(Forked from issue #11)

One operation that never made it into ES was an instruction to relax in a spinloop (ie, the PAUSE instruction in x86, IIRC). It was in the very earliest drafts of the spec but I think that, more than anything, it was considered very low-level for ES and something that would create controversy. (I experimented with a related idea, a micro-wait primitive with a back-off scheme, and I called that "pause" too, but it's not what I'm talking about here.)

I know that PAUSE is important for performance on x86. I don't know if ARM has anything similar in eg its event instructions (WFE). I don't know if it's a good idea to push this through for the MVP since we won't be able to remove it again if it turns out to be the wrong thing.