[New-bugs-announce] [issue44037] Broad performance regression from 3.10a7 to 3.10b1

Raymond Hettinger report at bugs.python.org
Tue May 4 14:19:14 EDT 2021

New submission from Raymond Hettinger <raymond.hettinger at gmail.com>:

Running Tools/scripts/var_access_benchmark.py on the production macOS builds on python.org shows a performance drop-off between alpha-7 and beta-1.

Apple Silicon
read local            4.1ns ->  4.5ns
read non_local        4.1ns ->  4.6ns
read global           4.2ns ->  4.9ns
read builtin          4.2ns ->  5.3ns
classvar from cls    10.1ns -> 12.6ns
classvar from inst    9.5      11.7
read instvar          9.2      11.3
instvar with slots    5.8       8.2
namedtuple           11.1      14.2

Since the effects are seen in almost every category, I suspect a build problem, a change to the eval loop, or a failure to inline some of the shared functions that used to be macros.

components: Build
keywords: 3.10regression
messages: 392934
nosy: rhettinger
priority: normal
severity: normal
status: open
title: Broad performance regression from 3.10a7 to 3.10b1
type: performance
versions: Python 3.10, Python 3.11

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