<div dir="ltr">Yes, we do see performance benefits for this change on some google internal benchmarks.<div><br></div><div>Dehao</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, May 19, 2017 at 6:18 AM, 陳韋任 <span dir="ltr"><<a href="mailto:chenwj.cs97g@g2.nctu.edu.tw" target="_blank">chenwj.cs97g@g2.nctu.edu.tw</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Besides speccpu, any other real-world applications benefit from this option?</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Regards,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">chenwj</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">2017-05-19 6:30 GMT+08:00 Dehao Chen via llvm-dev <span dir="ltr"><<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>></span>:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">Hi,<div><br></div><div>I'm proposing to make vectorizer-maximize-bandw<wbr>idth on by default for loop vectorizer because it should generally help performance.</div><div><br></div><div>I've tested the performance impact on Intel sandybridge machine with speccpu benchmarks:</div><div><br></div><div><div> Benchmark Base:Reference (1) </div><div>------------------------------<wbr>-------------------------</div><div>spec/2006/fp/C++/444.namd 26.84 -0.31%</div><div>spec/2006/fp/C++/447.dealII 46.19 +0.89%</div><div>spec/2006/fp/C++/450.soplex 42.92 -0.44%</div><div>spec/2006/fp/C++/453.povray 38.57 -2.25%</div><div>spec/2006/fp/C/433.milc 24.54 -0.76%</div><div>spec/2006/fp/C/470.lbm 41.08 +0.26%</div><div>spec/2006/fp/C/482.sphinx3 47.58 -0.99%</div><div>spec/2006/int/C++/471.omnetpp 22.06 +1.87%</div><div>spec/2006/int/C++/473.astar 22.65 -0.12%</div><div>spec/2006/int/C++/483.xalancbm<wbr>k 33.69 +4.97%</div><div>spec/2006/int/C/400.perlbench 33.43 +1.70%</div><div>spec/2006/int/C/401.bzip2 23.02 -0.19%</div><div>spec/2006/int/C/403.gcc 32.57 -0.43%</div><div>spec/2006/int/C/429.mcf 40.35 +0.27%</div><div>spec/2006/int/C/445.gobmk 26.96 +0.06%</div><div>spec/2006/int/C/456.hmmer 24.4 +0.19%</div><div>spec/2006/int/C/458.sjeng 27.91 -0.08%</div><div>spec/2006/int/C/462.libquantum 57.47 -0.20%</div><div>spec/2006/int/C/464.h264ref 46.52 +1.35%</div><div><br></div><div>geometric mean +0.29%</div><div><br></div><div> Scores are benchmark specific.</div></div><div><br></div><div>We do have regression on 453.povray, but it's due to secondary effects as all hot functions are the same. I've also tested the code size impact, it does not change for tested speccpu benchmarks.</div><div><br></div><div>I've prepared <a href="https://reviews.llvm.org/D33341" rel="noreferrer" style="font-size:12.8px" target="_blank">https://reviews.llvm.<wbr>org/D33341</a> to do this.</div><div><br></div><div>I really appreciate if the community can help test the performance impact of this change on other architectures so that we can decide if this should go target-dependent.</div><div><br></div><div>Any comments/concerns?</div><div><br></div><div>Thanks,</div><div>Dehao</div></div>
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<br></blockquote></div><span class="HOEnZb"><font color="#888888"><br><br clear="all"><div><br></div>-- <br><div class="m_-1496353057319846569gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>Wei-Ren Chen (陳韋任)<br>Homepage: <a href="https://people.cs.nctu.edu.tw/~chenwj" target="_blank">https://people.cs.nctu.edu.tw/<wbr>~chenwj</a></div></div></div>
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