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Re: [RFC PATCH] index-pack: improve performance on NFS




Jeff King <peff@xxxxxxxx> writes:

> Of course any cache raises questions of cache invalidation, but I think
> we've already dealt with that for this case. When we use
> OBJECT_INFO_QUICK, that is a sign that we want to make this kind of
> accuracy/speed tradeoff (which does a similar caching thing with
> packfiles).
>
> So putting that all together, could we have something like:

I think this conceptually is a vast improvement relative to
".cloning" optimization.  Obviously this does not have the huge
downside of the other approach that turns the collision detection
completely off.

A real question is how much performance gain, relative to ".cloning"
thing, this approach gives us.  If it gives us 80% or more of the
gain compared to doing no checking, I'd say we have a clear winner.

> That's mostly untested, but it might be enough to run some timing tests
> with. I think if we want to pursue this, we'd want to address the bits I
> mentioned in the comments, and look at unifying this with the loose
> cache from cc817ca3ef (which if I had remembered we added, probably
> would have saved some time writing the above ;) ).

Yup.