Fwd: Building Guile with ‘-j1’?

Fwd: Building Guile with ‘-j1’?

[Leo Prikler]

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Messed up ML address.

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From: Leo Prikler <leo.prikler@student.tugraz.at>
To: ludo@gnu.org
Cc: guix-devel@debbugs.gnu.org
Subject: Building Guile with ‘-j1’?
Date: Wed, 20 Jan 2021 11:36:48 +0100
Message-ID: <db7ce8199737fbfffaf562c6ecf152cd30d057a4.camel@student.tugraz.at>

Hi Ludo,

IIUC this issue potentially affects all packages, that use Guile to
build more than two modules, no?

There could potentially be another workaround by synchronizing inside
guild, i.e. claiming a lock before reading and evaling any given source
file.  This would have the advantage of applying to all guile packages,
not just the ones that use guile-build-system, and it would also allow
non-Guile stuff, e.g. C extensions to be built in parallel.  WDYT?

Regards,
Leo

Re: Fwd: Building Guile with ‘-j1’?

[Mark H Weaver]

Leo Prikler <leo.prikler@student.tugraz.at> writes:

> There could potentially be another workaround by synchronizing inside
> guild, i.e. claiming a lock before reading and evaling any given source
> file.  This would have the advantage of applying to all guile packages,
> not just the ones that use guile-build-system, and it would also allow
> non-Guile stuff, e.g. C extensions to be built in parallel.  WDYT?

I don't think this would solve the problem, because it wouldn't ensure
that the Guile modules are compiled in a deterministic order, and
therefore the issue I raised in <https://bugs.gnu.org/20272#8> would
lead to nondeterministic results.

       Mark

Re: Fwd: Building Guile with ‘-j1’?

[Leo Prikler]

Am Mittwoch, den 20.01.2021, 16:08 -0500 schrieb Mark H Weaver:
> Leo Prikler <leo.prikler@student.tugraz.at> writes:
> 
> > There could potentially be another workaround by synchronizing
> > inside
> > guild, i.e. claiming a lock before reading and evaling any given
> > source
> > file.  This would have the advantage of applying to all guile
> > packages,
> > not just the ones that use guile-build-system, and it would also
> > allow
> > non-Guile stuff, e.g. C extensions to be built in parallel.  WDYT?
> 
> I don't think this would solve the problem, because it wouldn't
> ensure
> that the Guile modules are compiled in a deterministic order, and
> therefore the issue I raised in <https://bugs.gnu.org/20272#8> would
> lead to nondeterministic results.
> 
>        Mark
Because the OS might choose to schedule the tasks in a different order
than spawned, e.g. compilation tasks 1-4 start "simultaneously and get
reordered 1, 3, 2, 4?  Indeed, that would be a problem.  I don't
suppose file-lock based queues exist, do they?