Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2009-07-28 10:14:16

Edward Grace wrote:
>
> >> Does the size of the test data set matter?  In other words do you
> >> notice similar speedups if the test data will all fit in cache?
> >
> > Wouldn't that give less representative performance results?
>
> I guess it depends what you're trying to represent when
> measuring the performance.  If you're trying to represent the
> [totally contrived] case of parsing short segments of text that
> all fit in cache surely it's better?

I was presuming to suggest that the more representative test was
that of parsing across the spectrum of possible inputs such code
likely will parse in a real finance program rather than
contriving small tests to focus on isolated characteristics.

> Or is your question more regarding the distribution of the
> actual values under test rather than the length?

I don't think the lengths will vary much beyond what appears in
the test input other than, possibly, the lack of really short
inputs.

> My suggestion is merely the curiosity of seeing if there is a
> cache dependent effect or not rather than a 'representative'
> measurement.  I don't for a minute think it's a good idea to
> permanently modify someone's hard thought through and
> exhaustive testing.

I was afraid that the test code might be permanently altered and
lose sight of what I think is a fairly representative set of
test inputs.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer, Core Software      using std::disclaimer;
Susquehanna International Group, LLP  http://www.sig.com

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