The Reviewbot plugin, after a fresh system restart, takes approximately 5 seconds to run. Progressively throughout the week, the time increases exponentially, eventually taking ~5 minutes per run.
For a company that has ~20 projects all using Reviewbot, this consistently locks down the Master node (the recommended node to run Reviewbot on).
No other builds or jobs see any uptick in build time throughout the week. We do not restart Reviewboard weekly, so we do not believe that to be the culprit.
Attached are two graphs. The first shows the sharp downtick in Reviewbot execution time after a weekly reset of Jenkins. The second shows the gradual CPU usage increase throughout the week (which we believe to be the fault of Reviewbot).