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"""Benchmark some basic import use-cases.
The assumption is made that this benchmark is run in a fresh interpreter and
thus has no external changes made to import-related attributes in sys.
"""
from . import util
from .source import util as source_util
import decimal
import imp
import importlib
import os
import py_compile
import sys
import timeit
def bench(name, cleanup=lambda: None, *, seconds=1, repeat=3):
"""Bench the given statement as many times as necessary until total
executions take one second."""
stmt = "__import__({!r})".format(name)
timer = timeit.Timer(stmt)
for x in range(repeat):
total_time = 0
count = 0
while total_time < seconds:
try:
total_time += timer.timeit(1)
finally:
cleanup()
count += 1
else:
# One execution too far
if total_time > seconds:
count -= 1
yield count // seconds
def from_cache(seconds, repeat):
"""sys.modules"""
name = '<benchmark import>'
module = imp.new_module(name)
module.__file__ = '<test>'
module.__package__ = ''
with util.uncache(name):
sys.modules[name] = module
for result in bench(name, repeat=repeat, seconds=seconds):
yield result
def builtin_mod(seconds, repeat):
"""Built-in module"""
name = 'errno'
if name in sys.modules:
del sys.modules[name]
# Relying on built-in importer being implicit.
for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
seconds=seconds):
yield result
def source_wo_bytecode(seconds, repeat):
"""Source w/o bytecode: simple"""
sys.dont_write_bytecode = True
try:
name = '__importlib_test_benchmark__'
# Clears out sys.modules and puts an entry at the front of sys.path.
with source_util.create_modules(name) as mapping:
assert not os.path.exists(imp.cache_from_source(mapping[name]))
for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
seconds=seconds):
yield result
finally:
sys.dont_write_bytecode = False
def decimal_wo_bytecode(seconds, repeat):
"""Source w/o bytecode: decimal"""
name = 'decimal'
decimal_bytecode = imp.cache_from_source(decimal.__file__)
if os.path.exists(decimal_bytecode):
os.unlink(decimal_bytecode)
sys.dont_write_bytecode = True
try:
for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
seconds=seconds):
yield result
finally:
sys.dont_write_bytecode = False
def source_writing_bytecode(seconds, repeat):
"""Source writing bytecode: simple"""
assert not sys.dont_write_bytecode
name = '__importlib_test_benchmark__'
with source_util.create_modules(name) as mapping:
def cleanup():
sys.modules.pop(name)
os.unlink(imp.cache_from_source(mapping[name]))
for result in bench(name, cleanup, repeat=repeat, seconds=seconds):
assert not os.path.exists(imp.cache_from_source(mapping[name]))
yield result
def decimal_writing_bytecode(seconds, repeat):
"""Source writing bytecode: decimal"""
assert not sys.dont_write_bytecode
name = 'decimal'
def cleanup():
sys.modules.pop(name)
os.unlink(imp.cache_from_source(decimal.__file__))
for result in bench(name, cleanup, repeat=repeat, seconds=seconds):
yield result
def source_using_bytecode(seconds, repeat):
"""Bytecode w/ source: simple"""
name = '__importlib_test_benchmark__'
with source_util.create_modules(name) as mapping:
py_compile.compile(mapping[name])
assert os.path.exists(imp.cache_from_source(mapping[name]))
for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
seconds=seconds):
yield result
def decimal_using_bytecode(seconds, repeat):
"""Bytecode w/ source: decimal"""
name = 'decimal'
py_compile.compile(decimal.__file__)
for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
seconds=seconds):
yield result
def main(import_):
__builtins__.__import__ = import_
benchmarks = (from_cache, builtin_mod,
source_using_bytecode, source_wo_bytecode,
source_writing_bytecode,
decimal_using_bytecode, decimal_writing_bytecode,
decimal_wo_bytecode,)
seconds = 1
seconds_plural = 's' if seconds > 1 else ''
repeat = 3
header = "Measuring imports/second over {} second{}, best out of {}\n"
print(header.format(seconds, seconds_plural, repeat))
for benchmark in benchmarks:
print(benchmark.__doc__, "[", end=' ')
sys.stdout.flush()
results = []
for result in benchmark(seconds=seconds, repeat=repeat):
results.append(result)
print(result, end=' ')
sys.stdout.flush()
assert not sys.dont_write_bytecode
print("]", "best is", format(max(results), ',d'))
if __name__ == '__main__':
import optparse
parser = optparse.OptionParser()
parser.add_option('-b', '--builtin', dest='builtin', action='store_true',
default=False, help="use the built-in __import__")
options, args = parser.parse_args()
if args:
raise RuntimeError("unrecognized args: {}".format(args))
import_ = __import__
if not options.builtin:
import_ = importlib.__import__
main(import_)
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