* Andy Lutomirski <l...@amacapital.net> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/