From 3a55fb0d9fe8e2f4594329edd58c5fd6f35a99dd Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Fri, 2 Nov 2012 15:41:01 +0400 Subject: [PATCH] Tell the world we gave up on pushing CC_OPTIMIZE_FOR_SIZE In commit 281dc5c5ec0f ("Give up on pushing CC_OPTIMIZE_FOR_SIZE") we already changed the actual default value, but the help-text still suggested 'y'. Fix the help text too, for all the same reasons. Sadly, -Os keeps on generating some very suboptimal code for certain cases, to the point where any I$ miss upside is swamped by the downside. The main ones are: - using "rep movsb" for memcpy, even on CPU's where that is horrendously bad for performance. - not honoring branch prediction information, so any I$ footprint you win from smaller code, you lose from less code density in the I$. - using divide instructions when that is very expensive. Signed-off-by: Kirill Smelkov Signed-off-by: Linus Torvalds --- init/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 7d30240e5bfe..be8b7f55312d 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1182,7 +1182,7 @@ config CC_OPTIMIZE_FOR_SIZE 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 -- 2.20.1