Kernel Statistics Tab

The statistics tab gives detailed statistics for the selected kernel for each target device.
To open the statistics tab, expand the desired kernel in the project tree, and double-click the statistics node:

You can see in this statistics output that Northern Islands devices do not use scalar registers (SGPRs and MaxSGPRs are N/A). Northern Islands VGPRs are quad-sized so the 20 VGPRs actually represent 80 float values. You can also see that Southern Islands devices use 44 scalar GPRs that are shared across the wavefront and 49 VGPRs that are used per thread equaling 49 float values.

This view puts the emphasis on giving the programmer the wave constraints based on the SGPRs, VGPRs and LDS size.

In the upper section there is a table that shows the current constraints based on the kernels information for the current selected device.

In the lower section, there is a reference table to help the programmer see the effect of the resources usage on the number of concurrent waves.

The LDS is constructed from the static & dynamic values. The dynamic value can be defined by the user to and its possible effect on the constraint can be immediately viewed. LDS is also affected by local workgroups size, so the values can be changed in order to see the impact on the performance of the kernel.

The middle table shows if the “ISA size” and “Scratch Registers” might have impact on the performance and what are the recommended values.