svn commit: r190837 - in stable/7/sys: . contrib/pf dev/ath/ath_hal dev/cxgb kern

[Attilio Rao]

2009/4/8, Robert Watson <rwatson at freebsd.org>:
> On Wed, 8 Apr 2009, Stephen McKay wrote:
>
>
> > Author: mckay
> > Date: Wed Apr  8 04:30:16 2009
> > New Revision: 190837
> > URL: http://svn.freebsd.org/changeset/base/190837
> >
> > Log:
> >  MFC r187460: Add a limit on namecache entries.
> >
>
>  Obviously, having a limit is a good idea, but I wonder if we should use
> some more mature scheme to limit entries.  At the very least, using UMA zone
> limits may help memory being dedicated to cache entries without being able
> to actually use it (i.e., extra entries in the UMA cache above the
> desiredvnodes limit).
>
>  Similarly, the cost of different cache entries is different -- long entries
> cost much, much more than short ones, because we use two bucket sizes.
> Perhaps this means that we should separately count long and short entries,
> and short ones should contribute less towards the limit than long ones?
>
>  Finally, I think it would be a good idea to do a bit of real-world
> profiling on memory efficiency of the name cache: how much memory is wasted
> when assumptions about short/long are wrong, and could we retune lengths,
> limits, hash bucket counts, etc, to work better in practice?

Am I wrong or you were working on adding DTrace tracing to it?
Do you have any interesting workload/numbers you can show?

Thanks,
Attilio


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