If the options are use a sub, or repeat the same code in each place, you will save nothing by avoiding the sub.
Usaing a sub does require that all arguments are put on the stack, and then pulled off again (array opts on <code lang="perl">@_</code>). Not using a sub means the parser has to do that much more work. In a benchmark i did sometime ago, trying to recreate C pre-processor macro, i found the extra parsing time was much longer than the sub stack work.
That aside, there is a way to minimize the main of the function call structure. When passing arrays and hashes, pass references. This makes a single RV (size of a scalar in effect) trasnfer as oposed to an entire array's worth of elements.
Also, as much as i will optimize everything, there has to be a point , i have resently learned, where you figure you will be spending time waiting on the network and disks enough that the changes will not help. So, in short ...
- functions are marginally slow.
- use them anyway
- ob-fu for speed is no better, just un-maintainable
my $cents = 2;
i had a memory leak once, and it ruined my favorite shirt.