thoughts.on.code

From the foreword of the 1989 Version of Tandem Computers “Introduction to Performance Analysis” manual:

“Do all things in moderation and nothing to excess”
- Aristotle
Magnitude and limits clearly have their place in performance analysis. Yet there is also the matter of confused perception that must be discussed: mainly performance concepts that appear intuitively valid on the surface but are sure to fail in the test of actual experience.
Performance Analysts will always benefit from periodic challenges no matter how rational or aesthetic they may appear. So maybe John Locke’s quote is appropriate ["God has not been so sparing of men to make them barely two-legged creatures, and left it to Aristotle to make them rational."] At any rate his attitude sparks a receptive chord. People almost always do seem to be the most irrational element of any performance review or analysis.
With this in mind performance analysis should advance simple, proven concepts that experience has shown to be effective. This calls for awareness of some obscure details, a fairly disciplined method and a certain amount of ordinary manual labor.
…
Performance Analysis should seek to define both the adequacy and limits of a system and also strive to obtain the most efficient use of a system. A comprehensive performance review should attempt to discover if the system usage occurs in a prudent (non-wasteful) manner and also determine if resources available can meet performance goals desired.

(all from the first page!)
And another tasty nugget from slightly later on:

“Concurrence is to performance potential what expandability is to capacity potential.” page 4

Yes! I would take it a step farther and add that “Concurrence and loose coupling is to performance potential what expandability is to capacity potential”. By keeping those layers seperate and distinct, you are freeing the code from the bounds of being in the same thread, the same process, the same machine. Layers and components can be completely seperated without the client code knowing about it. Very powerful stuff. There is a great section in Ship It! that talks about this concept further.