Noticed weird slowness when summarizing test results by suite vs case.
Turns out the way we accumulate results by overloading Python's __add__
quickly leads to O(n^2) behavior as we repeatedly concatenate
increasingly large lists.
Instead of doing anything sane, I've added a second, immutable length to
each list such that we can opportunistically reuse/mutate/append lists
in __add__. The end result should be O(n) most of the time.
Observe:
lines bytes
test.csv: 537749 64551874 62MiB
./scripts/summary.py test.csv -ftest_time -S
before after
-bcase: 0m51.772s 0m9.302s (-82.0%)
-bsuite: 10m29.067s 0m9.357s (-98.5%)
Christopher Haster
7a7da9680a