Re: wip-ungrafting builds stuck

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi,

Mark H Weaver <mhw@netris.org> writes:

> Mathieu Othacehe <othacehe@gnu.org> writes:
>
>>> Any idea what could be wrong, Mathieu?  What would you suggest to do
>>> when investigating such issues?
>>
>> Yes I noticed it. The main problem here is that almost all workers are
>> stuck building Rust.
>>
>> I see two actions here:
>>
>> 1. Understand why Rust is taking so long to build.
>
> The attached patch, which I've been using on my private branch of Guix
> for a long time and is fully tested, would significantly speed up the
> Rust bootstrap.  I never submitted it because I wasn't sure it would be
> of interest.
>
>        Mark

FWIW, the tests are already disabled on core-updates, which reduced the
build time by 33%.  Also we now bootstrap from 1.29 there instead of
1.19.  The net result is a 50% faster bootstrap (8 hours) compared to
master (16 hours) on a 3900X Ryzen processor.  That's still a lot of
time.  I hope that the effort to produce a GCC front end for Rust
succeeds [0].  Otherwise mrustc, which we already use to bootstrap rust,
is now able to bootstrap from 1.39 (unreleased yet though), so we should
look into making use of it [1].

Maxim

[0]  https://github.com/Rust-GCC/gccrs
[1]  https://github.com/thepowersgang/mrustc/