1. A computer-implemented method for displaying performance data for a computing environment, the method comprising: determining values for a performance metric for a plurality of entities that comprise the computing environment; displaying the computing environment as a set of nodes representing the plurality of entities; and for a selected node in the subset of nodes, displaying a chart with a line illustrating how a value of the performance metric for the selected node varies over time, wherein the line is displayed against a background illustrating how a distribution of the performance metric for a reference subset of the set of nodes varies over time.