Add --no-container option

Motivation:

If mdbench is run on a single node, the extra directory is unnecessary

Modification:

Add --no-container option to avoid creating the mdbench.x.y directory.

Default behaviour remains unchanged

Result:

Possible to avoid creating an unnecessary directory.

mdbench.py

@@ -19,6 +19,7 @@
     -d, --dirs  <N>  : number of generated directories to generate
     -s, --size  <N>  : size of generated files in B/K/M/G
     -n, --no-clean   : do not delete created files and directories
+    --no-container   : do not create the 'mdbench.<name>.<pid>' directory
     -h, --help       : help message
 
   and PATH points to the directory where tests should run. Current directory
@@ -128,10 +129,11 @@ def main():
 	file_count = FILE_COUNT
 	file_size = FILE_SIZE
 	cleanup = True
+	createContainer = True
 
 	try:
 		options, remainder = getopt.gnu_getopt(sys.argv[1:], 'f:d:s:nh', \
-					 ['files=','dirs=','size=','no-clean','help'])
+					 ['files=','dirs=','size=','no-clean','no-container','help'])
 	except getopt.GetoptError as err:
 		print str(err)
 		usage()
@@ -145,6 +147,8 @@ def main():
 			file_size = get_size(arg)
 		elif opt in ('-n', '--no-clean'):
 			cleanup = False
+		elif opt in ('--no-container'):
+			createContainer = False
 		elif opt in ('-h', '--help'):
 			usage()
 
@@ -153,9 +157,11 @@ def main():
 
 	path = remainder[0]
 
-	root = '%s/mdbench.%s.%d' % (path, socket.gethostname(), os.getpid())
+	root = '%s/mdbench.%s.%d' % (path, socket.gethostname(), os.getpid()) if createContainer else path
+
+	if createContainer:
+		os.mkdir(root)
 
-	os.mkdir(root)
 	elapsed, result = bench_run( make_dirs, root, dir_count )
 	in_sec = total_seconds(elapsed)
 	print '%.2f dir creates per second' % (dir_count/in_sec)
@@ -177,7 +183,8 @@ def main():
 		in_sec = total_seconds(elapsed)
 		print '%.2f dir removes per second' % (dir_count/in_sec)
 
-		os.rmdir(root)
+		if createContainer:
+			os.rmdir(root)
 
 if __name__ == '__main__':
 	main()