Add test to measure modification time

hdf5/test_modification.py

@@ -0,0 +1,64 @@
+import h5py
+import logging
+import argparse
+import time
+import contextlib
+
+
+
+@contextlib.contextmanager
+def elapsed():
+    start = time.time()
+    yield
+    end = time.time()
+    logging.info("{:.3f} seconds elapsed".format(end - start))
+
+
+def write(name, size):
+    with elapsed():
+        f = h5py.File(name, 'w')
+        dset = f.create_dataset('dset', (size, ), dtype='u1')
+        dset.attrs.create('name', 'some name')
+        dset.attrs.create('number', 42)
+        dset[:] = 123
+        f.flush()
+        f.close()
+        logging.info("Wrote {} bytes to {}".format(size, name))
+
+
+def modify(name):
+    with elapsed():
+        f = h5py.File(name, 'r+')
+        dset = f['dset']
+        dset.attrs.modify('name', 'foo')
+        dset.attrs.modify('number', 23)
+        f.flush()
+        f.close()
+        logging.info("Modified {}".format(name))
+
+
+def main():
+    logging.basicConfig(level=logging.DEBUG)
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--write', action='store_true')
+    parser.add_argument('--modify', action='store_true')
+    args = parser.parse_args()
+
+    files = [('test.1K.h5', 1024),
+             ('test.1M.h5', 1024 * 1024),
+             ('test.10M.h5', 10 * 1024 * 1024),
+             ('test.100M.h5', 100 * 1024 * 1024),
+             ('test.1G.h5', 1024 * 1024 * 1024)]
+
+    if args.write:
+        for name, size in files:
+            write(name, size)
+
+    if args.modify:
+        for name, _ in files:
+            modify(name)
+
+
+if __name__ == '__main__':
+    main()