From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: dan.carpenter@oracle.com, Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
linux-kbuild@vger.kernel.org
Subject: [RFC PATCH] kbuild: Add an option to enable -O1 and speed-up compilation time
Date: Sat, 21 May 2022 11:04:29 +0200 [thread overview]
Message-ID: <23e0ba7863d51ab629498762a97d477645aeafea.1653123744.git.christophe.jaillet@wanadoo.fr> (raw)
Add a new compilation option which speeds-up compilation time.
This can be useful when using static checker such as smatch or build-bots.
In such cases, the speed and quality of the generated code is not
important.
Using -O0 would be even better, but unfortunately, building fails with
this option.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Makefile | 5 ++++-
init/Kconfig | 8 ++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 1f8bef92868f..14467386f947 100644
--- a/Makefile
+++ b/Makefile
@@ -817,7 +817,10 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
-ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
+ifdef CONFIG_CC_OPTIMIZE_FOR_COMPILATION_SPEED
+KBUILD_CFLAGS += -O1
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 1
+else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
KBUILD_CFLAGS += -O2
KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 2
else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
diff --git a/init/Kconfig b/init/Kconfig
index a96776a9b080..3177a1830c9a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1384,6 +1384,14 @@ choice
prompt "Compiler optimization level"
default CC_OPTIMIZE_FOR_PERFORMANCE
+config CC_OPTIMIZE_FOR_COMPILATION_SPEED
+ bool "Optimize for compilation speed (-O1)"
+ help
+ This option can be useful when running a static checker such as smatch
+ or a build-bot.
+ Compilation time is slighly faster than -O2 and it requires less
+ memory.
+
config CC_OPTIMIZE_FOR_PERFORMANCE
bool "Optimize for performance (-O2)"
help
--
2.34.1
next reply other threads:[~2022-05-21 9:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-21 9:04 Christophe JAILLET [this message]
2022-05-21 15:38 ` [RFC PATCH] kbuild: Add an option to enable -O1 and speed-up compilation time Masahiro Yamada
2022-05-23 12:34 ` Changbin Du
2022-05-23 12:50 ` Arnd Bergmann
2022-05-23 18:26 ` Nick Desaulniers
2022-05-23 20:16 ` Christophe JAILLET
2022-05-23 20:31 ` Nick Desaulniers
2022-05-24 14:16 ` Miguel Ojeda
2022-05-23 20:25 ` Miguel Ojeda
2022-05-23 20:44 ` Christophe JAILLET
2022-05-24 14:16 ` Miguel Ojeda
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=23e0ba7863d51ab629498762a97d477645aeafea.1653123744.git.christophe.jaillet@wanadoo.fr \
--to=christophe.jaillet@wanadoo.fr \
--cc=dan.carpenter@oracle.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=masahiroy@kernel.org \
--cc=michal.lkml@markovi.net \
--cc=ndesaulniers@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).