Re: [patch] measurements, numbers about CONFIG_OPTIMIZE_INLINING=y impact

Linus Torvalds
2009-01-09T19:01:24Z

On Fri, 9 Jan 2009, Andi Kleen wrote:
>
> Ok you're saying we should pay the 4.1% by default for this?

The thing is, YOU ARE MAKING THAT NUMBER UP!

First off, the size increase only matters if it actually increases the
cache footprint. And it may, but..

Secondly, my whole point here has been that we should not rely on gcc
doing things behind our back, because gcc will generally do the wrong
thing. If we decided to be more active about this, we could just choose to
find the places that matter (in hot code) and fix _those_.

Thirdly, you're just replacing _one_ random gcc choice with _another_
random one.

What happens when you say -fno-inline-functions-called-once? Does it
disable inlining for those functions IN GENERAL, or just for the LARGE
ones? See?

Linus