GeezerVison

import pyperf
import xml.etree.ElementTree as ET


def make_doc(n_elements, n_attrs):
    attrs = " ".join(f'a{i}="v{i}"' for i in range(n_attrs))
    body = "".join(f"<item {attrs}/>" for _ in range(n_elements))
    return f"<root>{body}</root>"


DOCS = {
    "many-attrs-per-elem": make_doc(n_elements=2000, n_attrs=16),
    "few-attrs-many-elems": make_doc(n_elements=20000, n_attrs=2),
    "wide-attrs": make_doc(n_elements=200, n_attrs=64),
}


if __name__ == "__main__":
    runner = pyperf.Runner()
    for name, xml in DOCS.items():
        runner.bench_func(f"ET.fromstring {name}", ET.fromstring, xml)

+------------------------------------+---------+-----------------------+
| Benchmark                          | base    | opt                   |
+====================================+=========+=======================+
| ET.fromstring many-attrs-per-elem  | 9.07 ms | 8.51 ms: 1.07x faster |
+------------------------------------+---------+-----------------------+
| ET.fromstring few-attrs-many-elems | 20.3 ms | 19.6 ms: 1.03x faster |
+------------------------------------+---------+-----------------------+
| ET.fromstring wide-attrs           | 3.29 ms | 3.08 ms: 1.07x faster |
+------------------------------------+---------+-----------------------+
| Geometric mean                     | (ref)   | 1.06x faster          |
+------------------------------------+---------+-----------------------+