Re: How/When will guix pull stop to compile the 616 files?

[Ricardo Wurmus <rekado@elephly.net>]

Jack Hill <jackhill@jackhill.us> writes:

> On Tue, 8 Aug 2017, Ricardo Wurmus wrote:
>
>>
>> Paul Dufresne <dufresnep@gmail.com> writes:
>>
>>> It takes 45 mins. on my relatively old dual core to guix-pull
>>
>> Yeah, this isn’t great.  Since 0.13.0 compilation is slower and requires
>> a whole lot more memory.  That’s a known problem.
>>
>> There are some ideas to reduce the amount of compilation that has to
>> happen locally, but it isn’t quite as simple as a first look may
>> suggest.
>
> Could building be avoided entirely with substitutes? Are substitutes not
> appropriate for some reason, or is it just that substitutes are not
> produced on Hydra for every guix commit?

Before a substitute can be requested, Guix will have to compute a
derivation locally.  In the case of Guix itself this is rather
expensive.

Once we have the derivation we can ask substitute servers if they have a
binary substitute for performing the work the derivation describes.

So, local *computation* cannot be avoided, but local building should be
avoidable for most packages — here the problem is that hydra isn’t fast
enough yet.  I’ve been preparing an alternative build farm at the
institute where I work, which will hopefully soon be powerful enough to
build packages more quickly than our current Hydra does.

--
Ricardo

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