new micro benchmark for generators

Demos/benchmarks/generators.py

+#!/usr/bin/python
+# micro benchmarks for generators
+
+COUNT = 10000
+
+def count_to(N):
+    for i in range(N):
+        yield i
+
+def round_robin(*iterators):
+    iterators = list(iterators)
+    to_drop = []
+    while iterators:
+        for i, it in enumerate(iterators):
+            try:
+                value = next(it)
+            except StopIteration:
+                to_drop.append(i)
+            else:
+                yield value
+        if to_drop:
+            for index in reversed(to_drop):
+                del iterators[index]
+            del to_drop[:]
+
+def yield_from(*iterators):
+    for it in iterators:
+        yield from it
+
+
+def bm_plain(N):
+    return count_to(COUNT * N)
+
+def bm_round_robin(N):
+    return round_robin(*[ count_to(COUNT // i) for i in range(1,N+1) ])
+
+def bm_yield_from(N):
+    return yield_from(count_to(N),
+                      round_robin(*[ yield_from(count_to(COUNT // i))
+                                     for i in range(1,N+1) ]),
+                      count_to(N))
+
+def bm_yield_from_nested(N):
+    return yield_from(count_to(N),
+                      yield_from(count_to(N),
+                                 round_robin(*[ yield_from(count_to(COUNT // i))
+                                                for i in range(1,N+1) ]),
+                                 count_to(N)),
+                      count_to(N))
+
+
+def time(fn, *args):
+    from time import time
+    begin = time()
+    result = list(fn(*args))
+    end = time()
+    return result, end-begin
+
+def benchmark(N):
+    times = []
+    for _ in range(N):
+        result, t = time(bm_yield_from_nested, 10)
+        times.append(t)
+    return times
+
+if __name__ == "__main__":
+    import optparse
+    parser = optparse.OptionParser(
+        usage="%prog [options]",
+        description=("Micro benchmarks for generators."))
+
+    import util
+    util.add_standard_options_to(parser)
+    options, args = parser.parse_args()
+
+    util.run_benchmark(options, options.num_runs, benchmark)