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SubjectRe: [patch 2.6.13-rc3a] i386: inline restore_fpu


On Sat, 23 Jul 2005, Chuck Ebbert wrote:
>
> This patch (may not apply cleanly to unpatched -rc3) drops overhead
> a few more percent:

That really is pretty ugly.

I'd rather hope for something like function-sections to just make games
like this be unnecessary. The linker really should be able to do things
like this for us (ie if it sees that the only reference to a function is
from another function, it should be able to just put them next to each
other anyway).

And yes, I realize that "should be able" isn't the same thing as "does",
but the thing is, doing it by hand ends up being a maintenance problem in
the long run. It also misses all the other cases where it might be
beneficial, but where you don't happen to run the right benchmark or look
at the right place.

So maybe a few hints to the binutils people might just make them go: "try
this patch/cmdline flag", and solve many more problems. They likely have a
lot of this kind of code _already_, or have at least been thinking about
it.

I personally believe that there's likely a lot more to be had from code
(and data) layout than there is from things like alias analysis or
aggressive inlining.

Linus
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