Nouveau Lands GL_AMD_Performance_Monitor Support

Thanks to work by Samuel Pitoiset, NVIDIA's hardware performance counters of their recent GPU generations are now being exposed through the open-source Nouveau Linux graphics driver.

For many months Samuel has been working on reverse-engineering the NVIDIA performance counters and working toward an open-source NVPerfKit-like implementation. Samuel made a lot of progress in 2014 and finally some of the fruits of that work are landing in Mesa for the user-space side.

There is now GL_AMD_performance_monitor support within Mesa's state tracker to Gallium3D. Intel's Mesa DRI driver has long exposed this extension for exposing performance/profiling information to OpenGL applications while finally it's been ported to the Mesa ST for use by Gallium3D drivers. Adding this extension was done by Christoph Bumiller.

Samuel then exposed support for the MP counters via GL_AMD_performance_monitor with the NVC0 driver for Fermi hardware and newer. This change is coming for the Mesa 10.6 release that shouldn't be too much further out.

Maybe next we'll see the R600/RadeonSI Gallium3D drivers from AMD implement support for the GL_AMD_performance_monitor extension.