Le 03/07/2011 23:55, Jiri Hladky a écrit : > Hi all, > > I have come across tests/hwloc_distances test and I believe that it > would be great to convert this into the utility > "hwloc-report-instances" published under utils/ directory. Please let > me know what you think about it. > > It would take the same input as hwloc-info (read topology from > different formats instead of discovering the topology on the local > machine), support both logical and physical indexes (-l and -p) switch.
By the way, lstopo shows distance information, but it does not change it depending on -l/-p. We may want to fix this. > I have used stream memory bandwidth benchmark > (http://www.cs.virginia.edu/stream/) in the past to produce the > similar output as tests/hwloc_distances. It was interesting to see > that numactl and kernel scheduler are both using number of hopes > instead of memory bandwidth. Actually, Linux only uses the number of hops on one specific MIPS architecture (SGI IP27 Origin 200/2000). In other cases, it uses the cpu-to-memory latency (usually reported by ACPI or so). > On some systems number of hops does not represent memory bandwidth. I > have reported this in BZ 655041 > > https://bugzilla.redhat.com/show_bug.cgi?id=655041 This bug is private unfortunately. > In any case I believe that hwloc-report-instances would be useful > utility. Please let me know your opinion. Agreed. There are still several things to improve regarding distances. Everything should be in https://svn.open-mpi.org/trac/hwloc/ticket/43 Brice
