Adrian Wielgosik added the comment:
Added a PR with a fast path that triggers when compared arrays store values of
the same type. In this fast path, no Python objects are created. For big arrays
the runtime reduction can reach 50-100x.
It's possible to optimize the comparison loop a bit more - for example
array('B') comparison could use memcmp and become extra 10x faster, and other
types could receive similar treatment - but I wanted to keep the code
relatively simple.
Code duplication with macros is a bit ugly, but that's the best I could come up
with so far.
Benchmark results:
Test Before After % of old time
Equal, same stored type (new fast path)
array('i', range(0)) 20.4ns 22.07ns 108.15%
array('i', range(1)) 33.39ns 22.32ns 66.86%
array('i', range(10)) 152.0ns 31.21ns 20.54%
array('i', range(10000)) 447.7us 6.571us 1.47%
array('i', range(100000)) 4.626ms 67.24us 1.45%
array('i', [1<<30]*100000)) 5.234ms 65.8us 1.26%
array('B', range(10)) 151.8ns 28.53ns 18.79%
array('B', range(250)) 3.14us 194.5ns 6.19%
array('B', [1,2,3]*1000) 37.76us 2.088us 5.53%
array('d', range(10)) 311.9ns 31.22ns 10.01%
array('d', range(100000)) 2.889ms 99.3us 3.44%
Equal, different types (slow path)
array('X', range(0)) 20.37ns 19.45ns 95.48%
array('X', range(1)) 34.87ns 34.42ns 98.72%
array('X', range(10)) 169.1ns 169.0ns 99.97%
array('X', range(10000)) 462.2us 444.8us 96.23%
array('X', range(100000)) 4.752ms 4.571ms 96.20%
Not equal: first element (X) different
array('i', [X] + [1,2,3]*10000) 42.77ns 21.84ns 51.06%
Not equal: last element (X) different
array('i', [1,2,3]*10000 + [X]) 375.4us 19.8us 5.27%
----------
nosy: +Adrian Wielgosik
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