Stream compaction for deferred shading

Jared Hoberock, Victor Lu, Yuntao Jia, John C Hart

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The GPU leverages SIMD efficiency when shading because it rasterizes a triangle at a time, running the same shader on all of its fragments. Ray tracing sacrifices this shader coherence, and the result is that SIMD units often must run different shaders simultaneously resulting in serialization. We study this problem and define a new measure called heterogeneous efficiency to measure SIMD divergence among multiple shaders of different complexities in a ray tracing application. We devise seven different algorithms for scheduling shaders onto SIMD processors to avoid divergence. In all but simply shaded scenes, we show the expense of sortingshaders pays off with better overall shading performance.

Original languageEnglish (US)
Title of host publicationProceedings - High-Performance Graphics 2009
Number of pages8
StatePublished - 2009
EventHigh-Performance Graphics 2009 - New Orleans, LA, United States
Duration: Aug 1 2009Aug 3 2009

Publication series

NameProceedings of the SIGGRAPH/Eurographics Workshop on Graphics Hardware


OtherHigh-Performance Graphics 2009
Country/TerritoryUnited States
CityNew Orleans, LA

ASJC Scopus subject areas

  • Hardware and Architecture
  • Computer Science Applications


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