Sampler Bottleneck %

The Sampler Bottleneck % metric represents the percentage of time that the texture sampler is a bottleneck. The sampler is stalling Execution Units (EUs) due to a full input FIFO and starving EUs due to a lack of results.

NOTE

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.

Examples

If Sampler Bottleneck % is 90, then the texture sampler is a bottleneck (stalling some EUs and/or causing other EUs to idle) 90% of the time.

Improving Performance

The following techniques may improve the texture sampler performance:

  • Reducing the size of textures, by using a lower resolution or lower color precision (such as RGBA4444 instead of RGBA8888)
  • Using texture compression to reduce the amount of memory to transfer textures
  • Using mipmapping, so that smaller textures (mipmaps) can be used
  • Reducing the number of textures in the scene
  • Using a different filtering algorithm

For example, anisotropic filtering is more expensive to compute than a simpler algorithm, such as bilinear filtering. To help minimize overhead in this area, capture a typical frame while the game is running, use this frame as input to the Graphics Frame Analyzer, and try one or more of the following techniques:

  • the 2x2 Textures experiment in the Experiments tab to see if textures are a bottleneck
  • the Texture tab to see the texture size, format, and mip level

NOTE

This metric might show incorrect results and will be disabled with the next driver update.

See Also

2x2 Texture
Texture Tab

For more complete information about compiler optimizations, see our Optimization Notice.