https://support.microsoft.com/en-au/topic/kb3044160-fix-performance-counters-under-reportserver-service-object-show-zero-in-ssrs-2014-41d23371-6cc1-626c-9435-13bd5fb6efe0
KB3044160 - FIX: Performance counters under "ReportServer:Service" object show zero in SSRS 2014 -...
Fixes an issue that occurs on a server that has SSRS 2014 installed.