So my question is: how far can we rely on perl to keep SvREADONLY scalars shared?
Not very far, probably. As noted above, type coersion will still modify the underlying data structure. Also, creating references to the data can make the memory unshared if the SvNULL's REFCNT field is on the same page as the actual data. (IIRC the copy-on-write mechanism is on a per-page basis). That's probably especially relevant if you have a lot of nested data (i.e. much of the data is references).
See also http://gisle.aas.no/perl/illguts/
ps: if you keep the parent process alive and periodically kill and refork children, you might be able to keep this under control. it probably depends a lot on the data and the kind of access you need to it.
-
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.
|