From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark H Weaver <mhw@netris.org>
Subject: bug#28211: Grafting fails for latest Go release candidate
Date: Thu, 24 Aug 2017 00:56:30 -0400
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In-Reply-To: <87lgm9j3q9.fsf@gnu.org> ("Ludovic
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To: Ludovic =?UTF-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Cc: Andy Wingo <wingo@igalia.com>, guix-devel@gnu.org, 28211@debbugs.gnu.org

ludo@gnu.org (Ludovic Court=C3=A8s) writes:

> Marius Bakke <mbakke@fastmail.com> skribis:
>
>> Most likely just lucky, new grafting failure today.
>>
>> I've noticed they are more likely to occur when the host system is busy.
>> Grafting a large package such as 'texlive' is almost guaranteed to fail
>> on a fully-utilized machine.
>>
>> Maybe we should switch back to 2.0 for the time being?
>
> Yes, done: <https://bugs.gnu.org/28211>.
>
> I took a look: the code in (guix build graft) is multi-threaded but
> there=E2=80=99s no shared state among threads (except for the current
> output/error ports,

In Guile, port operations do not include built-in thread
synchronization, so it's not safe for multiple threads to write to the
current output/error ports concurrently.  Those writes should be
protected by a mutex.

However, we had agreed that in 2.2, the port operations should be
implemented in such a way that the worst that could happen on typical
hardware in practice was for the output to be garbled.  I didn't review
the new 2.2 ports code, so I'm not sure whether this was accomplished.

      Mark