The metric Post-Filtered Texels represents the number of texels returned from the texture sampler.
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 2×2 texel quads. When sampling along angular edges, this inaccuracy becomes more pronounced.
If Post-Filtered 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 may 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 to understand how often the shader takes the branch.
On Intel® HD Graphics 2500/4000: to access this metric, you must explicitly enable the Intel® Graphics Performance Analyzers option in your BIOS settings:
Select System Agent (SA) Configuration
Select Graphics Configuration
Reboot your machine
If the BIOS on your system does not include the Intel® Graphics Performance Analyzers option, update your BIOS to the latest version from Intel. After completing your performance monitoring activity, we recommend that you disable the Intel® Graphics Performance Analyzers BIOS option and reboot your machine.