Elements in an array are always stored in the expected [increasing] order, regardless of the endianess of the architecture. Moreover, due to the alignment rules, all members in a union will start at the same address.
It turns out there is no endianess conversion on the keys, so I suppose both peers have to somehow reach a consensus outside the PML. george. On Nov 8, 2011, at 08:57 , Nathan T. Hjelm wrote: > Sure, I can do that. My only concern is with sending between hosts of > different endianness. > > For example, if seg_key is 128 bits wide and the key32 is 64 bits then we > might run into this: > > Host 1: (big endian) > Set seg_key.key32[0] = 0x11111111 > > would result in seg_key: 0x00000000 0x00000000 0x11111111 0x00000000 > > Host 2: (little endian) > Set seg_key.key32[0] = 0x111111111 > > would result in seg_key: 0x11111111 0x00000000 0x00000000 0x00000000 > > If either host were to send the other one its seg_key and try to use the > key32 they would get garbage. I haven't tested this case yet but I can test > on a PPE of RR later today. > > -Nathan > > On Tue, 8 Nov 2011 08:26:04 -0500, Jeff Squyres <jsquy...@cisco.com> wrote: >> On Nov 7, 2011, at 9:48 PM, Nathan T. Hjelm wrote: >> >>> In retrospect I should have done a RFC for the 3rd change with a short >>> timeout. At the time (operating on little sleep) it seemed like the >> commits >>> would have minimal impact. Please let me know if the commits have any >>> negative impact. >> >> FWIW, I think I'd like to see a rollback of the increase of array sizes > in >> the seg_key union. They weren't necessary and might be slightly >> misleading. >> >> -- >> Jeff Squyres >> jsquy...@cisco.com >> For corporate legal information go to: >> http://www.cisco.com/web/about/doing_business/legal/cri/ >> >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel
