Parallel (de-)compression

[Andreas Enge]

Hello,

on my relatively slow ARM build machine with relatively fast storage (SSD),
I notice that often there is an xz process taking 100% of CPU, while there
is never more than 20MB/s written to disk. For instance, texlive-texmf
takes a very long time to build and install into the store.

Would it make sense to switch to a parallel (de-)compression tool to leverage
higher numbers of cores? We have pbzip2 already in Guix, which is compatible
with bzip2.

As a negative point, we would increase the size of our packages and also the
bandwidth requirement. So maybe this is not worth it, since we could also
build more packages in parallel. Or are there parallel implementations of xz?

Andreas