ChuanqiXu9 wrote: > ### Performance measurements with LLVM > I tested these patches for building LLVM itself with modules > (`LLVM_ENABLE_MODULES=ON`). To work around #130795, I apply #131354 before > building Clang. In terms of overall performance for the entire build, I'm not > able to measure a difference in memory consumption because that is dominated > by the linker. The run time performance is very noisy, so it's hard to make > accurate statements but it looks unaffected as well. > > I did some measurements for individual files, chosen by searching for large > object files and excluding generated files. For each version, I first build > LLVM completely to populate the `module.cache` and then delete and rebuild > only one object file. Run time performance is not hugely affected, it seems > to get slightly faster with this PR. > > `Maximum resident set size (kbytes)` from `/usr/bin/time -v`: > > object file before* `main` this PR > `lib/Analysis/CMakeFiles/LLVMAnalysis.dir/ScalarEvolution.cpp.o` 543100 > 515184 445784 > `lib/Passes/CMakeFiles/LLVMPasses.dir/PassBuilder.cpp.o` 923036 884160 > 805960 > `lib/Transforms/IPO/CMakeFiles/LLVMipo.dir/AttributorAttributes.cpp.o` > 639184 600076 522512 > `lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/SLPVectorizer.cpp.o` > 876580 857404 776572 > before*: reverting > [fb2c9d9](https://github.com/llvm/llvm-project/commit/fb2c9d940ad87e6ae09e06c6915e0c925a4f87ec), > > [c5e4afe](https://github.com/llvm/llvm-project/commit/c5e4afe6733c58e24023ede04275bbed3bde8240), > > [30ea0f0](https://github.com/llvm/llvm-project/commit/30ea0f0ce476bf4c12684a9a514af2ca660bbe44), > > [20e9049](https://github.com/llvm/llvm-project/commit/20e904950967c125abc1e91f57e5a373987ff016) > on current `main`
Out of curiosity, are you saying header modules are helpful to reduce the size of objects? This makes me surprise a little bit. I thought they are only helpful for parsing but not code generating. https://github.com/llvm/llvm-project/pull/133057 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
