weiwang added a comment. In D101793#2772021 <https://reviews.llvm.org/D101793#2772021>, @yaxunl wrote:
> In D101793#2769297 <https://reviews.llvm.org/D101793#2769297>, @weiwang wrote: > >> Tried to make `Sema::DeclsToCheckForDeferredDiags` `llvm::SmallSetVector`. >> The heap RSS did drop significantly (from peak 100GB to 59GB) , but not as >> good as the current fix (peak 26GB), which makes >> `ASTReader::DeclsToCheckForDeferredDiags` `llvm::SmallSetVector`. >> >> I think the reason is that the duplicated decls are read from multiple >> module file sources (`ASTReader::ReadAST()` -> `ASTReader::ReadASTBlock()`), >> then stored into `ASTReader::DeclsToCheckForDeferredDiags`, then goes into >> `Sema::DeclsToCheckForDeferredDiags` in >> `ASTReader::ReadDeclsToCheckForDeferredDiags()`. Doing dedup at the early >> stage when the decls were just read in `ASTReader` is more effective at >> reducing RSS. > > What if you use SmallSetVector for both Sema::DeclsToCheckForDeferredDiags > and ASTReader::DeclsToCheckForDeferredDiags? Does it cause extra memory usage > compared to using it only for ASTReader::DeclsToCheckForDeferredDiags? Thanks. There would be a slight increase in memory usage since SmallSetVector requires more memory than just SmallVector internally, but given the majority the RSS comes from duplicated decls, I don't think it's an issue by making both SmallSetVector. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D101793/new/ https://reviews.llvm.org/D101793 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
