Re: [boost] [xpressive] Performance Tuning?

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?

Interesting...

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.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net