Messages in this thread | | | Date | Tue, 11 Feb 2014 11:40:30 +0100 | From | Torsten Duwe <> | Subject | Re: [PATCH v2] powerpc ticket locks |
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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.
Torsten
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