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CPU usage

From: Centaur zeus <perseus_medusa@hotmail.com>
Date: Fri, 25 Jul 2003 08:16:42 +0000
To: www-validator@w3.org
Cc: perseus_medusa@hotmail.com
Message-ID: <LAW8-F75QXTpQqotSJp0000188b@hotmail.com>

Hi all ,

    I am using the linkChecker v 3.6.2.3 and find that it posed quite some 
CPU percentage usage on the server (about 1.5~ 2.0 %). THough it's not a 
large percentage but if I planned to use it for 20 concurrent users than it 
just multiplied. The document I am testing on tried to fetch 61 links.

    I profiled the code and here is the result :
12.9   0.130  0.124   1079   0.0001 0.0001  HTTP::Headers::_header
8.94   0.090  0.128    773   0.0001 0.0002  W3C::CheckLink::start
8.64   0.087  0.265      8   0.0109 0.0332  HTML::Parser::parse
6.95   0.070  0.129     10   0.0070 0.0129  LWP::UserAgent::BEGIN
5.86   0.059  0.388     55   0.0011 0.0071  LWP::Protocol::http::request
3.97   0.040  0.037    292   0.0001 0.0001  URI::_init
3.97   0.040  0.091    641   0.0001 0.0001  HTTP::Headers::header
...

I found that it actually parsed two documents, one is the one I requested 
and another is the one of the html link. So i edit the code and changed
if (being_processed)
to
if (0)
to skip the code

And then, I get the following results :
8.35   0.088  0.405     55   0.0016 0.0074  LWP::Protocol::http::request
5.70   0.060  0.055   1076   0.0001 0.0001  HTTP::Headers::_header
4.75   0.050  0.049    241   0.0002 0.0002  URI::implementor
4.75   0.050  0.119     10   0.0050 0.0119  LWP::UserAgent::BEGIN
4.37   0.046  0.112      7   0.0066 0.0161  HTML::Parser::parse
3.80   0.040  0.092    798   0.0001 0.0001  HTTP::Message::AUTOLOAD

So I want to ask :
1) Why the html link is parsed again ?
2) is it appropriate to change if (being_processed) to if (0) and what's the 
impact ?
3) How can I minimize the resource used by the LWP and HTTP package ?

Thanks.

Perseus

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Received on Friday, 25 July 2003 04:38:13 GMT

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