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    SubjectRe: [PATCH 2/2] smp_call_function: use rwlocks on queues rather than rcu
    Paul E. McKenney wrote:

    >> RCU is problematic because it lets cachelines get cold. A hot cacheline that
    >> is used frequently read and written to by the same cpu is very good thing for
    >> performace.
    > So on your these large boxes, read-only cachelines are preferentially
    > ejected from the cache, so that one should write to per-CPU data
    > occasionally to keep it resident? Or is the issue the long RCU grace
    > periods which allow the structure being freed to age out of all relevant
    > caches? (My guess would be the second.)

    The issue are the RCU grace period that are generally long enough to make the
    cacheline fall out of all caches.

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      Last update: 2008-08-22 19:23    [W:0.036 / U:0.380 seconds]
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