Re: Fast `guix environment --container' switch

[zimoun]

On Wed, 09 Dec 2020 at 11:55, Pierre Neidhardt <mail@ambrevar.xyz> wrote:
> `guix environment` incurs an overhead:
>
> --8<---------------cut here---------------start------------->8---
> time /gnu/store/a462kby1q51ndvxdv3b6p0rsixxrgx1h-hello-2.10/bin/hello
> Hello, world!
>
> real  0m0.002s
> user  0m0.002s
> sys   0m0.000s
> --8<---------------cut here---------------end--------------->8---
>
> --8<---------------cut here---------------start------------->8---
> $ time guix environment --ad-hoc hello -- hello
> Hello, world!
>
> real  0m0.921s
> user  0m1.003s
> sys   0m0.091s
> --8<---------------cut here---------------end--------------->8---
>
> It's possible to bypass this overhead by using --root:

It by-passes the computations of derivations and profiles.  Somehow,
using --root is using a precomputed profile. IIUC.

> So is it possible to use a similar trick to run something containerized
> "instantly", i.e.  with less than, say, 100ms overhead?

I see, you would like to be able to run a profile in container, right?
Somehow, it is similar to the wanted [1], IIUC.

1: <https://yhetil.org/guix-devel/877dvn10ro.fsf@dustycloud.org>


Cheers,
simon