A good article outlining the location of end points in Reporting Services 2012 integrated mode and how the various bits and pieces talk to each other.
Includes an outline about how to check the Sharepoint Timer job which is used for Reporting Services 2012 Alerting.
If you are looking for Log files, these include Execution logs (Report Server execution log table) and trace logs (file) over here <Drive>:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\LOGS and you can read about the different forms of logging here … http://msdn.microsoft.com/en-us/library/ms156500.aspx.
To configure diagnostic logging for Reporting Services and a number of other Business Intelligence items (e.g. Powerpivot) s, go to Central Administration > Monitoring and select Configure Diagnostic Logging. Select SQL Server Reporting Services from the list, note the landing point for Sharepoint log files above) and click OK.