Update to support running benchmark on python3

Fixed a TypeError when running with python3, and also added
a 'benchmark3' target to run it on python3 explicitly.

Change-Id: Ia3514465f7d1e97845891cf9aaabcf93e36e0f57

benchmark/benchmark.py

@@ -18,6 +18,7 @@ from __future__ import print_function
 import atexit
 import math
 import os
+import six
 import subprocess
 import sys
 import timeit
@@ -34,6 +35,9 @@ def run_plain(cmd):
                            stdout=subprocess.PIPE,
                            stderr=subprocess.PIPE)
     out, err = obj.communicate()
+    if six.PY3:
+        out = os.fsdecode(out)
+        err = os.fsdecode(err)
     return obj.returncode, out, err
 
 

tox.ini

@@ -44,6 +44,10 @@ exclude = .tox,dist,doc,*.egg,build
 [testenv:benchmark]
 commands = python benchmark/benchmark.py
 
+[testenv:benchmark3]
+basepython = python3
+commands = python3 benchmark/benchmark.py
+
 [testenv:pip-missing-reqs]
 # do not install test-requirements as that will pollute the virtualenv for
 # determining missing packages