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# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
# Run like this:
# .tox/py36/bin/python perf/perf_measure.py
from collections import namedtuple
import os
import statistics
import sys
import tempfile
import time
from unittest_mixins.mixins import make_file
import coverage
from coverage.backward import import_local_file
from tests.helpers import SuperModuleCleaner
class StressResult(namedtuple('StressResult', ['files', 'calls', 'lines', 'baseline', 'covered'])):
@property
def overhead(self):
return self.covered - self.baseline
TEST_FILE = """\
def parent(call_count, line_count):
for _ in range(call_count):
child(line_count)
def child(line_count):
for i in range(line_count):
x = 1
"""
def mk_main(file_count, call_count, line_count):
lines = []
lines.extend(
"import test{}".format(idx) for idx in range(file_count)
)
lines.extend(
"test{}.parent({}, {})".format(idx, call_count, line_count) for idx in range(file_count)
)
return "\n".join(lines)
class StressTest(object):
def __init__(self):
self.module_cleaner = SuperModuleCleaner()
def _run_scenario(self, file_count, call_count, line_count):
self.module_cleaner.clean_local_file_imports()
for idx in range(file_count):
make_file('test{}.py'.format(idx), TEST_FILE)
make_file('testmain.py', mk_main(file_count, call_count, line_count))
# Run it once just to get the disk caches loaded up.
import_local_file("testmain")
self.module_cleaner.clean_local_file_imports()
# Run it to get the baseline time.
start = time.perf_counter()
import_local_file("testmain")
baseline = time.perf_counter() - start
self.module_cleaner.clean_local_file_imports()
# Run it to get the covered time.
start = time.perf_counter()
cov = coverage.Coverage()
cov.start()
try: # pragma: nested
# Import the Python file, executing it.
import_local_file("testmain")
finally: # pragma: nested
# Stop coverage.py.
covered = time.perf_counter() - start
stats = cov._collector.tracers[0].get_stats()
if stats:
stats = stats.copy()
cov.stop()
return baseline, covered, stats
def _compute_overhead(self, file_count, call_count, line_count):
baseline, covered, stats = self._run_scenario(file_count, call_count, line_count)
#print("baseline = {:.2f}, covered = {:.2f}".format(baseline, covered))
# Empirically determined to produce the same numbers as the collected
# stats from get_stats(), with Python 3.6.
actual_file_count = 17 + file_count
actual_call_count = file_count * call_count + 156 * file_count + 85
actual_line_count = (
2 * file_count * call_count * line_count +
3 * file_count * call_count +
769 * file_count +
345
)
if stats is not None:
assert actual_file_count == stats['files']
assert actual_call_count == stats['calls']
assert actual_line_count == stats['lines']
print("File counts", file_count, actual_file_count, stats['files'])
print("Call counts", call_count, actual_call_count, stats['calls'])
print("Line counts", line_count, actual_line_count, stats['lines'])
print()
return StressResult(
actual_file_count,
actual_call_count,
actual_line_count,
baseline,
covered,
)
fixed = 200
numlo = 100
numhi = 100
step = 50
runs = 5
def count_operations(self):
def operations(thing):
for _ in range(self.runs):
for n in range(self.numlo, self.numhi+1, self.step):
kwargs = {
"file_count": self.fixed,
"call_count": self.fixed,
"line_count": self.fixed,
}
kwargs[thing+"_count"] = n
yield kwargs['file_count'] * kwargs['call_count'] * kwargs['line_count']
ops = sum(sum(operations(thing)) for thing in ["file", "call", "line"])
print("{0:.1f}M operations".format(ops/1e6))
def check_coefficients(self):
# For checking the calculation of actual stats:
for f in range(1, 6):
for c in range(1, 6):
for l in range(1, 6):
_, _, stats = self._run_scenario(f, c, l)
print("{0},{1},{2},{3[files]},{3[calls]},{3[lines]}".format(f, c, l, stats))
def stress_test(self):
# For checking the overhead for each component:
def time_thing(thing):
per_thing = []
pct_thing = []
for _ in range(self.runs):
for n in range(self.numlo, self.numhi+1, self.step):
kwargs = {
"file_count": self.fixed,
"call_count": self.fixed,
"line_count": self.fixed,
}
kwargs[thing+"_count"] = n
res = self._compute_overhead(**kwargs)
per_thing.append(res.overhead / getattr(res, "{}s".format(thing)))
pct_thing.append(res.covered / res.baseline * 100)
out = "Per {}: ".format(thing)
out += "mean = {:9.3f}us, stddev = {:8.3f}us, ".format(
statistics.mean(per_thing)*1e6, statistics.stdev(per_thing)*1e6
)
out += "min = {:9.3f}us, ".format(min(per_thing)*1e6)
out += "pct = {:6.1f}%, stddev = {:6.1f}%".format(
statistics.mean(pct_thing), statistics.stdev(pct_thing)
)
print(out)
time_thing("file")
time_thing("call")
time_thing("line")
if __name__ == '__main__':
with tempfile.TemporaryDirectory(prefix="coverage_stress_") as tempdir:
print("Working in {}".format(tempdir))
os.chdir(tempdir)
sys.path.insert(0, ".")
StressTest().stress_test()
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