diff --git a/tox.ini b/tox.ini
index c433451f1df..ae06aa50ef2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -14,12 +14,11 @@ install_command = pip install {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 
-# Note, we set concurrency to 6 here as a default
-# ostestr will take the last entry for occurence
-# so if you want to increase/decrease this you
-# can simply add concurrency arg to your tox
+# By default ostestr will set concurrency
+# to ncpu, to specify something else use
+# the concurrency=<n> option.
 # call ie: 'tox -epy27 -- --concurrency=4'
-commands = ostestr --concurrency=6 {posargs}
+commands = ostestr {posargs}
 
 whitelist_externals = bash
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY