The Sampler Busy % metric represents the percentage of time the texture sampler was busy handling texel fetch requests (that is, was either active or stalled).
This metric is unreliable when protected HD media content is being played back on a system with Intel® HD Graphics 5000/ 4600 / 4400 / 4200, Intel® Iris™ graphics 5100, or Intel® Iris™ Pro graphics 5200 configuration.
- If Sampler Busy % is 50, it means that texture sampler was active 50% of the rendering time for the selected ergs.
- If Sampler Busy % is 0, it means that texture sampler was not used or the time during which it was active is very small.
When Sampler Busy % is running this might lead to execution unit stalls, especially if texture fetch latency does not occur in parallel with mathematical instructions (as the shader compiler attempts to optimize shader code to cover such latencies). Examine the EU Stall % metric to see the amount of EUs stalls. If the percentage is high and the Sampler Busy % is close to 100%, most likely you have a texturing bottleneck. Try the 2x2 textures experiment in the Experiments Tab in the Graphics Frame Analyzer to see if this is the case.