Segmented Scan - Nvidia

Binary Scan
• Often need to scan 1-bit values
— Stream compact: scan true/false flags
— Split / Radix Sort: scan 1-bit flags
• Fermi GPU architecture provides efficient 1-bit warp scan
— int __ballot(int p): 32-bit ―ballot‖ of t/f p from whole warp
— int __popc(int x): count number of 1 bits in x
• Combine with a per-thread mask to get 1-bit warp scan
— Or with no mask for 1-bit warp count