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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Actually the performance problem is separate from<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US">supported version or linker errors or compiler used.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US">So we apparently need to investigate the problem
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US">in the OpenMP runtime. We will work on this.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Verdana",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Andrey<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Openmp-dev [mailto:openmp-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Bataev, Alexey via Openmp-dev<br>
<b>Sent:</b> Thursday, August 20, 2015 6:08 AM<br>
<b>To:</b> Finkel, Hal J.<br>
<b>Cc:</b> openmp-dev@lists.llvm.org<br>
<b>Subject:</b> Re: [Openmp-dev] Performance slowdown<o:p></o:p></span></p>
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<p class="MsoNormal">Yes, but still this version is not optimal. Clang trunk will produce a little bit faster code.<br>
<br>
<o:p></o:p></p>
<pre>Best regards,<o:p></o:p></pre>
<pre>Alexey Bataev<o:p></o:p></pre>
<pre>=============<o:p></o:p></pre>
<pre>Software Engineer<o:p></o:p></pre>
<pre>Intel Compiler Team<o:p></o:p></pre>
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<p class="MsoNormal">19.08.2015 23:39, Finkel, Hal J. via Openmp-dev пишет:<o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">Sent from my Verizon Wireless 4G LTE DROID</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">On Aug 19, 2015 1:36 PM, César via Openmp-dev <<a href="mailto:openmp-dev@lists.llvm.org">openmp-dev@lists.llvm.org</a>> wrote:</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">> On Wed, Aug 19, 2015 at 3:07 PM, Jack Howarth <<a href="mailto:howarth.mailing.lists@gmail.com">howarth.mailing.lists@gmail.com</a>> wrote:</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> On Tue, Aug 18, 2015 at 2:14 PM, César via Openmp-dev</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> <<a href="mailto:openmp-dev@lists.llvm.org">openmp-dev@lists.llvm.org</a>> wrote:</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > Hello,</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > I don't know if this is the correct list to talk about this - I did not find</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > a better place..</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > I am doing performance experiments with a few OpenMP implementations (IOMP,</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > GOMP and our private impl.) and I am seeing a severe slowdown when I use</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > IOMP (GOMP and others are performing well).</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > The benchmarks I am using are these ones:</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > <a href="http://kastors.gforge.inria.fr/#!index.md">
http://kastors.gforge.inria.fr/#!index.md</a></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> That web page claims the benchmarks use parts of the OpenMP 4.0 specification.</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> "The KaStORS benchmark suite has been designed to evaluate the implementation of</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> the OpenMP dependent task paradigm, introduced as part of the OpenMP 4.0</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> specification."</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> Currently openmp is only complete for the OpenMP 3.2 specification</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">> I am able to compile a few benchmarks that use task dependence annotations (from OMP 4.0) but for those that specify the range of the memory dependence I get syntax error. So, should I assume that this part
is not implemented, right? Is there a list for the OMP 4.0 items that are currently supported?</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">> BTW, the Clang version from Github was able to parse these annotations, was it dropped from the current newer version?</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">It is not there yet. You'll need to use the code from the github clang_trunk (and llvm_trunk, etc.) repositories to get both recent Clang/LLVM and all of the OpenMP features.</span></i><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">-Hal</span></i><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">> </span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > Really, the slowdown is huge. For one of the programs (plasma/dpotrf_taskdep</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > -n 8192 -b 64 -i 1 -c) the serial version executes in ~28s and the parallel</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > one executes in ~110s. I did some profiling and found that most of the time</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > is being spent on synchronization barriers and dependence tracking (see</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > attached image). Before digging deeper I would like to hear back from you if</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > I am doing something wrong here:</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > - I tested with the last version of the repository:</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > <a href="http://llvm.org/svn/llvm-project/openmp/trunk">
http://llvm.org/svn/llvm-project/openmp/trunk</a></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > - I am using Ubuntu 14.10.</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > - I have tested on more than one machine, the results above are from a Intel</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > i7-3770</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > - The runtime itself is compiled using: make compiler=gcc os_omp=linux</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > arch=32e</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > - The version of GCC that I am using is: 4.9.1</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > - The version of Clang that I am using to compile the benchmarks: 3.5.0</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > César.</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > _______________________________________________</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > Openmp-dev mailing list</span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > <a href="mailto:Openmp-dev@lists.llvm.org">
Openmp-dev@lists.llvm.org</a></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> > <a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev">
http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev</a></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">>> ></span></i><o:p></o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">></span></i><o:p> </o:p></p>
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<p class="MsoNormal"><i><span style="color:#333333">Sent from my Verizon Wireless 4G LTE DROID</span></i><o:p></o:p></p>
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<p class="MsoNormal"><br>
<br>
<br>
<o:p></o:p></p>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>Openmp-dev mailing list<o:p></o:p></pre>
<pre><a href="mailto:Openmp-dev@lists.llvm.org">Openmp-dev@lists.llvm.org</a><o:p></o:p></pre>
<pre><a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev">http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev</a><o:p></o:p></pre>
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