On Fri, Oct 16, 2015 at 06:35:14AM -0700, Andi Kleen wrote: > > > In principle the sequence should work on other CPUs too, but > > > since I only tested on Skylake it is only enabled there. > > > > I would very much like a reduction of the ack states. You introduced the > > late thing, which should also work for everyone, and now you introduce > > yet another variant. > > Ingo suggested to do it this way. Originally I thought it wasn't needed, > but I think now that late-ack made some of the races that eventually > caused Skylake LBR to fall over worse. So in hindsight it was a good idea > to not use it everywhere. > > > I would very much prefer a single ack scheme if at all possible. > > Could enable it everywhere, but then users would need to test it > on most types of CPUs, as I can't.
I think Mike still has a Core2 machine (and I might be able to dig out a laptop), Ingo should have a NHM(-EP), I have SNB, IVB-EP, HSW. So if you could test at least BDW and SKL we might have decent test coverage. Ingo, do you want to first merge the safe patch and then clean up? -- 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/
