• 01/27/2020
  • Public Content

Optimize Sampler

Content expert:
Anna Sakharova
Sampling is the process of fetching a value from a texture at a given position. You can configure multiple sampling parameters, such as filtering mode, to balance visual results and sampling performance.
Intel® GPA Graphics Frame Analyzer checks the difference between the percentage of time when a Sampler Input is available and the percentage of time when a Sampler Output is ready.
Metric Name
Description
GPU / Sampler : Slice <N> Subslice<M> Sampler Input Available
Percentage of time there is input from the EUs on slice ‘N’ and subslice ‘M’ to the sampler.
GPU / Sampler : Slice <N> Subslice<M> Sampler Output Ready
Percentage of time there is output from the sampler to EUs on slice ‘N’ and subslice ‘M’.
When Input Available is >10 percent greater than Output Ready for a subslice of a given slice, the sampler is not returning data back to the EUs as fast as it is being requested. The sampler is probably the hotspot. This comparison only indicates a primary hotspot when the samplers are relatively busy, which means that both EU Occupancy and EU Stall are relatively high.
Ingredients
To optimize a Sampler bottleneck, you need the following:
  • Application:
    Unreal Engine 4* Sun Template sample, DirectX SDK* CascadedShadowMaps11 sample
  • Tool:
    Intel® GPA
    Graphics Frame Analyzer
TIP
To download a free copy of the Intel® Graphics Performance Analyzers toolkit, visit the Intel® GPA product page.
  • Operating System:
    Windows* 10
  • GPU:
    Intel® Processor Graphics Gen9 and higher
  • API:
    DirectX* 11
Optimize Sampler Bottleneck with Graphics Frame Analyzer
There can be multiple reasons for the sampler to be a hotspot. To speed up the sampler, you can try the following:
  • Reduce the texture size.
  • Change a filtering mode.
  • Choose a texture format with a smaller amount of data for a pixel or an uncompressed texture format, if possible. In some cases, the uncompressed format may cause a new bottleneck for larger textures.
  • Reduce the number of surfaces on the screen where the texture is applied.
  • Adjust the sampling access pattern to make an access to the texture more linear.
With Intel® GPA Graphics Frame Analyzer you can optimize the Sampler bottleneck with real-time experiments, such as changing texture size and filter parameters in a pixel shader.

See Also

https://docs.microsoft.com/en-us/windows/win32/api/dxgiformat/ne-dxgiformat-dxgi_format
https://docs.microsoft.com/en-us/windows/win32/dxtecharts/cascaded-shadow-maps

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

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