Re: parallelizing more actions

[Ludovic Courtès]

Hi Efraim,

Efraim Flashner <address@hidden> skribis:

> While rebuilding glibc-final on aarch64 I realized that the 'strip phase
> took 235 seconds. The relevant code for 'strip from gnu-build-system is
> in guix/build/gnu-build-system.scm, starting at line 340, with the
> actual stripping starting at 398. When I changed 'for-each' to
> 'par-for-each' the time dropped from 235 seconds to 215, about an 8.5%
> savings. I'm pretty sure most of that time was spent failing to strip
> certain files, but it is still a savings.

Is it on a spinning hard disk or an SSD?  My guess is that most of the
time is I/O, and that parallelizing doesn’t buy us much (indeed, 8.5% is
not that much, far from a linear speedup.) 

So I’m mildly reluctant to parallelizing this particular piece of code.

Thanks,
Ludo’.