Are there any good, modern, online guides to hand optimizing assembly code? [closed]

Question

I'm working on some code which contains some (compiler generated) chunks of assembly code that we've identified are speed bottle necks.

I know enough about assembly to muddle through and look for manual optimizations - I'm wondering, though, if there are any good, online guides that offer reusable techniques to be used in hand-optimizing assembly. This is not something I expect I'll have to do very often, so odds are I'll have to learn how to do it, again, from scratch, each time.

Answer 1

http://www.agner.org/optimize/optimizing_assembly.pdf

I'd say "have fun", but it would probably be really mean-spirited :(

I think you're interested in Chapter 9, "Optimizing for Speed".