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Re: Performace data and comparison

From: Christian Geuer-Pollmann <geuer-pollmann@nue.et-inf.uni-siegen.de>
Date: Mon, 13 May 2002 16:04:48 +0200
To: reagle@w3.org, merlin <merlin@baltimore.ie>, John Boyer <JBoyer@PureEdge.com>
Cc: w3c-ietf-xmldsig@w3.org
Message-ID: <32008615.1021305888@pinkpanther>
--On Donnerstag, 9. Mai 2002 23:50 +0200 Christian Geuer-Pollmann 
<geuer-pollmann@nue.et-inf.uni-siegen.de> wrote:

> When you look at the results below, you see that each step in the
> xfilter2spec_xfilter2_(1/2/3) adds more processing time, while this is
> not the case for 'my' transform: I can't tell why they are as they are.

I constructed an obfuscated example in which I select some subtrees for 
inclusion/exclusion. To get the final result, I must perform 7 xfilter2 
transforms. Each transform adds more overhead. To test how much each 
transform requires, I ran the test suite 10 times, while the first test 
only did the 1st transform, the second test included the 1st and the 2nd 
transform while the 7th test included all seven steps. The results are 
shown below

10 * apachesample_xfilter2_1     took  5,097 seconds
10 * apachesample_xfilter2_2     took  5,879 seconds
10 * apachesample_xfilter2_3     took  6,790 seconds
10 * apachesample_xfilter2_4     took  7,290 seconds
10 * apachesample_xfilter2_5     took  8,442 seconds
10 * apachesample_xfilter2_6     took  9,503 seconds
10 * apachesample_xfilter2_7     took 10,475 seconds

You can see that the required time is strictly monotonic increasing for 
each added transform step. To check that against my own algorithm, I write 
7 transforms which achieve the same results as the corresponding xfilter2 
ones:

10 * apachesample_apachefilter_1 took  5,207 seconds
10 * apachesample_apachefilter_2 took  5,638 seconds
10 * apachesample_apachefilter_3 took  5,408 seconds
10 * apachesample_apachefilter_4 took  5,478 seconds
10 * apachesample_apachefilter_5 took  5,528 seconds
10 * apachesample_apachefilter_6 took  5,508 seconds
10 * apachesample_apachefilter_7 took  5,358 seconds

You can  see that the time is -- well, not constant, but does not show this 
heavy dependency to take longer for complexer selections.

BTW, if you wanna check this yourself, the implementation of the transform 
[1] is in the Apache CVS, the test suite also [2].

Kind regards,
Christian


[1] 
<http://cvs.apache.org/viewcvs.cgi/xml-security/src/org/apache/xml/security
/transforms/implementations/TransformXPathFilterCHGP.java?rev=1.2&content-t
ype=text/vnd.viewcvs-markup>

[2] 
<http://cvs.apache.org/viewcvs.cgi/xml-security/src_samples/org/apache/xml/
security/samples/TransformPerformanceTester.java?rev=1.3&content-type=text/
vnd.viewcvs-markup>
Received on Monday, 13 May 2002 10:00:15 GMT

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