RE: FYI -ffreestanding shrinks kernel by 2% on x86_64

David Laight
2019-05-13T09:13:32Z

From: Ingo Molnar
> Sent: 12 May 2019 10:32
...
> Has anyone investigated by any chance where the -ffreestanding space
> savings come from mostly - is it mostly in cold paths, or does it make or
> hot codepaths more efficient as well?
>
> If it's the latter then the kernel would be directly faster as well
> (fewer instructions executed), not just indirectly from better cache
> packing, I suppse?

My guess is that -ffreestanding stops gcc inlining memcpy() (etc).
The calls can be smaller than the inline code, but will (probably)
run more slowly.

David

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