[PATCH] D139603: [llvm-profdata] Add option to cap profile output size

[William Junda Huang via Phabricator via llvm-commits]

huangjd added a comment.

The biggest challenge to compute the number of functions accurately is the compression in extbinary, because the compressed size is non-linear to the original size. Since profile samples and function names are written to different sections (and in CS profile the names are split into two sections and samples can also be split into two sections), there is no way to predict ahead the offset between them. Based on use cases, the current heuristic is under estimating how many functions to prune (and the last iteration typically converges to pruning 1 function) so it's unlikely to remove too many functions. (Note: Also tried using cubic equation for heuristic but that will remove too many functions, so the optimal heuristic is between O(n^2) and O(n^3))


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139603/new/

https://reviews.llvm.org/D139603