
How can more layers be more efficient? - tosh
http://www.lispcast.com/more-layers
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kazinator
How can layers be more efficient?

Let's see: your computer's multiple layers of caches in the "memory hiearchy"
are all extra layers between the processor core and memory.

If you were to turn these off, it would be a complete slug.

Layers are faster when they can intelligently:

* filter requests (higher layer blocks some useless request avoiding time-wasting calls into lower layers where the same conclusion will eventually be reached).

* aggregate requests (the higher layer notices that multiple small/incremental requests can be rewritten to an aggregate request that is available in the vocabulary of the lower layer; I/O buffering is a common example of this).

* provide caching (already covered)

* provide bypass. A system with N layers can be faster with N+1 layers if the new layer is able to bypass some of the layers below it in some cases.

* use alternative providers for the lower level services. Related to bypass: for this situation, don't use all these existing layers; go this way instead.

