Files
babi/babi/perf.py
2020-09-01 09:54:56 -07:00

57 lines
1.6 KiB
Python

import contextlib
import cProfile
import time
from typing import Generator
from typing import List
from typing import Optional
from typing import Tuple
class Perf:
def __init__(self) -> None:
self._prof: Optional[cProfile.Profile] = None
self._records: List[Tuple[str, float]] = []
self._name: Optional[str] = None
self._time: Optional[float] = None
def start(self, name: str) -> None:
if self._prof:
assert self._name is None, self._name
self._name = name
self._time = time.monotonic()
self._prof.enable()
def end(self) -> None:
if self._prof:
assert self._name is not None
assert self._time is not None
self._prof.disable()
self._records.append((self._name, time.monotonic() - self._time))
self._name = self._time = None
def init_profiling(self) -> None:
self._prof = cProfile.Profile()
self.start('startup')
def save_profiles(self, filename: str) -> None:
assert self._prof is not None
self._prof.dump_stats(f'{filename}.pstats')
with open(filename, 'w', encoding='UTF-8') as f:
f.write('μs\tevent\n')
for name, duration in self._records:
f.write(f'{int(duration * 1000 * 1000)}\t{name}\n')
@contextlib.contextmanager
def perf_log(filename: Optional[str]) -> Generator[Perf, None, None]:
perf = Perf()
if filename is None:
yield perf
else:
perf.init_profiling()
try:
yield perf
finally:
perf.end()
perf.save_profiles(filename)