bug#27780: guix environment to build guile from git required excessive CPU time

[Maxim Cournoyer]

Hello Mark,

ludo@gnu.org (Ludovic Courtès) writes:

> Hi Mark,
>
> Mark H Weaver <mhw@netris.org> skribis:
>
>> I just ran the following command on my Thinkpad X200 running GuixSD:
>>
>>   ./pre-inst-env guix environment guile --ad-hoc autoconf automake libtool 
>> flex gettext
>>
>> Using the guix client from a git checkout at v0.13.0-1496-gcfd6a3b1e,
>> and using guix-daemon from guix-0.13.0-3.b547349.
>>
>> This command took approximately 20 minutes of CPU time before
>> downloading anything except possibly some NARINFOs.  During this initial
>> 20 minutes of CPU-bound activity, the only output was 4 occurrences of
>> the following message:
>>
>> substitute: updating list of substitutes from 
>> 'https://mirror.hydra.gnu.org'... 100.0%
>>
>> The CPU time was roughly evenly split between the following two
>> processes:
>>
>> USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
>> root 8456 57.0 0.1 37420 7788 ?  Rs 22:27 11:31 \_
>> /gnu/store/gkv8zl774h2qpa89mrf6d74fry3rsnpa-guix-0.13.0-3.b547349/bin/guix-daemon
>> 8450 guixbuild --max-silent-time 0 --timeout 0 --substitute-urls
>> https://mirror.hydra.gnu.org --gc-keep-derivations=yes
>> --gc-keep-outputs=yes
>> root 8457 45.0 0.9 124040 38556 ?  Rl 22:27 9:03 \_
>> /gnu/store/z16li2znnk2pdgrg3ldm34k669pcrdcx-guile-2.2.2/bin/guile
>> --no-auto-compile
>> /gnu/store/gkv8zl774h2qpa89mrf6d74fry3rsnpa-guix-0.13.0-3.b547349/bin/.guix-real
>> substitute --query
>
> Is it reproducible?  If/when that happens again, could you ‘strace’ the
> ‘guix substitute’ process?
>
> Any idea whether hydra.gnu.org was loaded at the time and returning 504
> (“Gateway Timeout”)?
>
> Thanks,
> Ludo’.

Any update on this?  If that's not an issue anymore, feel free to close
it, otherwise I'll do so in 2 weeks time.

Thank you,

Maxim