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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10
Date: Thu,  7 May 2020 16:45:30 -0600	[thread overview]
Message-ID: <20200507224530.2993316-1-Jason@zx2c4.com> (raw)

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.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 init/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index 9e22ee8fbd75..fab3f810a68d 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)"
-- 
2.26.2


             reply	other threads:[~2020-05-07 22:46 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-07 22:45 Jason A. Donenfeld [this message]
2020-05-08  8:35 ` [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10 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   ` [PATCH v2] " Jason A. Donenfeld
2020-05-12  0:04     ` 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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