bug#24937: "deleting unused links" GC phase is too slow

[Ludovic Courtès]

Hi Ricardo,

Thanks for running this benchmark!

Ricardo Wurmus <address@hidden> skribis:

>   root@hydra-guix-127 ~# ls -1 /gnu/store/.links | wc -l
>   2017395

That’s not a lot, my laptop has 2.8M links.

It’s interesting to see that system time remains at ~4.2s in all modes.
So the only thing that modes 2 and 3 achieve is increasing CPU time.
It’s as if the order in which files are stat’d had no impact on I/O
performance.

Ludo’.