* Andy Lutomirski <[email protected]> wrote:
> > Since this patch does add two extra MOVs,
> > I did benchmark these patches. They add exactly one cycle
> > to system call code path on my Sandy Bridge CPU.
>
> Personally, I'm willing to pay that cycle. It could be a bigger
> savings on context switch, and the simplification it enables is
> pretty good.
But, but ... context switches are a relative slow path, compared to
system calls. And I say this with the scheduler maintainer hat on as
well.
So this is not a good bargain IMHO, assuming it's not some _huge_
difference in maintainability - but having an extra percpu field
isn't really much of a problem.
I don't claim that we couldn't in some other situation decide that a
certain type of speedup isn't worth it - but what's the big problem
here? A bit of arithmetics shouldn't be a problem?
Thanks,
Ingo
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