Comment 2 for bug 1570797

I have performed the simple test. Keystoneclient generates the concurrent queries from the one solely user (admin). It is only connection and no other operation. In Rally world this scenario looks like this:
 "KeystoneAPI.test_01": [
    {
      "runner": {
        "type": "constant",
        "concurrency": 600,
        "times": 4000
      }
]

Env:
3 controllers, 3 compute+storage
OpenStack Release: Mitaka on Ubuntu 14.04
Compute: QEMU
Network: Neutron with VLAN segmentation
Storage Backends:
   Ceph RBD for volumes (Cinder)
   Ceph RadosGW for objects (Swift API)
   Ceph RBD for ephemeral volumes (Nova)
   Ceph RBD for images (Glance)
Capacity: CPU (Cores): 3 (3) RAM 8.9 GB HDD 450.0 GB

The results of the test is shown here:
http://172.18.196.27/s3token/9.08.html#/KeystoneAPI.test_01/overview

In short words, I see that KS is not able to service (in that configuration) more ~500 connections.
I don’t know maybe it’s normal behavior for KS for such workload?
if some botlleneck exists then we should figure out where is the problem.