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Folks,<br>
<br>
In profiling the code I have been working on, trying to understand
why it was running very slowly, I have come across what I expect is
a significant optimisation opportunity. In smokeinvocation.cs, the
function Invoke starts:<br>
<br>
<small><tt> if (signature.StartsWith("operator==")) {</tt><tt><br>
</tt><tt> if (args[1] == null && args[3] ==
null)</tt><tt><br>
</tt><tt> return true;</tt><tt><br>
</tt><tt> else if (args[1] == null || args[3] ==
null)</tt><tt><br>
</tt><tt> return false;</tt><tt><br>
</tt><tt> }</tt><tt><br>
</tt><tt> ModuleIndex methodId;</tt><tt><br>
</tt></small><br>
If you look into it, the function string.StartsWith is a hugely
complicated tree of error checks and nested calls, at least 5 levels
deep, and from what I can tell this call is made for each and every
smoke-invoked call.<br>
<br>
I would suggest, as a minimum, changing it to read:<br>
<br>
<small><tt> if (signature[0] == 'o' &&
signature.StartsWith("operator==")) {</tt><tt><br>
</tt><tt> if (args[1] == null && args[3] ==
null)</tt><tt><br>
</tt><tt> return true;</tt><tt><br>
</tt><tt> else if (args[1] == null || args[3] ==
null)</tt><tt><br>
</tt><tt> return false;</tt><tt><br>
</tt><tt> }</tt><tt><br>
</tt><tt> ModuleIndex methodId;</tt><tt><br>
</tt></small><br>
so as to limit StartsWith calls to only those with a function name
starting with an 'o'. Better, in my view, would be to replace
string.StartsWith (here and possibly elsewhere) with a static
function:<br>
<br>
<small><tt> public static bool HasPrefix(string str, string
pfx)<br>
{<br>
if (str.Length < pfx.Length) return false;<br>
for (int i = 0; i < pfx.Length; i++)<br>
{<br>
if (pfx[i] != str[i])<br>
return false;<br>
}<br>
return true;<br>
}<br>
</tt></small><br>
Which should be significantly faster, by dint of not considering
issues of "culture" and so on. I assume that a null or empty
"signature" arg is not a situation the code should have to cope with
gracefully...<br>
<br>
<br>
I do have a question related to this, though: why use literal
strings for function identification at all? It seems to my limited
understanding of the subject a very odd choice.<br>
<br>
Hope this helps,<br>
Ruth<br>
<pre class="moz-signature" cols="72">--
Software Manager & Engineer
Tel: 01223 414180
Blog: <a class="moz-txt-link-freetext" href="http://www.ivimey.org/blog">http://www.ivimey.org/blog</a>
LinkedIn: <a class="moz-txt-link-freetext" href="http://uk.linkedin.com/in/ruthivimeycook/">http://uk.linkedin.com/in/ruthivimeycook/</a> </pre>
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