AMD_performance_monitor Finally Hits In RadeonSI

The open-source Intel and Nouveau drivers have already been supporting AMD's OpenGL AMD_performance_monitor extension for exposing performance counters. AMD's own RadeonSI Gallium3D driver is finally joining that party today.

Since 2013 Intel has had support for this AMD-designed OpenGL performance monitoring extension and since earlier this year the open-source NVIDIA driver has supported it too. As of today in Mesa Git master, AMD_performance_monitor is handled by the RadeonSI Gallium3D driver.

Nicolai Hähnle implemented it for CIK+ GPUs on RadeonSI. He explained, "Expose most of the performance counter groups that are exposed by Catalyst. Ideally, the driver will work with GPUPerfStudio at some point, but we are not quite there yet. In any case, this is the reason for grouping multiple instances of hardware blocks in the way it is implemented. The counters can also be shown using the Gallium HUD. If one is interested to see how work is distributed across multiple shader engines, one can set the environment variable RADEON_PC_SEPARATE_SE=1 to obtain finer-grained performance counter groups."

From today's patches I noticed that Nicolai Hähnle is now committing from an AMD.com address. Nicolai had been an open-source graphics driver contributor back around 2009 in the R300 days but from 2010 until last month wasn't active in the Mesa community.