Halve stestr concurrency

To see if reducing the concurrency of tests makes them more reliable,
set them to half the number of cpus (by default, stestr uses the
number of cpus).

Change-Id: I7977c853b759cf980a6717a70876857ef7e9f77e

1 files changed, 1 insertions, 1 deletions

diff --git a/tox.ini b/tox.ini
index 626202301..9e2b5b2d3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,7 +29,7 @@ deps =
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 commands =
-  stestr run {posargs}
+  bash -c 'stestr run --concurrency=`python -c "import multiprocessing; print(int(multiprocessing.cpu_count()/2))"`'
   stestr slowest
 
 [testenv:bindep]