* Davidlohr Bueso <davidl...@hp.com> wrote:
> > Or is access to varied in the Oracle case that it's missing the cache
> > all the time, because the rbtree causes many cachemisses as the
> > separate nodes are accessed during an rb-walk?
>
> Similar to get_cycles(), is there anyway to quickly measure the amount
> of executed instructions? Getting the IPC for the mmap_cache (this of
> course is constant) and the treewalk could give us a nice overview of
> the function's cost. I was thinking of stealing some perf-stat
> functionality for this but didn't get around to it. Hopefully there's an
> easier way...
There's no such easy method I'm afraid (Frederic's probe based trigger
facility will give us that and more - but it's not ready yet) - but you
could try profiling the workload for significant cache-misses:
perf record -e cache-misses ...
I _think_ if it's really catastrophic cache-misses then the rbtree walk
should light up on the perf radar like crazy.
Thanks,
Ingo
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