Intel® VTune™ Amplifier
The metric PS EU Stall % represents the percentage of overall GPU time that the EUs were stalled in Pixel Shader instructions. This metric is important if pixel shading seems to be the bottleneck for selected rendering calls.
This metric does not show total amount of stalled time in the pixel shader, but only the fraction of time when pixel shader stalls caused the entire EU to stall. The entire EU stalls when all of its threads are stalled.
If PS EU Stall % is 50%, it means that half of the overall GPU time was spent stalled on Pixel Shader instructions.
To improve performance: