For registry operations, these were the numbers found at time the PR was written:
download_blob 108 per second across fleet
v2_auth 180 per second across fleet
catalog 1 per second across fleet
fetch_manifest 205 per second across fleet
list_all_tags 150 per second across fleet
With an average fleet size of 25. As a result, we went with a registry limit of 10r/s (10 * 25 = 250 requests) to bound even the most prolific puller.
Fixes https://jira.coreos.com/browse/QUAY-976