[geos-devel] Benchmark between various geometry libraries

[Hartmut Kaiser]

> Thanks for clarifying this, Hartmut.  This makes good sense to me.  In
> my (admittedly limited and dated) experience, the C/C++ heap allocator
> (good ol' malloc still, right?) is pretty slow.  From what you're
> saying
> stack allocation is substantially faster.

It's not that allocation is necessarily slow it's that GEOS is doing _a lot_ non-necessary allocations. And no allocation (putting the instances on the stack results in no allocation) is always faster than the fastest one available :-P

> The kind of change you indicated should be fairly simple to make in the
> GEOS codebase.

Agreed.

> I'd be interested to see how widespread this actually is.  Many of the
> structures that JTS/GEOS creates during processing are shared across
> multiple methods and classes.  I suppose this doesn't preclude using
> stack-based allocation, but mightn't it require passing more references
> down into function calls?

Sharing is certainly a bit trickier this way, but allocating on the stack helps defining proper ownership of the data.

Regards Hartmut

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