Re: substitute derivation: also substitute grafts?

[Ricardo Wurmus]

Maxime Devos <maximedevos@telenet.be> writes:

> On 15-09-2022 16:46, Csepp wrote:
>> Ricardo Wurmus <rekado@elephly.net> writes:
>> 
>>> [...]
>>> Did I say *all items*? Well, … grafts are not included, because graft
>>> derivations are marked as not substitutable.
>>>
>>> Can we change that conditionally? I would really like to avoid having
>>> to build grafts on B when they have already been built on A.
>> I would love this too, because IO can be incredibly slow on HDDs and
>> large packages.  My netbook would be thankful.
>>
>
> There are some some opportunities for optimizations in the grafting
> code before substituting more -- for example, to avoid seek times, it
> would be possible to rewrite multiple files concurrently (maybe using
> 'par-for-each' to process each file in a directory in parallel).

While this is also an interesting development for grafts, my question is
much narrowed.  I’d be very happy if we could have a little switch that
made my daemon(s) ignore the “substitutable?” property and just
substitute everything.

I’m not looking for performance improvements in grafting, but in an
option to totally avoid doing the work twice when substituting a
derivation from a server in the same network.

-- 
Ricardo