Merge branch 'main' of github.com:bbelderbos/bobcodesit

Author: bbelderbos

index.md

@@ -336,6 +336,10 @@ This file gets generated by [this script](index.py).
 
 - [Pep 723 inline script metadata](notes/20251218125432.md)
 
+## Performance
+
+- [Reliable ci benchmarks with pytest-codspeed](notes/20260128144037.md)
+
 ## Plotext
 
 - [Make a terminal plot](notes/20240119105430.md)

notes/20260128144037.md

@@ -0,0 +1,19 @@
+# Reliable CI Benchmarks with pytest-codspeed
+
+Traditional CI benchmarks are noisy (10-30% variance) because they measure wall-clock time. CodSpeed uses CPU instruction simulation instead, giving you <1% variance—so you can actually trust the results.
+
+```python
+import pytest
+
+@pytest.mark.benchmark
+def test_my_algorithm(benchmark):
+    data = list(range(1000))
+    result = benchmark(my_algorithm, data)
+    assert result is not None
+```
+
+Run locally with `pytest` (wall-clock), in CI with `pytest --codspeed` (CPU simulation). The `--codspeed` flag only works in their CI environment—that's by design.
+
+Gotcha: push to `main` first to establish a baseline before creating PRs.
+
+#performance #ci #pytest