Amir added a comment. Hi Petr, thank you for your comments!
In D132975#3763264 <https://reviews.llvm.org/D132975#3763264>, @phosek wrote: > This was already on my list of build system features I'd like to implement > and I'm glad someone else is already looking into it, thank you! I have two > high level comments about your approach. > > The first one is related to the use of Clang build as the training data. I > think that Clang build is both unnecessarily heavyweight, but also not > particularly representative of typical workloads (most Clang users don't use > it to build Clang). Ideally, we would give vendors the flexibility to supply > their own training data. I'd prefer reusing the existing perf-training > <https://github.com/llvm/llvm-project/tree/main/clang/utils/perf-training> > setup to do so. In fact, I'd imagine most vendors would likely use the same > training data for both PGO and BOLT and that use case should be supported. Agree that perf-training might be useful for vendors. I'll try to enable it in a follow-up diff. Please note that the target for profile collection is not hardcoded to clang, it's configurable via CLANG_BOLT_INSTRUMENT_PROJECTS and CLANG_BOLT_INSTRUMENT_TARGETS. Right now it's the llvm/not tool (the smallest possible). Also, that the > The second one is related to applicability. I don't think this mechanism > should be limited only to Clang. Ideally, it should be possible to instrument > and optimize other tools in the toolchain distribution as well; LLD is likely > going to be the most common one after Clang. I thought about it, and I think we can accommodate optimizing arbitrary targets is by providing an interface to instrument specified target(s) via `-DBOLT_INSTRUMENT_TARGETS`. For each of the target binaries, CMake would create targets like `bolt-instrument-$TARGET` and `bolt-optimize-$TARGET`. For `bolt-instrument-$TARGET`, BOLT would instrument the target binary, placing instrumented binary next to the original one (e.g. `target`-bolt.inst). End users would use those instrumented binaries on representative workloads to collect the profile. For `bolt-optimize-$TARGET`, BOLT would post-process the profiles and create optimized binary (`target`-bolt). I appreciate your suggestions. Do you think we can move incrementally from this diff towards more general uses in follow-up diffs? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D132975/new/ https://reviews.llvm.org/D132975 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
