Two posts back, I was painting pretty pictures of C call overhead. One of the things that I tried later, was just how expensive is just plain old message sending. This is what VisualWorks Smalltalk does fast. I instantiated an object and pounded it with yourself 10,000,000 times. It took about 550ms. To put that in perspective, an simple "argless" int return call takes about 3000ms for the same number. So a C callout is a little more than 5x slower than Smalltalk message sends. Relatively speaking, this actually seems pretty fast. It would be interesting if other environments such as Ruby, Python, and other Smalltalks could compare their C callout speed vs. their own dispatch speed.