Maybe valgrind -tool cachegrind can help.
Ciao!
mario
Robert Osfield wrote:
> I am aware of the topic of ordering data structures, but as yet haven't
> spent much time looking at it.
>
> In my sketch ups for an OpenSceneGraph-2.0 minimizing data structure
> size and optimizing ordering have been something to strive for right
> from the start. Performance with complex scene graph are heavily
> dominated by cache missing, memory latency and bandwidth, these issue
> remains totally outweigh FPU performance etc.
>
> Just because I've been thinking about these optimization of data
> structure for an OpenSceneGraph-2.0 doesn't mean we can't steadily
> improve on the existing code base though :-)
>
> It would be very useful to have a data structure analysis tool to gleen
> info about the packing of data, even better what data is accessed most
> often, with such analysis you'd have a good chance at improving the
> later to avoid cache missing, and reduce overall memory bandwidth demands.
>
> Without this tool, one would have to do things by hand and do things by
> trail and error
>
> One thing to consider too is the use of base classes, which provide use
> with generic functionality, they also might be bloating the data
> structure such that the program flow will make requests over quite a
> disperse range of memory to get all it needs. OO programming style
> encourages this where appropriate, but it may be one of the things that
> puts a spanner in the works w.r.t data structures optimized for performance.
>
> Does anybody have recommendation w.r.t anlysis tools? Perhaps we might
> be able to write some ourselves.
>
> Robert.
>
>
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--
Ing. Mario Valle
Visualization Group | http://www.cscs.ch/~mvalle
Swiss National Supercomputing Centre (CSCS) | Tel: +41 (91) 610.82.60
v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax: +41 (91) 610.82.82
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