On Mon, Dec 19, 2016 at 4:18 AM, Alex Khripin <akhri...@alum.mit.edu> wrote: > Hi Dmitry, > First -- relacy is great, thank you for providing this tool and all the > other stuff on 1024cores. > > Second -- I ran into a hiccup. This might be something I don't properly > understand in the C++11 spec, but, relacy does not seem to support > > compare_exchange_strong(foo, bar, rl::mo_release, rl::mo_acquire) > > When RL_VERIFY is enabled, this triggers an error: > RELACY INTERNAL ASSERT FAILED: 'collecting_history()' at > ../../relacy/context_base_impl.hpp:60 (exec_log) > > Reading the code, it looks like if the normal memory model is release, then > the only failure model supported is relaxed. > > atomic.hpp line 338 in the big compare_exchange switch statement > > I know the specification prohibits the failure memory order from being > stronger than the success order -- I am not 100% sure, but I think the above > ordering (success = release, failure = acquire) does satisfy that > requirement. > > This is mostly academic -- I can set the success order to acq_rel -- but it > did take me some time to figure out what was going on. I am curious now if I > am completely off base, or if this is a missing combination.
+relacy mailing list Hi Alex, The stronger requirement is somewhat vague as there are unordered memory orders. But I always read it as relacy implements it -- failure order must be equal or weaker. Do you have any indication that release/acquire is an allowed combination? -- --- You received this message because you are subscribed to the Google Groups "Scalable Synchronization Algorithms" group. To unsubscribe from this group and stop receiving emails from it, send an email to lock-free+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/lock-free/CAEeQi3uMEJpFPrVLLW-A9fuMiAyvq7CQJxJ-0_iT4AhsTgh_Zg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
