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Subject: Re: [boost] [xpressive] Performance Tuning?
From: Joel de Guzman (joel_at_[hidden])
Date: 2009-07-20 00:12:31

Edward Grace wrote:

> N.B. The final timing of qi_parse against itself is zero percent within
> the nominal precision. At first I thought the 1000% speedup of qi_parse
> was a fake due to some compiler shenanigans. Now I don't think so. I
> think it really is that much faster for small buffers! Note that this
> timing experiment took ~6mins.


> Same results - actually better since the experiment is quicker and the
> 95th percentile range is therefore narrower. Obviously I'm suspicious
> that something funny's going on - would you expect it to be capable of
> being ~10x faster?


It seems that spatial locality strongly favors optimized Spirit
code very well -- best when the data structure can reside fully
in the cache. Try bumping the size incrementally and I expect a
big dip in performance at a certain point.


Joel de Guzman

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