|author||Linus Torvalds <firstname.lastname@example.org>||2011-05-22 14:30:36 -0700|
|committer||Linus Torvalds <email@example.com>||2011-05-22 14:30:36 -0700|
Give up on pushing CC_OPTIMIZE_FOR_SIZE
I still happen to believe that I$ miss costs are a major thing, but sadly, -Os doesn't seem to be the solution. With or without it, gcc will miss some obvious code size improvements, and with it enabled gcc will sometimes make choices that aren't good even with high I$ miss ratios. For example, with -Os, gcc on x86 will turn a 20-byte constant memcpy into a "rep movsl". While I sincerely hope that x86 CPU's will some day do a good job at that, they certainly don't do it yet, and the cost is higher than a L1 I$ miss would be. Some day I hope we can re-enable this. Signed-off-by: Linus Torvalds <firstname.lastname@example.org>
Diffstat (limited to 'init')
1 files changed, 0 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 4986ecc49e65..ffcdad793f14 100644
@@ -908,7 +908,6 @@ endif
bool "Optimize for size"
- default y
Enabling this option will pass "-Os" instead of "-O2" to gcc
resulting in a smaller kernel.