[QST] Row Contiguous C Matrix from TiledMMA?

What is your question?
Hello!

How do we get a row contiguous value layout from TiledMMA? That is, referring to this LaTeX value layout, we can see that values are interspersed across threads(I believe this helps coalescing?) How can we permute that value layout to achieve column-major contiguity, where Thread 0 owns Vals 0 to N-1; Thread 1, Vals N to 2N - 1 and so on?

My use case requires an independent epilogue operation performed on each row of the C matrix and, naturally, we can parallelize across threads. Currently, I permute the value layout by copying from registers to a shared memory workspace. However, this copy would be unnecessary, if the C matrix values were thread-row contiguous. In addition, I would also be able to operate on the register fragment directly rather than shared memory.

There probably is a memory access tradeoff lurking in the answer to this question, so please let me know if that is the case too :)

Thanks!

Start with the linked CuTe LaTeX value-layout documentation and the TiledMMA layout involved in the C-matrix fragment. Compare its register ownership with the current copy through shared memory, then determine whether a row-contiguous layout or permutation is supported and document the resulting memory-access tradeoff.