Re: [GIT] kbuild/lto changes for 3.15-rc1

Linus Torvalds
2014-04-08T22:44:26Z

On Tue, Apr 8, 2014 at 1:49 PM, <josh@joshtriplett.org> wrote:
>
> In addition to making the kernel smaller and such (I'll leave the
> specific stats there to Andi), here's the key awesomeness of LTO that
> you, personally, should find useful and compelling: LTO will eliminate
> the need to add many lower-level Kconfig symbols to compile out bits of
> the kernel.

Actually that, to me, is a negative right now.

Since there's no way we'll make LTO the default in the foreseeable
future, people starting to use it like that is just a bad bad thing.

So really, the main advantage of LTO would be any actual optimizations
it can do. And call me anal, but I want *numbers* for that before I
merge it. Not handwaving. I'm not actually aware of how well - if at
all - code generation actually improves.

Linus