Mario Gonzalez commented on merge request !17 at KOTO L3 / L3 software

Mario Gonzalez
2025-12-18T17:33:43Z

Thanks for having done all the tests, that is very nice.

I wonder if we are not seeing a performance difference because the tests are limited by something other than the memory bandwidth. Say for example that all 16 threads read from global memory truly in parallel. Then, if we only measure execution time, we will get the same performance as when doing the read with thread 0 only. However one approach consumes 16x more bandwidth than the other. So if the GPU is busy enough at a given time (which might not be the case in your test), the extra memory accesses might affect the overall HLT performance.

To see if this is true or not without saturating the whole HLT, we could see how the kernel execution time scales with the number of blocks and/or threads per block.

Many thanks for pointing out all other places where this should be addressed. Maybe we can follow up that by opening an issue, and address it in a future PR (since this is not very related to the compression)? I will be happy to help with the benchmarks, as this is as well quite interesting to me :)