On Fri, Apr 20, 2007 at 01:03:22PM -0700, William Lee Irwin III wrote: > On Fri, 20 Apr 2007, William Lee Irwin III wrote: > >> I'm not really convinced it's all that worthwhile of an optimization, > >> essentially for the same reasons as you, but presumably there's a > >> benchmark result somewhere that says it matters. I've just not seen it. > > On Fri, Apr 20, 2007 at 12:44:55PM -0700, Christoph Lameter wrote: > > If it is true that we frequently remotely write the per cpu runqueue > > data then we may have a NUMA scalability issue. > > From the discussion on Suresh's thread, it appears to have sped up a > database benchmark 0.5%. > > Last I checked it was workload-dependent, but there were things that > hammer it. I mostly know of the remote wakeup issue, but there could > be other things besides wakeups that do it, too.
remote wakeup was the main issue and the 0.5% improvement was seen on a two node platform. Aligning it reduces the number of remote cachelines that needs to be touched as part of this wakeup. thanks, suresh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
