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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Thanks. Could you open a Trac ticket, and explain carefully how to reproduce your results?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Surely 8.4 should be faster than 7.10!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Simon<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><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"> ghc-devs [mailto:ghc-devs-bounces@haskell.org]
<b>On Behalf Of </b>Harendra Kumar<br>
<b>Sent:</b> 01 August 2017 10:46<br>
<b>To:</b> ghc-devs@haskell.org<br>
<b>Subject:</b> GHC 8.2 generated code faster than 8.0 but slower than 7.10<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:6.0pt;margin-right:0cm;margin-bottom:6.0pt;margin-left:0cm">
Unicode normalization library (<a href="https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fharendra-kumar%2Funicode-transforms&data=04%7C01%7Csimonpj%40microsoft.com%7Cea675f49b17b45582c5708d4d8c22226%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636371775684809111%7CUnknown%7CVW5rbm93bnx7IlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiT3RoZXIifQ%3D%3D%7C-1&sdata=4YlXVWqT4DKYHpgUcq9YF%2BiX2xH%2BLAHgI4GFCGt6zwg%3D&reserved=0">https://github.com/harendra-kumar/unicode-transforms</a>)
shows around 10% improvement with GHC 8.2.1 when compared to GHC 8.0.1, across most benchmarks. However, it is still somewhat slower when compared to GHC 7.10.3. Here are some results:<o:p></o:p></p>
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<o:p> </o:p></p>
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GHC 7.10.3:<br>
<br>
benchmarking unicode-transforms-text/NFD/English<br>
time 4.823 ms (4.765 ms .. 4.902 ms)<br>
<br>
benchmarking unicode-transforms-text/NFD/Devanagari<br>
time 16.46 ms (16.24 ms .. 16.78 ms)<br>
<br>
<br>
GHC 8.0.1<br>
<br>
<br>
benchmarking unicode-transforms-text/NFD/English<br>
time 6.330 ms (6.232 ms .. 6.439 ms)<br>
<br>
benchmarking unicode-transforms-text/NFD/Devanagari<br>
time 18.02 ms (17.77 ms .. 18.22 ms)<br>
<br>
GHC 8.2.1<br>
<br>
<br>
benchmarking unicode-transforms-text/NFD/English<br>
time 5.659 ms (5.594 ms .. 5.740 ms)<br>
<br>
benchmarking unicode-transforms-text/NFD/Devanagari<br>
time 16.48 ms (16.30 ms .. 16.69 ms)<o:p></o:p></p>
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<o:p> </o:p></p>
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This library has been optimized with an objective to match or better (in some cases it is better) the performance of the equivalent ICU C++ library (compare only decompose normalization). Some of the last hurdles to match the best case of C++ were in the code
generated by GHC. Also, for GHC 7.10 LLVM generated code is significantly faster than GHC native, I have not yet tested LLVM backend with 8.2.1 so not sure if that too has improved correspondingly.<o:p></o:p></p>
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<o:p> </o:p></p>
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I just wanted to share these results with the GHC devs. Thanks for all the good work. Also wondering which specific changes might have caused this improvement.<o:p></o:p></p>
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<o:p> </o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:6.0pt;margin-right:0cm;margin-bottom:6.0pt;margin-left:0cm">
Thanks,<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:6.0pt;margin-right:0cm;margin-bottom:6.0pt;margin-left:0cm">
Harendra<o:p></o:p></p>
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