[bug#43340] [PATCH 0/5] Speed up archive export/import

[Mathieu Othacehe]

Hey Ludo,

>> Specifically, it implements option #4 (spawning ‘guix authenticate’
>> once for the whole session, instead of spawning it every time a
>> store item needs to be signed or authenticated), achieving a ~15x
>> speedup, which is not bad.  :-)

Woo, congrats!

> Below is the new Gantt chart for:
>
>   perf timechart record guix archive --export -r $(guix build coreutils -d) 
> -v3 >/tmp/dump
>
> Most of the work happens in ‘guix authenticate’.

I never used the "timechart" sub-command but it sounds really
nice. Regarding the option you chose, I think it's the more appropriate
right now. It's very delicate to dedicate time and effort to tweak
guix-daemon and how we use it, having in mind that we'd like to get rid
of it.

However, the potential short term gains can be so huge, that for now
it's the best thing to do. I should just do like you, and dive into it
to see what can be done for contention and locking when using
'build-paths' RPC via Cuirass.

In the meantime, a short review that I hope to complete next week.

Thanks for your efforts,

Mathieu