________________________________
> From:
> Date: Thu, 22 Apr 2010 22:59:43 +0200
> To: itext-questions@lists.sourceforge.net
> Subject: Re: [iText-questions] performance follow up
>
>
>
> Hello Mike,
>
> On Apr 22, 2010, at 12:22 PM, Mike Marchywka wrote:
>
> This of course is where you consult Mark Twain. LOL.
> iText is or isn't "better than before" ( for some particular
> use case) irrespective of the data you currently have
> but the question is "does the data allow
> you to reject the conclusion that they are have the same
> execution times with some confidence level?"
>
> Good, this is exactly what I meant :)
>
> Finding ways to explain or attribute the noise into some kind
> of model of course would be a reasonable thing to
> consider if you had a few more test cases with some
> relevant parameters( number of fonts you will need or something).
>
> The performance comparison is based on the representative test case exactly
> as business wants it.
Yes, I know, I'm simply pointing out this is part of a bigger issue
that may or may not be relevant to itext but in general is something
to consider for long tasks. For example, maybe see FFTW.
>
> As far as I know we need only two fonts: light and bold. So the number of
> fonts is not a parameter.
I made that up as a simple strawman. If you make a model for execution
time given some parameters that are important, you can pick
a specific implementation that you expect to be faster. Again a
bit of an extrapolation to make your stats analysis more worthwhile.
> This book is the official reference for the course in Advance System
> Performance Analysis I am taking for my graduate CS Master program in the
> top-10 Technology University of the world ... so no, it is not just equations
> I found in a book :)
LOL, you need to see Allen Greedspan interview, may have been on
CNBC or 60 minutes talking about financial models essentially
saying he didn't understand them but bright PhD's were doing it
so it must be right. The punchline is appeal to authority or credentials
when a factual argument is more ala point. This in fact is how
Mark Twain gets to the front so quickly. Again, I'm not suggesting
you did anything wrong or bad, I haven't actually checked numbers
or given the specific test a lot of thought- 9 data points is usually
not all that conclusive in any case and I guess that's my point.
Presumably you could keep measuring each case with and without patch
and slowly ( sqrt N) get better estimate of average execution times.
Then, end up with 9 data points that are difference in execution time
for each case with/without patch and asymptoticallty measure arbitrarily small
differences. However, it may be more helpful to look
at pictures like histograms or at least run various assumption checks.
You may have non-normal distros and those shapes can tell
you something about causes, not always but it helps to look
before taking one result and running with it.
> Now only 23.8% to go. We only need to make 4 more fixes like the last one and
> the gap will be gone :) The Profiler shows there are still
I wouldn't count on the other one being the final solution to
pdf creation. Do you have symbols info or can you profile it at
all?
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