The FS EU Active metric represents the percentage of overall GPU time that the execution units (EUs) were actively executing Fragment Shader instructions.
- If FS EU Active is 50%, it means that half of the overall GPU time was spent actively executing Fragment Shader instructions.
- If FS EU Active is 0%, it means that no Fragment Shader was associated with the selected draw calls, or that the amount of time actively executing Fragment Shader instructions was negligible.
- This metric is important if fragment shading seems to be the bottleneck for selected rendering calls.
- If FS EU Active accounts for most of the EU active time, then to improve performance you might need to simplify the fragment shader.
- If FS EU Active is larger than you would expect and you are encountering slow rendering times, you should examine the fragment shader code for potential reasons why these stalls are occurring.