From: Peter Zijlstra <peterz@infradead.org>
To: ndesaulniers@google.com
Cc: yamada.masahiro@socionext.com, natechancellor@gmail.com,
sedat.dilek@gmail.com, keescook@chromium.org,
samitolvanen@google.com, michal.lkml@markovi.net,
akpm@linux-foundation.org, hannes@cmpxchg.org,
linux@dominikbrodowski.net, npiggin@gmail.com,
mathieu.desnoyers@efficios.com, gor@linux.ibm.com,
adrian@lisas.de, rgb@redhat.com, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, Rui Ueyama <ruiu@google.com>
Subject: Re: [PATCH v2 4/4] Makefile: lld: set -O2 linker flag when linking with LLD
Date: Tue, 12 Feb 2019 13:22:21 +0100 [thread overview]
Message-ID: <20190212122221.GF32494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190211193008.24101-4-ndesaulniers@google.com>
On Mon, Feb 11, 2019 at 11:30:06AM -0800, ndesaulniers@google.com wrote:
> For arm64:
> 0.34% size improvement with lld -O2 over lld for vmlinux.
> 3.3% size improvement with lld -O2 over lld for Image.lz4-dtb.
The Changelog is utterly failing to explain what it does.
> Link: https://github.com/ClangBuiltLinux/linux/issues/343
That is irrelevant crap.
> Suggested-by: Rui Ueyama <ruiu@google.com>
> Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> Changes V1->V2:
> * add tested and reviewed by tags.
>
> Makefile | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/Makefile b/Makefile
> index 00e8e01d23fc..8011555745aa 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -718,6 +718,10 @@ else
> KBUILD_CFLAGS += -Wno-unused-but-set-variable
> endif
>
> +ifdef CONFIG_LD_IS_LLD
> +KBUILD_LDFLAGS += -O2
> +endif
> +
> KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
> ifdef CONFIG_FRAME_POINTER
> KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
> --
> 2.20.1.791.gb4d0f1c61a-goog
>
next prev parent reply other threads:[~2019-02-12 12:22 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 19:30 [PATCH v2 1/4] init/Kconfig: add config support for detecting linker ndesaulniers
2019-02-11 19:30 ` [PATCH v2 2/4] Makefile: clang: choose GCC_TOOLCHAIN_DIR not on LD ndesaulniers
2019-02-16 3:02 ` Masahiro Yamada
2019-02-11 19:30 ` [PATCH v2 3/4] Makefile: lld: tell clang to use lld ndesaulniers
2019-02-13 14:58 ` Masahiro Yamada
2019-02-13 17:41 ` Nick Desaulniers
2019-02-16 3:07 ` Masahiro Yamada
2019-04-02 3:54 ` Nick Desaulniers
2019-04-02 4:49 ` Masahiro Yamada
2019-04-02 7:08 ` [PATCH v3] " Nick Desaulniers
2019-04-02 7:27 ` Nathan Chancellor
2019-04-02 7:33 ` [PATCH v4] " Nick Desaulniers
2019-04-02 7:57 ` Nathan Chancellor
2019-04-02 7:52 ` [PATCH v3] " Sedat Dilek
2019-04-02 7:56 ` Nathan Chancellor
2019-04-05 10:16 ` Masahiro Yamada
2019-04-05 16:11 ` Kees Cook
2019-04-05 16:52 ` Nick Desaulniers
2019-04-07 2:20 ` Masahiro Yamada
2019-02-11 19:30 ` [PATCH v2 4/4] Makefile: lld: set -O2 linker flag when linking with LLD ndesaulniers
2019-02-12 12:22 ` Peter Zijlstra [this message]
2019-02-16 2:55 ` Masahiro Yamada
2019-02-11 19:30 ` [PATCH v2 0/4] Improve kernel LLD support ndesaulniers
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