termux-backup is very slow due to compression being single-threaded

[navid-zamani]

When using termux-backup somewhere.tar.bz2 (or the same with .xz or the like), it takes surprisingly long.

Looking at adb shell top, I noticed that bzip2 only uses a single core.

So I kindly request changing that to use all cores. (Which in my case would make it take 1/8th of the time!)

At least for compression formats with parallel support (like xz -T), or even those with a separate parallel version.

[navid-zamani]

P.S.: As a quick workaround for those looking for a solution right now, try this:
termux-backup - | pv | xz -z -T0 -c - > somewhere.tar.xz