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That's better but composition is always the devil in the details. Which might be what you mean when you say:

> or neglect to carefully dampen the cross-fade functions

People with a 'caching problem' don't have one cache, they have a bunch of them. So that 1 in 20 chance of getting grey zoned on one cache, is 1 in 400 chance of getting grey zoned on two caches, and a 1 in 8000 chance to get grey zoned on 3. That is a very small fraction but when you're dealing with the Law of Large Numbers that's something that's happening at least once a second for many services.

But if you're using this you probably have a lot more than 3 caches, and then we have to talk about the odds that any request gets grey zoned at least once. which is going to be 1 - (19/20)^n. At six caches you're already over 1 in 4, which is going to potentially change your mean response time quite a bit.




> "...which is going to potentially change your mean response time quite a bit."

My experience is that the changing mean response time isn't nearly as bad as the changing standard deviation.

The really big problems tend to arise when you have unsuspected or under-appreciated positive feedback loops - whether in the software, or in associated physical systems and human behaviors. Or resonance effects. Those situations are where good dampening gets really important.




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