To output statistics, check Render Statistics option in your RenderMan RIS ROP's Options | Statistics Tab:

By default, it uses the Disk File's path and base name. 

You can view the output xml file with any web browser.  See Diagnostics for more information.

• File: Generate a .stats file 
• XML File: Generate an XML file for viewing in a browser
• IO Trace Filename: A detailed input/output report saved as XML
• Stylesheet: The stylesheet used for formatting an XML file
• Shader Profile: Profile for custom shader output
• Displace Ratios: Suppress reporting of displacement values when divided by the max displacement fall inside this range
• Maximum Displacement: The number of warnings for displacement values to print before stopping, 0 means all values reported
• Enable Texture Statistics: Allows finer grained reporting of texture usage
• Track Asset Objects: Tracks scene entities