First round of optimizations for segment_reduction_op kernels. (#22081)
Summary:
Apply launch bounds annotations for ROCm as the maximum threads per
block (1024) is higher than the ROCm internal default (256).
Reduce the minBlocksPerMultiprocessor for ROCm to 8 from 16 as this
improves performance in some microbenchmarks by (statistically
significant) 4%.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/22081
Differential Revision: D15947426
Pulled By: bddppq
fbshipit-source-id: b4b7015417f99e14dfdedb62639e4d837c38e4fd
