Vulkan mbcnt Sample

SDKs & Libraries

This sample shows how to use the AMD_shader_ballot extension and mbcnt to perform a fast reduction within a wavefront.

For more information about Vulkan, visit GPUOpen’s Vulkan page.

Extension details

  • mbcnt computes the number of bits set in the provided argument, masked with a thread mask which contains 1 for all active threads less than the current thread within a wavefront.
  • ballot returns a 64-bit mask which contains 1 if that thread within the wavefront passed true into the instruction, and 0 otherwise.

System requirements

  • AMD Radeon™ GCN-based GPU (HD 7000 series or newer)
    • Or other Vulkan™ compatible discrete GPU
  • 64-bit Windows® 7 (SP1 with the Platform Update), Windows® 8.1, or Windows® 10
  • Visual Studio® 2013 or Visual Studio® 2015
  • Graphics driver with Vulkan support
    • For example, AMD Radeon Software Crimson Edition 16.5.2 or later
  • The Vulkan SDK must be installed

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