[bug#39728] [PATCH] Allow parallel downloads and builds

[Julien Lepiller <julien@lepiller.eu>]

Le 25 février 2020 10:21:24 GMT-05:00, zimoun <zimon.toutoune@gmail.com> a écrit :
>Hi Julien,
>
>On Mon, 24 Feb 2020 at 22:43, Ludovic Courtès <ludo@gnu.org> wrote:
>> Julien Lepiller <julien@lepiller.eu> skribis:
>
>> > This patch allows to count builds and downloads separately. The
>idea is
>> > that downloads need bandwidth, but no CPU, while builds do not need
>> > bandwidth, but need CPU. With this patch, guix will be able to
>download
>> > substitutes while building unrelated packages. Currently, guix
>needs to
>> > wait for the download to finish before proceeding to the build.
>This
>> > should reduce the time of guix commands that need to build and
>download
>> > things at the same time.
>> >
>> > What do you think?
>>
>> I think it’s a good idea!
>>
>> I wonder what the UI will look like: (guix status) would no longer
>> display a progress bar when there’s more than on job (build or
>download)
>> taking place at the same time.
>
>Speaking about progress bar, it could be nice (as an improvement) to
>have a concurrent progress bar. As an example, see:
>
>http://hackage.haskell.org/package/concurrent-output
>
>
>> It would be great if you could test this patch for your daily usage. 
>I
>> find it surprisingly easy to break things in the daemon.  :-)
>
>How can I do that?
>After the 'make', how can change the daemon? And then revert it again
>to the default one?
>
>
>Cheers,
>simon

On the guix system, try (in a guix environment guix) sudo herd stop guix-daemon; sudo ./pre-inst-env guix-daemon --build-users-group=guixbuild 

To revert back, kill this (^C) and sudo herd start guix-daemon.