On Mon, 2012-09-24 at 20:10 -0700, Linus Torvalds wrote: > On Mon, Sep 24, 2012 at 7:49 PM, Mike Galbraith <efa...@gmx.de> wrote: > > > > Ah. That's what I did to select_idle_sibling() in a nutshell, converted > > the problematic large L3 packages into multiple ~core2duo pairs, modulo > > shared L2 'course. Bounce proof, and on Westmere, the jabbering back > > and forth in L3 somehow doesn't hurt as much as expected, so the things > > act (more or less, L2 traffic _does_ matter;) like the real deal. > > Right. But your patch *only* looked at the pair. > > Which may be bounce-proof, but we also saw that it was unacceptable.
Yes. Cross wiring traverse _start_ points should eliminate (well, damp) bounce as well without killing the 1:N latency/preempt benefits of large L3 packages. You'll still take a lot of L2 misses while doing futile traverse when fully committed, but that's a separate issue. -Mike -- 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/
