https://github.com/tstellar created https://github.com/llvm/llvm-project/pull/77347
When doing a multi-stage PGO build of clang, run the check-clang and check-llvm targets using the instrumented clang and use that profile data for building the final stage2 clang. This is what is recommended by our official documentation: https://llvm.org/docs/HowToBuildWithPGO.html#building-clang-with-pgo I benchmarked this change by compiling the SemaChecking.cpp file from clang. Using check-clang/check-llvm to generate the profile data gives a 25% speedup in the PGO+LTO stage2 clang when compared to the stage1 clang (no-LTO). Prior to this change, I was only seeing ~5% speedup when comparing the stage2 and stage1 builds. >From 127e2ae83f33843cfb9c5cca314afa2fc9844239 Mon Sep 17 00:00:00 2001 From: Tom Stellard <tstel...@redhat.com> Date: Sat, 6 Jan 2024 07:46:01 +0000 Subject: [PATCH] [CMake][PGO] Use check-clang target to generate profdata for PGO builds When doing a multi-stage PGO build of clang, run the check-clang and check-llvm targets using the instrumented clang and use that profile data for building the final stage2 clang. This is what is recommended by our official documentation: https://llvm.org/docs/HowToBuildWithPGO.html#building-clang-with-pgo I benchmarked this change by compiling the SemaChecking.cpp file from clang. Using check-clang/check-llvm to generate the profile data gives a 25% speedup in the PGO+LTO stage2 clang when compared to the stage1 clang (no-LTO). Prior to this change, I was only seeing ~5% speedup when comparing the stage2 and stage1 builds. --- clang/utils/perf-training/CMakeLists.txt | 6 +++--- clang/utils/perf-training/perf-helper.py | 16 +++++++++------- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/clang/utils/perf-training/CMakeLists.txt b/clang/utils/perf-training/CMakeLists.txt index c6d51863fb1b5c..95ff8115aa538b 100644 --- a/clang/utils/perf-training/CMakeLists.txt +++ b/clang/utils/perf-training/CMakeLists.txt @@ -15,7 +15,7 @@ if(LLVM_BUILD_INSTRUMENTED) ) add_custom_target(clear-profraw - COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py clean ${CMAKE_CURRENT_BINARY_DIR} profraw + COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py clean ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_BINARY_DIR}/profiles/ profraw COMMENT "Clearing old profraw data") if(NOT LLVM_PROFDATA) @@ -26,9 +26,9 @@ if(LLVM_BUILD_INSTRUMENTED) message(STATUS "To enable merging PGO data LLVM_PROFDATA has to point to llvm-profdata") else() add_custom_target(generate-profdata - COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py merge ${LLVM_PROFDATA} ${CMAKE_CURRENT_BINARY_DIR}/clang.profdata ${CMAKE_CURRENT_BINARY_DIR} + COMMAND "${Python3_EXECUTABLE}" ${CMAKE_CURRENT_SOURCE_DIR}/perf-helper.py merge ${LLVM_PROFDATA} ${CMAKE_CURRENT_BINARY_DIR}/clang.profdata ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_BINARY_DIR}/profiles/ COMMENT "Merging profdata" - DEPENDS generate-profraw) + DEPENDS generate-profraw check-clang check-llvm) endif() endif() diff --git a/clang/utils/perf-training/perf-helper.py b/clang/utils/perf-training/perf-helper.py index 99d6a3333b6ef0..bd8f74c9c2e129 100644 --- a/clang/utils/perf-training/perf-helper.py +++ b/clang/utils/perf-training/perf-helper.py @@ -30,26 +30,28 @@ def findFilesWithExtension(path, extension): def clean(args): - if len(args) != 2: + if len(args) < 2: print( - "Usage: %s clean <path> <extension>\n" % __file__ + "Usage: %s clean <paths> <extension>\n" % __file__ + "\tRemoves all files with extension from <path>." ) return 1 - for filename in findFilesWithExtension(args[0], args[1]): - os.remove(filename) + for path in args[1:-1]: + for filename in findFilesWithExtension(path, args[-1]): + os.remove(filename) return 0 def merge(args): - if len(args) != 3: + if len(args) < 3: print( - "Usage: %s merge <llvm-profdata> <output> <path>\n" % __file__ + "Usage: %s merge <llvm-profdata> <output> <paths>\n" % __file__ + "\tMerges all profraw files from path into output." ) return 1 cmd = [args[0], "merge", "-o", args[1]] - cmd.extend(findFilesWithExtension(args[2], "profraw")) + for i in range(2, len(args)): + cmd.extend(findFilesWithExtension(args[i], "profraw")) subprocess.check_call(cmd) return 0 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
