On Fri, Aug 31, 2018 at 12:49:45PM +0200, Peter Zijlstra wrote: > On Fri, Aug 31, 2018 at 08:32:34PM +1000, Nicholas Piggin wrote: > > Oh gee, I suppose. powerpc hash is kind of interesting because it's > > crazy, Aneesh knows that code a lot better than I do. radix modulo > > some minor details of exact instructions is fairly like x86 > > The whole TLB broadcast vs explicit IPIs is a fairly big difference in > my book. > > Anyway, have you guys tried the explicit IPI approach? Depending on how > IPIs are routed vs broadcasts it might save a little bus traffic. No > point in getting all CPUs to process the TLBI when there's only a hand > full that really need it. > > OTOH, I suppose the broadcast thing has been optimized to death on the > hardware side, so who knows..
You also can't IPI an IOMMU or a GPU ;) Will