Evolution, not revolution: a look at AMD's Bulldozer
@ 2010/08/25AMD's official line on Bulldozer is that it's a "third way" between traditional multicore and simultaneous multithreading (SMT). In the former type of design (also called chip multiprocessing, or CMP), each concurrently running thread runs on a separate core; contrast this to SMT, where two or more threads can share the same core by executing simultaneously.
AMD pitches Bulldozer as a middle ground between these two approaches, where two threads share a single front-end but have separate integer execution resources. After looking closely at Bulldozer, it's best described as a new form of SMT—AMD's "third way" description isn't inaccurate, but it's most useful to think of Bulldozer as an approach to SMT that builds on what has come before.
AMD pitches Bulldozer as a middle ground between these two approaches, where two threads share a single front-end but have separate integer execution resources. After looking closely at Bulldozer, it's best described as a new form of SMT—AMD's "third way" description isn't inaccurate, but it's most useful to think of Bulldozer as an approach to SMT that builds on what has come before.