Source
Structured Programming with go to Statements
A paper by Donald Knuth published in ACM Computing Surveys in December 1974, on program structure and efficiency. It is the source of his often-quoted remark that premature optimization is the root of all evil, together with his advice not to neglect the critical few per cent of a program.
References
Quotes (1)
“We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%.”
— Donald Knuth, "Structured Programming with go to Statements", Computing Surveys 6:4 (December 1974), §1; wording checked against a scan of the paper (the paper prints "3 %")