Re: Performance improvement in perl scripts

[BrowserUk]

I have planned to improve the performances in my perl scripts.

Simple. Have them do less and they'll run faster.

I know that sounds cynical, but it isn't. It is a fact of record that when analysing bespoke business software for performance, anything from 40% to 80% of the cycles used by many of those applications, are spent doing non-business critical tasks.

The number 1 culprit is the production of elaborate, detailed and huge log and trace files. Files which cost the business in cpu cycles, storage space, backup and recovery processes and procedures, and which are frequently either: never accessed after they are produced; or only accessed in order to produce 'pretty picture' reports for MIS brochures of little or no value.

The number 2 culprit is the overuse of OO technologies -- intended to promote and simplify reuse -- for critical path elements of software systems that not only never have been reused, but on further analysis, never could be.

When analysing software for performance, look at each subsystem, step and line and determine if it actually contributes directly to the final result or outcome of the process. If not, ask the question: Why is it here? And if the answer starts with some variation of 'If ...'; consider it seriously for removal.

Once you're reduce the programs to doing only that which is actually necessary, then re-profile its runtime performance and only then decide if it is necessary to improve its performance further.