From outside the box it looks like Perl is creating an intermediate list between the two maps and somewhere before 5e5 elements the system starts swapping. Before the swapping starts the page faults happen when more memory is needed to extend the lists giving about 3500 bytes per fault - close enough to a 4K page size perhaps. At some point the lists get too big to stay resident and the system starts swapping with the resultant increase in page faults (now against non-resident pages) and consequent increase in time (due to the page fetches from disk).
What seems very odd is that it is happening on a 64 bit system with (I presume) plenty of ram! However I get very similar results with a 32 bit Windows system and 5.10.1 btw.
True laziness is hard work
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|