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

[zimoun <zimon.toutoune@gmail.com>]

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