The Sampler Texels metric represents the number of texels returned from the texture sampler.
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 Texels is 1000, it means that 1000 texels were delivered to execution units (EUs) from the texture sampler.
A high number of texels fetched from textures leads to a higher texture bandwidth and a higher number of texture sampler unit stalls, which might cause a high number of EU stalls caused by shaders awaiting texels from the sampler unit.
Note that this metric could indicate that the shader stalls while fetching texture data inside branching logic. For example, if the shader fetches texture samples only inside an
if() block in the code, this metric can help you understand how often the shader takes the branch.
This metric is accurate only to four texels, and generally is slightly larger than the actual number of texels used. This is because the texture sampler returns data in 2x2 texel quads. When sampling along angular edges, this inaccuracy becomes more pronounced.