From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?UTF-8?Q?Court=C3=A8s?=)
Subject: bug#27284: [PATCH 1/8] build: Factorize module compilation in (guix
	build compile).
Date: Sun, 22 Oct 2017 19:51:14 -0700
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To: Eric Bavier <ericbavier@centurylink.net>
Cc: 27284@debbugs.gnu.org, Maxim Cournoyer <maxim.cournoyer@gmail.com>

Heya,

Eric Bavier <ericbavier@centurylink.net> skribis:

> And from NEWS for the 4.2 release:
>
> * The amount of parallelism can be determined by querying MAKEFLAGS, even=
 when
>   the job server is enabled (previously MAKEFLAGS would always contain on=
ly
>   "-j", with no number, when job server was enabled).

Thanks for digging!  I didn=E2=80=99t expect such things to ever change.

> It Would Be Nice if the functionality worked for older versions of make
> that people might have on their systems.

With the patch I posted, Scheme compilation would always use one thread
per core, which is what it currently does in =E2=80=98master=E2=80=99.

That=E2=80=99s in argument in favor of the lazy in me: it=E2=80=99s an impr=
ovement for
people using a reasonably recent system, and it=E2=80=99s not a regression =
for
the others!  :-)

WDYT?

> Using the jobserver directly would require quite a bit of work for the
> current patch set, but I wonder if there is another way to determine
> the -jN parameter for make<4.2 that we could use.  Maybe simply
> polling the jobserver fds at the start?

AIUI the job server does not reveal how many jobs are allowed.  It
merely grants you an execution token.

Or did you have something else in mind?

Thanks,
Ludo=E2=80=99.