From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Bavier <bavier@cray.com>
Subject: bug#28779: tests/workers.scm failure
Date: Tue, 10 Oct 2017 15:48:42 +0000
Message-ID: <BN6PR11MB1716104DFEB0F233C68756E5B7750@BN6PR11MB1716.namprd11.prod.outlook.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Return-path: <bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:50112)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1e1wnH-0007qh-2X
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:50:14 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1e1wnD-0006pR-85
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:50:07 -0400
Received: from debbugs.gnu.org ([208.118.235.43]:52124)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
	(Exim 4.71) (envelope-from <Debian-debbugs@debbugs.gnu.org>)
	id 1e1wnD-0006ot-3h
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:50:03 -0400
Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1e1wnC-0000lN-PS
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:50:02 -0400
Sender: "Debbugs-submit" <debbugs-submit-bounces@debbugs.gnu.org>
Resent-Message-ID: <handler.28779.B.15076505422841@debbugs.gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:49683)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <prvs=449b08b0a=bavier@cray.com>) id 1e1wm5-0006rW-53
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:48:54 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <prvs=449b08b0a=bavier@cray.com>) id 1e1wm2-0006GU-2Z
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:48:53 -0400
Received: from esa1.cray.iphmx.com ([68.232.142.33]:31738)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.71)
	(envelope-from <prvs=449b08b0a=bavier@cray.com>) id 1e1wm1-0006FJ-Ij
	for bug-guix@gnu.org; Tue, 10 Oct 2017 11:48:49 -0400
Content-Language: en-US
List-Id: Bug reports for GNU Guix <bug-guix.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/bug-guix>,
	<mailto:bug-guix-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/bug-guix/>
List-Post: <mailto:bug-guix@gnu.org>
List-Help: <mailto:bug-guix-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/bug-guix>,
	<mailto:bug-guix-request@gnu.org?subject=subscribe>
Errors-To: bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org
Sender: "bug-Guix" <bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org>
To: 28779@debbugs.gnu.org

Roughly 1 in 2 runs of tests/workers.scm fails on my system.  Output:

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D
   GNU Guix 0.13.0.3413-984e3-dirty: ./test-suite.log
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D

# TOTAL: 1
# PASS:  0
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0

.. contents:: :depth: 2

FAIL: tests/workers
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

test-name: enqueue
location: /home/users/bavier/src/guix/tests/workers.scm:26
source:
+ (test-equal
+   "enqueue"
+   4242
+   (let* ((pool (make-pool))
+          (result 0)
+          (#{1+!}# (let ((lock (make-mutex)))
+                     (lambda ()
+                       (with-mutex lock (set! result (+ result 1)))))))
+     (let loop ((i 4242))
+       (unless
+         (zero? i)
+         (pool-enqueue! pool #{1+!}#)
+         (loop (- i 1))))
+     (let poll ()
+       (unless
+         (pool-idle? pool)
+         (pk 'busy result)
+         (sleep 1)
+         (poll)))
+     result))
expected-value: 4242
actual-value: 4241
result: FAIL


To me the reason seems to be that the 'pool-idle? procedure indicates wheth=
er or not the task queue is empty, not whether all tasks have completed exe=
cution, so the poll loop exits before all 1+! updates are finished and the =
test fails. =20

Most failures show "actual-value: 4241", but I have also seen "actual-value=
: 4239" and "actual-value: 4240", which points to a race condition.

On this system '(current-processor-count) =3D> 128'

Eric Bavier, Scientific Libraries, Cray Inc.