Le 07/08/2012 01:45, Kenneth A. Lloyd a écrit : > But, isn't the returned matrix merely and adjacency matrix? Distance in > steps? This doesn't encode a weight, such as latency does it?
There could be different types of matrices. Right now, there's a single type called "latency" as defined by the ACPI SLIT specs (10 on the diagonal, >10 everywhere else, but we normalize things to get 1.0 on the diagonal). Brice > > Ken > > -----Original Message----- > From: hwloc-users-boun...@open-mpi.org > [mailto:hwloc-users-boun...@open-mpi.org] On Behalf Of Brice Goglin > Sent: Monday, August 06, 2012 4:47 PM > To: Wheeler, Kyle Bruce > Cc: <hwloc-us...@open-mpi.org> > Subject: Re: [hwloc-users] [EXTERNAL] Re: hwloc_get_latency() failures and > confusion > > Le 07/08/2012 00:36, Wheeler, Kyle Bruce a écrit : >> Ahhhh, that's key! The documentation currently says "Look at ancestor >> objects from the bottom to the top until one of them contains a >> distance matrix that matches the objects exactly", which suggests to >> me that it will traverse the object hierarchy looking for the >> NUMANodes *for* me. > Ahh, this one is exactly what's really confusing. There are two things here: > 1) the object that contains the distance matrix > 2) the object that are covered by the matrix > > When the matrix covers the entire machine (usual case), (1) is the root > object and (2) are NUMA nodes. > If you ever have a distance matrix between all cores of the first socket > (and not any other core in the machine), the first socket object would > contain a matrix with distance->relative_depth = depth(socket)-depth(core) > > So when you're looking for Core latencies, you check whether the ancestor > immediately above Core contain a matrix for Core distances, then its parent, > ... up to the root object. So it's about (1) moving up but (2) remains the > same type (but (2) gets wider when (1) goes up). > > Brice > > _______________________________________________ > hwloc-users mailing list > hwloc-us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users > > > _______________________________________________ > hwloc-users mailing list > hwloc-us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users
