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Entering a very large number

On Mon, 26 Mar 2018 23:49:07 -0400, Richard Damon wrote:

> The bigger issue is that these sort of micro-measurements aren't
> actually that good at measuring real quantitative performance costs.
> They can often give qualitative indications, but the way modern
> computers work, processing environment is extremely important in
> performance, so these sorts of isolated measure can often be misleading.
> The problem is that if you measure operation a, and then measure
> operation b, if you think that doing a then b in the loop that you will
> get a time of a+b, you will quite often be significantly wrong, as cache
> performance can drastically affect things. Thus you really need to do
> performance testing as part of a practical sized exercise, not a micro
> one, in order to get a real measurement.

I think that is so well said, and so important, that I'm replying to the 
post just to quote it even though I have nothing substantial to add to it.