Re: 90/10 rule... source?

>>> I am looking for a (the) original paper on the 90/10 rule of program
>>> execution. So far I found this reference
>>
>>I think the 90/10 rule might qualify as an urban legend.
>>Example 8 of Knuth's paper quotes a 90% figure, but many of the
>>other examples are around the 50% mark (a few 70%'s).
>
> Yes and no. I think that the rule is real, but it has been made into
> a pseudo law of nature, which it isn't.


What is a pseudo law? One that only applies to a small percentage of
cases?


I think it has more to do with psychology than reality. People tend
to remember those cases where a lot of time was spent in a small
portion of the code. These are cases that are often easier to
optimise (there is a relatively small amount of code to look at);
often resulting in the code not having a 90/10 runtime profile.


>>[I think the 90/10 rule comes from databases, where long before
>>there were computerized files it was well known that in most record
>>systems, a small set of records got most of the lookups. -John]


This sounds like an instance of Zipf's law.


http://linkage.rockefeller.edu/wli/zipf/

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