As explained on TechNet, this service collects performance data automatically from local or remote computers. You can then view the data using System Monitor or export the data to spreadsheet programs or databases for analysis and report generation. Note that this service isn’t required to run the Performance Monitor, available as part of the Perfmon utility. If you’re not into viewing all your stats, it’s safe to disable this one, but since it’s set to manual by default, it only starts up when asked for anyway.