Hello, The doc says "get the last physical CPU where the current process or thread ran". As usual, there's no well-defined portable way to identify those things. On AMD, it's a core. On Intel, it's a hyperthread, and could also be a core if HT is disabled. On other archs/systems, it may be called "logical processor" or "execution unit" instead. We try to explain that at the end of the glossary http://www.open-mpi.org/projects/hwloc/doc/v1.7.2/a00001.php but we can't repeat that everywhere.
the actually returns a cpuset, so it doesn't actually return any object, but you can convert the cpuset into what you want. It sets a single bit in that cpuset (once per thread if you look at an entire processor), so that corresponds to a single HT thread on Intel, but that's also a single core on Intel without HT. Brice Le 05/10/2013 02:45, Vlad a écrit : > Greetings, > > I've been a user for a while and have just noticed an area where the > API documentation is either unclear or the version I am using (1.7 on Fedora > 17) returns a wrong topology object type. Specifically, I took the "physical > CPU" wording to mean HWLOC_OBJ_CORE but on a machine that has hyperthreading > enabled the above method appears to return HWLOC_OBJ_PU). > > Most likely, all is well (returning the smallest processing element of > hardware kind of makes more sense) and I'd misunderstood the API all along (I > work mostly on machines with HT disabled), but it would be useful to confirm. > > Thanks in advance, > Vlad > > > _______________________________________________ > hwloc-users mailing list > hwloc-us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users
