This makes us gather a bunch of consistent statistics after we run
tempest that can be use to measure the impact of a given change. These
are stable metrics such as "number of DB queries made" and "how much
memory is each service using after a tempest run."
Note that this will always run after devstack to generate the JSON
file, but there are two things that control its completeness:
- MYSQL_GATHER_PERFORMANCE must be enabled to get per-db stats
- Unless tls-proxy is enabled, we will only get API stats for keystone
Change-Id: Ie3b1504256dc1c9c6b59634e86fa98494bcb07b1
c2772c2984