9.6 Optimizing your code
Careful use of the compiler optimize qualities described above may significantly improve the performance of your code. However it is not recommended that you simply experiment with the effect of adding declarations. It is more productive to work systematically:
Use the Profiler, described in The Profiler, to analyse your application's performance and identify bottlenecks, then
Consider whether re-writing of parts of your source code would improve efficiency at the bottlenecks, and
Consider adding suitable declarations as described in this chapter to improve efficiency at the bottlenecks.
The remainder of this section describes some specific ways to produce efficient compiled code with LispWorks.
LispWorks User Guide - 21 Jul 2006