27 August 2006
Programming as if Performance Mattered
Posted by Mikhail Esteves under: General .
I frequently see bare queries from programmers in discussion forums, especially from new programmers, who are worried about performance. These worries often stem from popular notions about what operations are “slow.” Division. Square roots. Mispredicted branches. Cache unfriendly data structures. Visual Basic. Inevitably someone chimes in that making out-of-context assumptions, especially without profiling, is a bad idea. And they’re right. But I often wonder if those warnings are also just regurgitations of popular advice. After all, if a C++ programmer was truly concerned with reliability above all else, would he still be using C++?
At the same time, such concerns and advice seem to remain constant despite rapid advances in hardware. A dozen years ago a different crop of new programmers was fretting about the speed of division, square roots, and Visual Basic, and yet look at the hundred-fold increase in computing power since then. Are particular performance problems perennial? Can we never escape them?
This essay is an attempt to look at things from a different point of view, to put performance into proper perspective.