Hi Brice,
Setting HWLOC_ALLOW=all made hwloc usable on my oddly-configured VPS:
./lstopo
Machine (4096MB total) + Package L#0
NUMANode L#0 (P#0 4096MB)
L3 L#0 (20MB)
L2 L#0 (256KB) + L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 + PU L#0 (P#0)
L2 L#1 (256KB) + L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 + PU L#1 (P#1)
L2 L#2 (256KB) + L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2 + PU L#2 (P#2)
L2 L#3 (256KB) + L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3 + PU L#3 (P#3)
As I mentioned, I use this system only for testing builds, so this
"workaround" should enable me to build a working OpenMPI that I can
use as a component in applications.
Thank you!
Max
---
On Wed, Aug 02, 2023 at 03:38:46PM +0200, Brice Goglin wrote:
> The cgroup information under /sys/fs/cgroup/ should be fixed. cpuset.cpus
> should contain 0-3 and cpuset.mems should contain 0. In the meantime, hwloc
> may ignore this cgroup info if you set HWLOC_ALLOW=all in the environment.
>
> The x86 CPUID information is also wrong on this machine. All 4 cores report
> the same "APIC id" (sort of hardware core ID), I guess all your 4 cores are
> virtualized over a single hardware core and the hypervisor doesn't care
> about emulating topology information correctly.
>
> Brice
>
>
>
> Le 02/08/2023 à 15:23, Max R. Dechantsreiter a écrit :
> > Hi Brice,
> >
> > Well, the VPS gives me a 4-core slice of an Intel(R) Xeon(R)
> > CPU E5-2620 node, which is Sandy Bridge EP, with 6 physical
> > cores, so probably 12 cores on the node. The numbering does
> > seem wacky: it seems to describe a node with 2 8-core CPUs.
> >
> > This is the VPS on which I host my Web site; I use its shell
> > account for sundry testing, mostly of build procedures.
> >
> > Is there anything I could do to get hwloc to work?
> >
> > Regards,
> >
> > Max
> > ---
> >
> >
> > On Wed, Aug 02, 2023 at 03:12:27PM +0200, Brice Goglin wrote:
> > > Hello
> > >
> > > There's something wrong in this machine. It exposes 4 cores (number 0 to
> > > 3)
> > > and no NUMA node, but says the only allowed resources are cores 8-15,24-31
> > > and NUMA node 1. That's why hwloc says the topology is empty (running
> > > lstopo
> > > --disallowed shows NUMA 0 and cores 0-3 in red, which means they aren't
> > > allowed). How did this get configured so badly?
> > >
> > > Brice
> > >
> > >
> > >
> > > Le 02/08/2023 à 14:54, Max R. Dechantsreiter a écrit :
> > > > Hello,
> > > >
> > > > On my VPS I tested my build of hwloc-2.9.2 by running lstopo:
> > > >
> > > > ./lstopo
> > > > hwloc: Topology became empty, aborting!
> > > > Segmentation fault
> > > >
> > > > On a GCP n1-standard-2 a similar build (GCC 12.2 vs. 13.2) seemed to
> > > > work:
> > > >
> > > > ./lstopo
> > > > hwloc/nvml: Failed to initialize with nvmlInit(): Driver Not Loaded
> > > > Machine (7430MB total)
> > > > Package L#0
> > > > NUMANode L#0 (P#0 7430MB)
> > > > L3 L#0 (45MB) + L2 L#0 (256KB) + L1d L#0 (32KB) + L1i L#0 (32KB)
> > > > + Core L#0
> > > > PU L#0 (P#0)
> > > > PU L#1 (P#1)
> > > > HostBridge
> > > > PCI 00:03.0 (Other)
> > > > Block(Disk) "sda"
> > > > PCI 00:04.0 (Ethernet)
> > > > Net "ens4"
> > > > PCI 00:05.0 (Other)
> > > >
> > > > (from which I conclude my build procedure is correct).
> > > >
> > > > At the suggestion of Brice Goglin (in response to my post of the same
> > > > issue to Open MPI Users), I rebuilt with '--enable-debug' and ran
> > > > lstopo;
> > > > then I also ran
> > > >
> > > > hwloc-gather-topology hwloc-gather-topology
> > > >
> > > > The resulting lstopo.tar.gz and hwloc-gather-topology.tar.gz are
> > > > attached,
> > > > as I was unable to recognize the underlying problem, although I believe
> > > > it
> > > > could be a system issue, for my builds of OpenMPI on the VPS used to
> > > > work
> > > > before a new OS image was installed.
> > > >
> > > > Max
> >
> >
_______________________________________________
hwloc-users mailing list
hwloc-users@lists.open-mpi.org
https://lists.open-mpi.org/mailman/listinfo/hwloc-users
