X-Recipient: archive-cygwin AT delorie DOT com X-SWARE-Spam-Status: No, hits=-1.6 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Message-ID: <4F29F118.50206@aol.com> Date: Wed, 01 Feb 2012 21:12:40 -0500 From: Tim Prince Reply-To: tprince AT computer DOT org User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 MIME-Version: 1.0 To: cygwin AT cygwin DOT com Subject: Re: MinGW gfortran and OpenMP issues... References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:334845888:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d29444f29f118131d X-AOL-IP: 69.133.204.177 Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com On 2/1/2012 7:03 PM, Nick Chilton wrote: > Hi, > > I'm still having problems with OpenMP and the x86_64 MinGW compilers - > code which can run fine on Linux with any number of threads (mapped to > different cores) still will only use one core on an i5 quad core > windows box. Is this a windows limitation or a compiler one? > > Compile with: > > x86_64-w64-mingw32-gfortran.exe -o a.exe -mno-cygwin -static -O3 > -fopenmp -cpp -Domp $(SOURCES) -L/home/Nick/lib/ -llapack -lblas > > According to my understanding, mingw compiler versions aren't supported on this list, notwithstanding that cygwin install is probably the best way to get them. However, that compiler gives me good OpenMP performance on 6 of 10 test cases, running on an early core I7 with HyperThread disabled, Win7SP1. GOMP_AFFINITY setting as well as avoiding Hyper-Threading are likely more important on Windows than linux. Win7SP1 is particularly important when using Hyper-Threading. -- Tim Prince -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple