Explicitly document synchronization requirements in Warp-level APIs

For all warp-based cub api, say warpscan, the example given by the document do not use __syncwarp to sync threads within a warp.

However, it seems that in volta, threads within a warp are no longer synchronized naturally and seems __syncwarp is required before and after warp-based communication.

So, need I use __syncwarp for warpscan just like use __syncthreads in blockscan?

Thanks!

Review the documentation and examples for the warp-based CUB APIs mentioned, including WarpScan, and determine the synchronization requirements on Volta and later architectures. Done means the affected API documentation explicitly states whether __syncwarp is required before or after warp-based communication, with examples updated consistently.

Written by the indexing model from the issue text.