Performance in Programming – Words of Wisdom

These Performance best practices are the result of multi-role perspectives on software development. There is no ranking for better practices. Some are applied more often and others produce awesome boosts. But what really matters is to apply these practices where they make sense and where the users can benefit the most.

Quote #1

[The First Rule of Program Optimization]

Don’t do it.

[The Second Rule of Program Optimization – For experts only.]

Don’t do it yet.

– Michael Jackson, Michael Jackson Systems Ltd.

Quote #2

The fastest algorithm can frequently be replaced by one that is almost as fast and much easier to understand.

– Douglas W. Jones, University of Iowa

Quote #3

On some machines indirection is slower with displacement, so the most-used member of a structure or a record should be first.

– Mike Morton, Boston, Massachusetts

Quote #4

In non-I/O-bound programs, less than four percent of a program generally accounts for more than half of its running time.

– Don Knuth, Stanford University

Quote #5

Before optimizing, use a profiler to locate the “hot spots” of the program.

– Mike Morton, Boston, Massachusetts

Quote #6

[Conservation of Code Size]

When you turn an ordinary page of code into just a handful of instructions for speed, expand the comments to keep the number of source lines constant.

– Mike Morton, Boston, Massachusetts

Quote #7

If the programmer can simulate a construct faster than the compiler can implement the construct itself, then the compiler writer has blown it badly.

– Guy L. Steele, Jr. Tartan Laboratories

Quote #8

To speed up an I/O bound program, begin by accounting for all I/O. Eliminate that which is unnecessary or rendundant, and make the remaining as fast as possible.

– David Martin, Norristown, Pennsylvania #+endquote

Quote #9

The fastest I/O is no I/O.

– Nils-Peter Nelson, Bell Labs

Quote #10

The cheapest, fastest and most reliable components of a computer system are those that aren’t there.

– Gordon Bell, Encore Computer Corporation

Quote #11

Most assembly languages have a loop operation that does a compare and branch in a single machine instruction; although it was intended for loops, it can sometimes be used to do a general comparison very efficiently.

– Guy L. Steele, Jr. Tartan Laboratories

Quote #12

[Compiler Writer’s Motto – Optimization Pass]

Making a wrong program worse is no sin.

– Bill McKeeman, Wang Institute

Quote #13

Lisp programmers know the value of everything but the cost of nothing.

– Alan Perlis, Yale University

Quote #14

Electricity travels a foot in a nanosecond.

– Commodore Grace Murray Hopper, United States Navy


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