Fw: [PATCH][RFC] CC_OPTIMIZE_FOR_SIZE should default to N

Paul E. McKenney paulmck at linux.vnet.ibm.com
Sun Mar 6 01:55:49 UTC 2011


Thoughts?

							Thanx, Paul

----- Forwarded message from Jesper Juhl <jj at chaosbits.net> -----

Date: Sun, 6 Mar 2011 00:49:58 +0100 (CET)
From: Jesper Juhl <jj at chaosbits.net>
To: linux-kernel at vger.kernel.org
cc: Andrew Morton <akpm at linux-foundation.org>,
	"Paul E. McKenney" <paulmck at linux.vnet.ibm.com>,
	Ingo Molnar <mingo at elte.hu>,
	Daniel Lezcano <daniel.lezcano at free.fr>,
	Eric Paris <eparis at redhat.com>,
	Roman Zippel <zippel at linux-m68k.org>
Subject: [PATCH][RFC] CC_OPTIMIZE_FOR_SIZE should default to N

I believe that the majority of systems we are built on want a -O2 compiled 
kernel. Optimizing for size (-Os) is mainly benneficial for embedded 
systems and systems with very small CPU caches (correct me if I'm wrong).
So it seems wrong to me that CC_OPTIMIZE_FOR_SIZE defaults to 'y' and 
recommends saying 'Y' if unsure. I believe it should default to 'n' and 
recommend that if unsure. People who bennefit from -Os know who they are 
and can enable the option if needed/wanted - the majority shouldn't 
select this. Right?

Signed-off-by: Jesper Juhl <jj at chaosbits.net>
---
 Kconfig |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index be788c0..7e16268 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -886,12 +886,12 @@ endif

 config CC_OPTIMIZE_FOR_SIZE
 	bool "Optimize for size"
-	default y
+	default n
 	help
 	  Enabling this option will pass "-Os" instead of "-O2" to gcc
 	  resulting in a smaller kernel.

-	  If unsure, say Y.
+	  If unsure, say N.

 config SYSCTL
 	bool


-- 
Jesper Juhl <jj at chaosbits.net>            http://www.chaosbits.net/
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