[Python-Dev] Python parser performance optimizations

[Artyom Skrobov]

Hello,

This is a monthly ping to get a review on http://bugs.python.org/issue26415 -- "Excessive peak memory consumption by the Python parser".
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.

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.

The absolute values, and the way they were produced, are all reported under the ticket.


From: Artyom Skrobov
Sent: 26 May 2016 11:19
To: 'python-dev at python.org'
Subject: Python parser performance optimizations

Hello,

Back in March, I've posted a patch at http://bugs.python.org/issue26526 -- "In parsermodule.c, replace over 2KLOC of hand-crafted validation code, with a DFA".

The motivation for this patch was to enable a memory footprint optimization, discussed at http://bugs.python.org/issue26415
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.
The run time stays unaffected by this optimization.

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 python-dev at python.org<mailto:python-dev at python.org> asking for someone to review your patch."

So, here I am.
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