From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: guix-devel <guix-devel@gnu.org>
Subject: Re: Dependency cycle issues when using a Gexp-based snippet
Date: Mon, 14 Sep 2020 12:55:10 -0400 [thread overview]
Message-ID: <87tuw047td.fsf@gmail.com> (raw)
In-Reply-To: <877dt6orwn.fsf@gnu.org> ("Ludovic Courtès"'s message of "Mon, 07 Sep 2020 11:30:32 +0200")
Hello Ludovic,
[...]
>> What is the difference between delayed and thunked? Would a thunked
>> capture the closure of its environment while delayed not? Is the
>> closure useful to access record-bound values such as the version field
>> of a package?
>
> ‘Thunk’ uses an actual thunk (zero-argument procedure) that’s called
> each time the field is accessed; ‘delayed’ uses a promise, which is
> similar except that the result is memoized (info "(guile) Delayed
> Evaluation").
Thanks for the explanation! Now I wonder why delayed should not always
be preferable to thunks? Is there a reason to offer thunked as well?
[...]
> What would be interesting is a comparison of the performance of
> ‘package-derivation’, which can be done with something like:
>
> time guix build -d --no-grafts libreoffice pandoc
>
> For memory consumption, try:
>
> GUIX_PROFILING=gc guix build -d --no-grafts libreoffice pandoc
Thanks for these "benchmarking" tips :-). Unfortunately, making the
'snippet' field either thunked or delayed causes 'guix build' to stop
working entirely, peaking the CPU and slowy eating RAM away (looks like
a typical dependency cycle).
I'm at a lost as to how this can be debugged.
That's unfortunate, because as it stands, Gexp-based snippets don't seem
very usable.
Thank you,
Maxim
next prev parent reply other threads:[~2020-09-14 16:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-24 2:10 Dependency cycle issues when using a Gexp-based snippet maxim.cournoyer
2020-08-24 21:09 ` Ludovic Courtès
2020-09-02 15:08 ` Maxim Cournoyer
2020-09-07 9:30 ` Ludovic Courtès
2020-09-14 16:55 ` Maxim Cournoyer [this message]
2020-09-16 10:08 ` Ludovic Courtès
2020-09-07 18:30 ` Mark H Weaver
2020-09-16 10:00 ` Ludovic Courtès
2020-09-08 4:07 ` What should "guix build --source" produce? (was Re: Dependency cycle issues when using a Gexp-based snippet) Mark H Weaver
2020-09-08 7:22 ` Andreas Enge
2020-09-11 18:22 ` Maxim Cournoyer
2020-09-11 18:42 ` zimoun
2020-09-11 20:40 ` Andreas Enge
2020-09-11 18:26 ` Maxim Cournoyer
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