From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: linux-kernel@vger.kernel.org
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
linux-kbuild@vger.kernel.org, x86@kernel.org,
stable@vger.kernel.org, hjl.tools@gmail.com,
Peter Zijlstra <peterz@infradead.org>,
Jakub Jelinek <jakub@redhat.com>,
Oleksandr Natalenko <oleksandr@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
David Laight <David.Laight@aculab.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>
Subject: [PATCH v2] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10
Date: Mon, 11 May 2020 15:57:20 -0600 [thread overview]
Message-ID: <20200511215720.303181-1-Jason@zx2c4.com> (raw)
In-Reply-To: <20200508090202.7s3kcqpvpxx32syu@butterfly.localdomain>
GCC 10 appears to have changed -O2 in order to make compilation time
faster when using -flto, seemingly at the expense of performance, in
particular with regards to how the inliner works. Since -O3 these days
shouldn't have the same set of bugs as 10 years ago, this commit
defaults new kernel compiles to -O3 when using gcc >= 10.
Cc: linux-kbuild@vger.kernel.org
Cc: x86@kernel.org
Cc: stable@vger.kernel.org
Cc: hjl.tools@gmail.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Laight <David.Laight@aculab.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
Changes v1->v2:
- [Oleksandr] Remove O3 dependency on ARC.
init/Kconfig | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index 9e22ee8fbd75..f76ec3ccc883 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1245,7 +1245,8 @@ config BOOT_CONFIG
choice
prompt "Compiler optimization level"
- default CC_OPTIMIZE_FOR_PERFORMANCE
+ default CC_OPTIMIZE_FOR_PERFORMANCE_O3 if GCC_VERSION >= 100000
+ default CC_OPTIMIZE_FOR_PERFORMANCE if (GCC_VERSION < 100000 || CC_IS_CLANG)
config CC_OPTIMIZE_FOR_PERFORMANCE
bool "Optimize for performance (-O2)"
@@ -1256,7 +1257,6 @@ config CC_OPTIMIZE_FOR_PERFORMANCE
config CC_OPTIMIZE_FOR_PERFORMANCE_O3
bool "Optimize more for performance (-O3)"
- depends on ARC
imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives
help
Choosing this option will pass "-O3" to your compiler to optimize
--
2.26.2
next prev parent reply other threads:[~2020-05-11 21:57 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 22:45 [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10 Jason A. Donenfeld
2020-05-08 8:35 ` Peter Zijlstra
2020-05-08 9:02 ` Oleksandr Natalenko
2020-05-08 11:21 ` Jason A. Donenfeld
2020-05-08 11:33 ` Oleksandr Natalenko
2020-05-08 11:49 ` Arnd Bergmann
2020-05-08 12:07 ` Jason A. Donenfeld
2020-05-08 13:04 ` Arnd Bergmann
2020-05-08 15:06 ` Joe Perches
2020-05-08 15:09 ` Arnd Bergmann
2020-05-10 12:47 ` David Laight
2020-05-10 17:45 ` Joe Perches
2020-05-10 18:58 ` David Laight
2020-05-12 1:10 ` Masahiro Yamada
2020-05-11 21:57 ` Jason A. Donenfeld [this message]
2020-05-12 0:04 ` [PATCH v2] " Linus Torvalds
2020-05-12 0:09 ` Linus Torvalds
2020-05-12 0:43 ` Jason A. Donenfeld
2020-05-12 8:44 ` Richard Biener
2020-05-13 11:27 ` [PATCH] " Artem S. Tashkinov
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