interesting that #zstd has some settings that actually decompress slower than they compress. Might just be my machine, though... #xz is still a turtle 🐢, #gzip is not much better, #lz4 decompresses much faster than is compressed, #zstd again has something for everybody.
My conclusion after all this is that I'll probably use #zstd level 1 (not the default level 3!) for #compression of my #CSV measurement data from now on:
- ultra fast compression and decompression, on par with #lz4 - nearly as good a compression ratio as #gzip level 9 - negligible RAM usage
When I need ultra small files though, e.g. for transfer over a slow connection, I'll keep using #xz level 9.
