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From: =?utf-8?Q?Ludovic_Court=C3=A8s?= <ludo@gnu.org>
Subject: Re: Performance improvements
Date: Mon, 28 Oct 2019 00:06:25 +0100
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In-Reply-To: <87r23fknvz.fsf@gnu.org> ("Ludovic
 \=\?utf-8\?Q\?Court\=C3\=A8s\=22'\?\=
 \=\?utf-8\?Q\?s\?\= message of "Mon, 14 Oct 2019 23:39:28 +0200")
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To: Guix-devel <Guix-devel@gnu.org>

Hi!

Some more improvements come from these commits:

  ac19950507 gnu: bootstrap: Cache the 'bootstrap-executable' origins.
  5166d02730 gnu: bootstrap: 'bootstrap-origin' preserves eq?-ness when no =
changes are made.
  d727a9343d derivations: Don't memoize 'derivation->bytevector'.
  f5fca9a82c gexp: Cache the module to derivation mappings.
  c57e417eff store: Allow objects in the cache to be inserted and search fo=
r with 'equal?'.
  f58b45350b gexp: Add 'imported+compiled-modules'.
  f726f6f802 derivations: 'build-expression->derivation' caches its module =
derivations.
  cf7648f882 derivations: Introduce 'imported+compiled-modules'.

This caches the module-to-derivation mapping, which wasn=E2=80=99t cached u=
ntil
now.

Overall the goal is to have the high-level caches work nicely (the
=E2=80=9Cobject cache=E2=80=9D in particular), rendering the low-level cach=
es (such as
the =E2=80=98add-data-to-store=E2=80=99 cache) potentially useless.  This i=
s beneficial
because a cache hit on the object cache saves more CPU time than a cache
hit on a low-level cache.

Ludovic Court=C3=A8s <ludo@gnu.org> skribis:

> $ time guix build libreoffice -nd
> /gnu/store/8drmbhsrayr2j5lkvrwq37rg8g06hgsw-libreoffice-6.1.5.2.drv
>
> real    0m2.142s
> user    0m2.323s
> sys     0m0.082s
> $ guix describe
> Generacio 110   Oct 14 2019 08:43:33    (nuna)
>   guix bd04fe8
>     repository URL: https://git.savannah.gnu.org/git/guix.git
>     branch: master
>     commit: bd04fe878627a14533d908ccdf5b906050d6e0a4

And now:

--8<---------------cut here---------------start------------->8---
$ time /tmp/new/bin/guix build libreoffice -nd
/gnu/store/ibzap0v1c367h0j2mdd2jmlsfx9jplfb-libreoffice-6.1.5.2.drv

real    0m1.658s
user    0m1.699s
sys     0m0.073s
$ /tmp/new/bin/guix describe
Generacio 1     Oct 28 2019 00:03:05    (nuna)
  guix 271b3c9
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: 271b3c9d16f8880f4a27b52a615cdec611322fae
--8<---------------cut here---------------end--------------->8---

Ludo=E2=80=99.