1 files changed, 252 insertions, 0 deletions
diff --git a/Tools/importbench/importbench.py b/Tools/importbench/importbench.py
new file mode 100644
index 0000000000..714c0e427f
--- /dev/null
+++ b/Tools/importbench/importbench.py
@@ -0,0 +1,252 @@
+"""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 test.test_importlib import util
+from test.test_importlib.source import util as source_util
+import decimal
+import imp
+import importlib
+import importlib.machinery
+import json
+import os
+import py_compile
+import sys
+import tabnanny
+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: small"""
+    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]))
+            sys.meta_path.append(importlib.machinery.PathFinder)
+            loader = (importlib.machinery.SourceFileLoader,
+                      importlib.machinery.SOURCE_SUFFIXES, True)
+            sys.path_hooks.append(importlib.machinery.FileFinder.path_hook(loader))
+            for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
+                                seconds=seconds):
+                yield result
+    finally:
+        sys.dont_write_bytecode = False
+
+
+def _wo_bytecode(module):
+    name = module.__name__
+    def benchmark_wo_bytecode(seconds, repeat):
+        """Source w/o bytecode: {}"""
+        bytecode_path = imp.cache_from_source(module.__file__)
+        if os.path.exists(bytecode_path):
+            os.unlink(bytecode_path)
+        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
+
+    benchmark_wo_bytecode.__doc__ = benchmark_wo_bytecode.__doc__.format(name)
+    return benchmark_wo_bytecode
+
+tabnanny_wo_bytecode = _wo_bytecode(tabnanny)
+decimal_wo_bytecode = _wo_bytecode(decimal)
+
+
+def source_writing_bytecode(seconds, repeat):
+    """Source writing bytecode: small"""
+    assert not sys.dont_write_bytecode
+    name = '__importlib_test_benchmark__'
+    with source_util.create_modules(name) as mapping:
+        sys.meta_path.append(importlib.machinery.PathFinder)
+        loader = (importlib.machinery.SourceFileLoader,
+                  importlib.machinery.SOURCE_SUFFIXES, True)
+        sys.path_hooks.append(importlib.machinery.FileFinder.path_hook(loader))
+        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 _writing_bytecode(module):
+    name = module.__name__
+    def writing_bytecode_benchmark(seconds, repeat):
+        """Source writing bytecode: {}"""
+        assert not sys.dont_write_bytecode
+        def cleanup():
+            sys.modules.pop(name)
+            os.unlink(imp.cache_from_source(module.__file__))
+        for result in bench(name, cleanup, repeat=repeat, seconds=seconds):
+            yield result
+
+    writing_bytecode_benchmark.__doc__ = (
+                                writing_bytecode_benchmark.__doc__.format(name))
+    return writing_bytecode_benchmark
+
+tabnanny_writing_bytecode = _writing_bytecode(tabnanny)
+decimal_writing_bytecode = _writing_bytecode(decimal)
+
+
+def source_using_bytecode(seconds, repeat):
+    """Source w/ bytecode: small"""
+    name = '__importlib_test_benchmark__'
+    with source_util.create_modules(name) as mapping:
+        sys.meta_path.append(importlib.machinery.PathFinder)
+        loader = (importlib.machinery.SourceFileLoader,
+                importlib.machinery.SOURCE_SUFFIXES, True)
+        sys.path_hooks.append(importlib.machinery.FileFinder.path_hook(loader))
+        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 _using_bytecode(module):
+    name = module.__name__
+    def using_bytecode_benchmark(seconds, repeat):
+        """Source w/ bytecode: {}"""
+        py_compile.compile(module.__file__)
+        for result in bench(name, lambda: sys.modules.pop(name), repeat=repeat,
+                            seconds=seconds):
+            yield result
+
+    using_bytecode_benchmark.__doc__ = (
+                                using_bytecode_benchmark.__doc__.format(name))
+    return using_bytecode_benchmark
+
+tabnanny_using_bytecode = _using_bytecode(tabnanny)
+decimal_using_bytecode = _using_bytecode(decimal)
+
+
+def main(import_, options):
+    if options.source_file:
+        with options.source_file:
+            prev_results = json.load(options.source_file)
+    else:
+        prev_results = {}
+    __builtins__.__import__ = import_
+    benchmarks = (from_cache, builtin_mod,
+                  source_writing_bytecode,
+                  source_wo_bytecode, source_using_bytecode,
+                  tabnanny_writing_bytecode,
+                  tabnanny_wo_bytecode, tabnanny_using_bytecode,
+                  decimal_writing_bytecode,
+                  decimal_wo_bytecode, decimal_using_bytecode,
+                )
+    if options.benchmark:
+        for b in benchmarks:
+            if b.__doc__ == options.benchmark:
+                benchmarks = [b]
+                break
+        else:
+            print('Unknown benchmark: {!r}'.format(options.benchmark,
+                  file=sys.stderr))
+            sys.exit(1)
+    seconds = 1
+    seconds_plural = 's' if seconds > 1 else ''
+    repeat = 3
+    header = ('Measuring imports/second over {} second{}, best out of {}\n'
+              'Entire benchmark run should take about {} seconds\n'
+              'Using {!r} as __import__\n')
+    print(header.format(seconds, seconds_plural, repeat,
+                        len(benchmarks) * seconds * repeat, __import__))
+    new_results = {}
+    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'))
+        new_results[benchmark.__doc__] = results
+    if prev_results:
+        print('\n\nComparing new vs. old\n')
+        for benchmark in benchmarks:
+            benchmark_name = benchmark.__doc__
+            old_result = max(prev_results[benchmark_name])
+            new_result = max(new_results[benchmark_name])
+            result = '{:,d} vs. {:,d} ({:%})'.format(new_result,
+                                                     old_result,
+                                              new_result/old_result)
+            print(benchmark_name, ':', result)
+    if options.dest_file:
+        with options.dest_file:
+            json.dump(new_results, options.dest_file, indent=2)
+
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-b', '--builtin', dest='builtin', action='store_true',
+                        default=False, help="use the built-in __import__")
+    parser.add_argument('-r', '--read', dest='source_file',
+                        type=argparse.FileType('r'),
+                        help='file to read benchmark data from to compare '
+                             'against')
+    parser.add_argument('-w', '--write', dest='dest_file',
+                        type=argparse.FileType('w'),
+                        help='file to write benchmark data to')
+    parser.add_argument('--benchmark', dest='benchmark',
+                        help='specific benchmark to run')
+    options = parser.parse_args()
+    import_ = __import__
+    if not options.builtin:
+        import_ = importlib.__import__
+
+    main(import_, options)