Messages in this thread | | | Date | Fri, 10 Dec 2010 15:45:15 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [BUG] 2.6.37-rc3 massive interactivity regression on ARM |
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On Fri, 10 Dec 2010, Eric Dumazet wrote:
> > There is certainly a major difference in that execution of a stream of > > instructions on the same cpu is guaranteed to have a coherent view of > > the data. That is not affected by interrupts etc. > > > > We dont care of interrupts. We care of doing a transaction over a > complex set of data, that cannot be done using an atomic op (or we need > a spinlock/mutex/rwlock), and should not because of performance.
So what? The cpu gives you incoherent view of data somewhere when only processing data from a single cpu?
If you have remote data accesses (loop summing the data?) and you have to be concerned about data coherence then you CANNOT use this_cpu_ops since they are not guaranteed to be coherent to other processors.
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