Reducing CPU usage

[James Pearson]

Excerpts from Simon Lyall's message of 2012-12-18 14:10:37 -0800:
> On Tue, 18 Dec 2012, James Pearson wrote:
> > Towards the end, you mention moving a rule from being of the form
> >
> >    if ((a || b ) && c) {
> >
> > to
> >
> >     if (a || b) {
> >         if (c) {
> >
> > , where c is an expensive check and (a || b) rules out most pages, and seeing a
> > CPU usage decrease.  This seems odd to me, since I'd expect short-circuiting to
> > cut out the check for c if (a || b) is false.
> 
> In reality what I did was closer to changing:
> 
> if ((a || b ) && c) { }
> if ((a || b ) && d) { }
> if ((a || b ) && e) { }
> 
> to:
> 
> if (a || b) {
>    if (c) { }
>    if (d) { }
>    if (e) { }
> }
> 
> where c,d & e were large regex functions. The test ( a || b ) was matched 
> about 14% of the time.

Ok, that makes more sense.  Thanks for the clarification.