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<p class="MsoNormal"><span style="color:#1F497D">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This is a monthly ping to get a review on
<a href="http://bugs.python.org/issue26415">http://bugs.python.org/issue26415</a> -- “Excessive peak memory consumption by the Python parser”.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The first patch of the series (an NFC refactoring) was successfully committed earlier in June, so the next step is to get the second patch, “the payload”, reviewed and committed.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">To address the concerns raised by the commenters back in May: the patch doesn’t lead to negative memory consumption, of course. The base for calculating percentages is the smaller number of the two; this is the
same style of reporting that perf.py uses. In other words, “200% less memory usage” is a threefold shrink.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The absolute values, and the way they were produced, are all reported under the ticket.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";mso-fareast-language:EN-GB">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";mso-fareast-language:EN-GB"> Artyom
Skrobov <br>
<b>Sent:</b> 26 May 2016 11:19<br>
<b>To:</b> 'python-dev@python.org'<br>
<b>Subject:</b> Python parser performance optimizations<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Back in March, I’ve posted a patch at <a href="http://bugs.python.org/issue26526">
http://bugs.python.org/issue26526</a> -- “In parsermodule.c, replace over 2KLOC of hand-crafted validation code, with a DFA”.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The motivation for this patch was to enable a memory footprint optimization, discussed at
<a href="http://bugs.python.org/issue26415">http://bugs.python.org/issue26415</a><o:p></o:p></p>
<p class="MsoNormal">My proposed optimization reduces the memory footprint by up to 30% on the standard benchmarks, and by 200% on a degenerate case which sparked the discussion.<o:p></o:p></p>
<p class="MsoNormal">The run time stays unaffected by this optimization.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Python Developer’s Guide says: “If you don’t get a response within a few days after pinging the issue, then you can try emailing
<a href="mailto:python-dev@python.org">python-dev@python.org</a> asking for someone to review your patch.”<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So, here I am.<o:p></o:p></p>
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