Re: Fast `guix environment --container' switch

[zimoun]

Hi Pierre,

On Wed, 09 Dec 2020 at 10:40, Pierre Neidhardt <mail@ambrevar.xyz> wrote:

> `guix environment --container ... -- my-foo-program` is great but a bit
> slow to start.
>
> Is there a way to speed this up?

I get, cold cache:

--8<---------------cut here---------------start------------->8---
$ sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'
$ time guix environment --container --ad-hoc hello -- hello
Hello, world!

real    0m2.815s
user    0m1.852s
sys     0m0.238s

$ sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'
$ time guix environment --pure --ad-hoc hello -- hello
Hello, world!

real    0m2.656s
user    0m1.733s
sys     0m0.240s
--8<---------------cut here---------------end--------------->8---

and warm cache:

--8<---------------cut here---------------start------------->8---
$ time guix environment --container --ad-hoc hello -- hello
Hello, world!

real    0m1.399s
user    0m1.544s
sys     0m0.104s

$ time guix environment --pure --ad-hoc hello -- hello
Hello, world!

real    0m1.250s
user    0m1.492s
sys     0m0.094s
--8<---------------cut here---------------end--------------->8---


Do you have examples where the difference is significant?


All the best,
simon