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Until more recently, my mental model was a call to `obj.my_method` was basically just a call to `obj.send(:my_method)` behind the scenes. Ruby is all about sending messages to objects, after all. What more explicit way of "send"ing a message was there than to call "send"?! /2

_Semantically_, I think this is still the correct mental model. One obvious difference is that `send` bypasses visibility modifier restrictions, but you can (and should) call `public_send` to achieve the same behavior. But for _performance_, `send` will pretty much always be slower. /3

The reason `obj.my_method` is so much faster, is because of inline caching. I learned about this from byroots JSON optimization series, and from my own work to add a new instruction to the VM. I thought the compiler would do some magic and make them equivalent. /4

Nitpick, the difference is more than 1.5x. In your benchmark, the `.new` shouldn't be part of the bench block.

gist.github.com/byroot/780c1...

Awesome, thanks for the correction! And wow, `public_send`, ouch. Those numbers are rough. I noticed that `send` seems to have a specialized version and `public_send` doesn't, must be related to that somehow?