On Tue, 2014-02-11 at 11:40 +0100, Torsten Duwe wrote: > On Tue, Feb 11, 2014 at 03:23:51PM +0530, Raghavendra KT wrote: > > How much important to have holder information for PPC? From my > > previous experiment > > on x86, it was lock-waiter preemption which is problematic rather than > > lock-holder preemption. > > It's something very special to IBM pSeries: the hypervisor can assign > fractions of physical CPUs to guests. Sometimes a guest with 4 quarter > CPUs will be faster than 1 monoprocessor. (correct me if I'm wrong). > > The directed yield resolves the silly situation when holder and waiter > reside on the same physical CPU, as I understand it. > > x86 has nothing comparable.
How is this different from the very ordinary case of an SMP KVM guest whose vcpus are not bound to host cpus, and thus you could have multiple vcpus running on the same host cpu? -Scott -- 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/
