4 ms·
total order on all accesses to a given location—loads from a single location can't be reordered w.r.t. each other either i don't remember seeing any wording re
by moonchild 2y ago
total order on all accesses to a given location—loads from a single location can't be reordered w.r.t. each other either
i don't remember seeing any wording relating to mixed-size accesses in the intel manual (not withstanding that the official models are ... ambiguous, to say the least, compared with what 3rd-party researchers have done)
- gpderetta 2y agoFor a total store order to be meaningful of course it implies that loads are also non visibly reordered. If a store falls in the forest but nobody is around to load it, was it really ordered :)
- moonchild 2y agoTbf you could say stores happen in order, and loads can happen out of order unless you fence. Personally I don't understand why we need such strong ordering constraints for weakly ordered reads—istm you can go much weaker and maintain sanity.
- gpderetta 2y ago> i don't remember seeing any wording relating to mixed-size accesses in the intel manual (not withstanding that the official models are ... ambiguous, to say the least, compared with what 3rd-party researchers have done) I was probably misremembering the details. The manual has to say this regarding #LOCK prefixed operations: "Software should access semaphores (shared memory used for signalling between multiple processors) using identical addresses and operand lengths. For example, if one processor accesses a semaphore using a word access, other processors should not access the semaphore using a byte access" which is already vague enough, but regarding general atomic load and stores I couldn't find anything.