From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17532 invoked by alias); 21 Dec 2012 04:06:51 -0000 Received: (qmail 17524 invoked by uid 22791); 21 Dec 2012 04:06:50 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,RCVD_VIA_APNIC,T_MANY_HDRS_LCASE X-Spam-Check-By: sourceware.org Received: from comm.purplecow.org (HELO comm.purplecow.org) (210.87.62.131) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 21 Dec 2012 04:06:42 +0000 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-disposition: inline Content-type: text/plain; charset=us-ascii Received: from comm.purplecow.org ([127.0.0.1]) by comm.purplecow.org (Sun Java(tm) System Messaging Server 6.3-6.03 (built Mar 14 2008; 32bit)) with ESMTP id <0MFD00E0G4R46200@comm.purplecow.org> for gcc-help@gcc.gnu.org; Fri, 21 Dec 2012 15:06:40 +1100 (EST) Received: from comm.purplecow.org ([127.0.0.1] helo=comm.purplecow.org) with IPv4:25 by ASSP.nospam; Fri, 21 Dec 2012 15:06:40 +1100 Received: from [66.103.52.207] by comm.purplecow.org (mshttpd); Thu, 20 Dec 2012 23:06:40 -0500 From: Dennis Clarke To: gcc-help@gcc.gnu.org Cc: Jonathan Wakely , Ian Lance Taylor Message-id: Date: Fri, 21 Dec 2012 04:06:00 -0000 Subject: parallel testsuite results differ from a single task approach X-IsSubscribed: yes Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-help-owner@gcc.gnu.org X-SW-Source: 2012-12/txt/msg00114.txt.bz2 I gad received some good advice to try using gmake -j X -k check for some X > 1 when running a testsuite in order to speed the process up. So I decided to test that theory with an eye on the results. I was surprised to see that the results when running "gmake -j 8 -k check" differ from a simple "gmake -k check" in the area of go and libmudflap : 1 ) parallel testsuite : http://gcc.gnu.org/ml/gcc-testresults/2012-12/msg01903.html 2 ) single process testsuite : http://gcc.gnu.org/ml/gcc-testresults/2012-12/msg01935.html In parallel we see this for "go" : === go tests === Running target unix FAIL: go.test/test/stack.go execution, -O2 -g === go Summary === # of expected passes 3293 # of unexpected failures 1 # of expected failures 4 # of untested testcases 4 /home/dclarke/pgm/build/gcc-4.7.2_2.6.32-279.14.1.el6.x86_64.004/gcc/testsuite/go/../../gccgo version 4.7.2 (Blastwave.org Inc. time_rfc-3339=2012-12-20 11:23:25+00:00) While the single process apporach reports : === go Summary === # of expected passes 3294 # of expected failures 4 # of untested testcases 4 /home/dclarke/pgm/build/gcc-4.7.2_2.6.32-279.14.1.el6.x86_64.004/gcc/testsuite/go/../../gccgo version 4.7.2 (Blastwave.org Inc. time_rfc-3339=2012-12-20 11:23:25+00:00) Perhaps the go test "go.test/test/stack.go" is somehow sensitive to running on a busy machine? I am only guessing. The "libmudflap tests" results are wildly different. So at first glance it appears that the testsuite will in fact product different results if one chooses to use "gmake -j X" for X>1 but I am not sure why. Felt is was worth pointing out as maybe no one else has done the comparison. Dennis