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| author | Rong Xu <xur@google.com> | 2024-11-02 10:51:13 -0700 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2024-11-27 09:38:27 +0900 |
| commit | 2fd65f7afd5a73b685a1651cb651ade120b53e15 (patch) | |
| tree | e086e6e6453d4353c330caecfc3e39f503c801df /scripts | |
| parent | 0847420f5e499a7ab518942fff71482179290163 (diff) | |
| download | lwn-2fd65f7afd5a73b685a1651cb651ade120b53e15.tar.gz lwn-2fd65f7afd5a73b685a1651cb651ade120b53e15.zip | |
AutoFDO: Enable machine function split optimization for AutoFDO
Enable the machine function split optimization for AutoFDO in Clang.
Machine function split (MFS) is a pass in the Clang compiler that
splits a function into hot and cold parts. The linker groups all
cold blocks across functions together. This decreases hot code
fragmentation and improves iCache and iTLB utilization.
MFS requires a profile so this is enabled only for the AutoFDO builds.
Co-developed-by: Han Shen <shenhan@google.com>
Signed-off-by: Han Shen <shenhan@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Sriraman Tallam <tmsriram@google.com>
Suggested-by: Krzysztof Pszeniczny <kpszeniczny@google.com>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Tested-by: Yabin Cui <yabinc@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/Makefile.autofdo | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/scripts/Makefile.autofdo b/scripts/Makefile.autofdo index 6155d6fc4ca7..1caf2457e585 100644 --- a/scripts/Makefile.autofdo +++ b/scripts/Makefile.autofdo @@ -10,6 +10,7 @@ endif ifdef CLANG_AUTOFDO_PROFILE CFLAGS_AUTOFDO_CLANG += -fprofile-sample-use=$(CLANG_AUTOFDO_PROFILE) -ffunction-sections + CFLAGS_AUTOFDO_CLANG += -fsplit-machine-functions endif ifdef CONFIG_LTO_CLANG_THIN @@ -17,6 +18,7 @@ ifdef CONFIG_LTO_CLANG_THIN KBUILD_LDFLAGS += --lto-sample-profile=$(CLANG_AUTOFDO_PROFILE) endif KBUILD_LDFLAGS += --mllvm=-enable-fs-discriminator=true --mllvm=-improved-fs-discriminator=true -plugin-opt=thinlto + KBUILD_LDFLAGS += -plugin-opt=-split-machine-functions endif export CFLAGS_AUTOFDO_CLANG |