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

From: Andi Kleen
Date: Fri Jan 09 2009 - 14:21:17 EST


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

It does disable it in general, unless they're marked inline explicitely :

The traditional gcc 2.x rules were:

I Only inline what is marked inline (but it can decide to
not inline)
II Also inline others heuristically only with
-O3 / -finline-functions [which we don't set in the kernel]

Then at some point this additional rule was added:

- Also inline everything static that is only called once
[on the theory that this shrinks code size which is true
according to my measurements]

-fno-inline-functions-called once disables this new rule.
It's very well and clearly defined.

-Andi

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