Open MPI logo

Hardware Locality Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [hwloc-devel] hwloc_distances as utility?
From: Jiri Hladky (hladky.jiri_at_[hidden])
Date: 2011-07-05 16:04:45

Hi Brice,

> By the way, lstopo shows distance information, but it does not change it
> depending on -l/-p. We may want to fix this.

Thanks for the hint, I din't know it.

> 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).

Well, this is interesting. numactl --hardware shows the number of hops,
regarding to the information from that private BZ. Where does hwloc takes
the distance information? Is it stored with


script? If yes, could me send me the output of hwloc-gather-topology for
some NUMA box? I don't have access to any NUMA running a recent version of

> > On some systems number of hops does not represent memory bandwidth. I
> > have reported this in BZ 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.

OK, I will try to implement it as time permits.