"Boehm, Hans" wrote: [...]
In my mind, the main way in which sequential consistency differs from the cheaper acquire/release semantics that Alexander wants is that
Actually I want even more relaxed 'modes' model.
a) Dekker's algorithm (which by itself isn't that practically interesting), plus a number of real lock-free algorithms (which do matter) don't work.
b) In my mind, acquire/release is a far more difficult model to explain to non- experts than the model for C++ with only sequentially consistent atomics. You
Difficult model? I view it as job security for those who can understand. Consider also that http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html (x86 (including x86-64) part) "Load Seq_Cst: MOV (from memory) Store Seq Cst: (LOCK) XCHG // alternative: MOV (into memory),MFENCE" is an overkill for typical use cases (e.g. see recent "Double checked locking pattern article on aristeia" thread on comp.lang.c++.moderated), compared to http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html (x86 (including x86-64) part) "Load Acquire: MOV (from memory) Store Release: MOV (into memory)" regards, alexander.