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[Stephen Finucane <sfinucan@xxxxxxxxxx>]

Having discussed this since, it's clear that this isn't a bug but a
design decision. nova allows scheduling PCI devices on hosts without an
exposed NUMA topology as this satisfies the majority of use cases. It
would be possible to make this behavior configurable, but this is a
feature request - not a bug - and would require a spec [1].

[1] https://review.openstack.org/#/c/361140/

** Changed in: nova
       Status: In Progress => Invalid

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https://bugs.launchpad.net/bugs/1551504

Title:
  I/O (PCIe) Based NUMA Scheduling  can't really achieve pci numa
  binding in some cases.

Status in OpenStack Compute (nova):
  Invalid

Bug description:
  1. version
  kilo 2015.1.0, liberty

  this bug is base on BP:
  https://blueprints.launchpad.net/nova/+spec/input-output-based-numa-scheduling

  In the current implementation scheme:

  /nova/pci/stats.py
  ################################################################################
   def _filter_pools_for_numa_cells(pools, numa_cells):
          # Some systems don't report numa node info for pci devices, in
          # that case None is reported in pci_device.numa_node, by adding None
          # to numa_cells we allow assigning those devices to instances with
          # numa topology
          numa_cells = [None] + [cell.id for cell in numa_cells]
  #################################################################################

  If some compute nodes don't report numa node info for pci devices.
  Then these pci devices will be regarded as "belong to all numa node" to deal with by default.

  This can lead to a problem:
  Pci devices is not on the numa node which CPU\MEM on.
  In this way, the real purpose of I/O (PCIe) Based NUMA Scheduling is not reached.
  More serious is that the user will be wrong thought pci devices is on the numa node that CPU\MEM on.

  The truth is, there are still many systems don't report numa node info for pci devices.
  So, i think this bug need fixed.

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