On Thu, Jun 03, 2010 at 12:06:39PM +0100, David Woodhouse wrote: > On Tue, 2010-06-01 at 21:36 +0200, Andi Kleen wrote: > > > Collecting the contention/usage statistics on a per spinlock > > > basis seems complex. I believe a practical approximation > > > to this are adaptive mutexes where upon hitting a spin > > > time threshold, punt and let the scheduler reconcile fairness. > > > > That would probably work, except: how do you get the > > adaptive spinlock into a paravirt op without slowing > > down a standard kernel? > > It only ever comes into play in the case where the spinlock is contended > anyway -- surely it shouldn't be _that_ much of a performance issue? The problem is fitting the state into the u32 Also "lightly contended" is not that uncommon. -Andi -- ak@xxxxxxxxxxxxxxx -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
