On Tue, Dec 9, 2014 at 12:04 PM, Oleksandr Otenko <oleksandr.ote...@oracle.com> wrote: > On 26/11/2014 02:04, Hans Boehm wrote: >> >> To be concrete here, on Power, loads can normally be ordered by an address >> dependency or light-weight fence (lwsync). However, neither is enough to >> prevent the questionable outcome for IRIW, since it doesn't ensure that the >> stores in T1 and T2 will be made visible to other threads in a consistent >> order. That outcome can be prevented by using heavyweight fences (sync) >> instructions between the loads instead. > > > Why would they need fences between loads instead of syncing the order of > stores?
Well explained by http://www.cl.cam.ac.uk/~pes20/ppc-supplemental/test7.pdf
