Issue and Impact seen:

Due to incorrect CPU topology generated by cadvisor (version 0.37), CNF Pod is allocated CPU 1 which is a hyperthread sibling of CPU 0 (CPU 0 hosts most of the OS and other components). This leads performance degradation of the Pod.
In earlier versions (k8s 1.18.9, cadvisor 0.35.0) , CPU allocation happened from CPU 2-14 , whereas in k8s version 1.19.3 , cadvisor version 0.37.0 , CPU allocation happens from CPU 1-13.

Issue detected version:

k8s version 1.19.3 , cadvisor version 0.37.0

Version where it works well:

k8s version 1.18.9, cadvisor version 0.35.0

Analysis done so far:

1. We see this issue on Singel NUMA , Multi Socket System

2. On version 0.35.0 , topology generated by cadvisor and fed to kubelet looks like below.
   Here there is a clear mapping of node/socket to cores/threads.

    "topology": [
      {
        "node_id": 0,
        "memory": 50628362240,
        "hugepages": [
          {
            "page_size": 1048576,
            "num_pages": 8
          }
        ],
        "cores": [
          {
            "core_id": 0,
            "thread_ids": [
              0,
              1
            ],
            "caches": [
              {
                "size": 4194304,
                "type": "Unified",
                "level": 2
              }
            ]
          }
        ],
        "caches": [
          {
            "size": 16777216,
            "type": "Unified",
            "level": 3
          }
        ]
      },
      {
        "node_id": 1,
        "memory": 0,
        "hugepages": null,
        "cores": [
          {
            "core_id": 0,
            "thread_ids": [
              2,
              3
            ],
            "caches": [
              {
                "size": 4194304,
                "type": "Unified",
                "level": 2
              }
            ]
          }
        ],
        "caches": [
          {
            "size": 16777216,
            "type": "Unified",
            "level": 3
          }
        ]
      },
    ... 
    ...
    ]
   

3. On version 0.37.0 , topology generated by cadvisor and fed to kubelet looks like below.
   Below there seems to be a mix up of socket and numa nodes.

   "topology": [
      {
        "node_id": 0,
        "memory": 50628362240,
        "hugepages": [
          {
            "page_size": 1048576,
            "num_pages": 8
          }
        ],
        "cores": [
          {
            "core_id": 0,
            "thread_ids": [
              0,
              1,
              10,
              11,
              12,
              13,
              14,
              15,
              16,
              17,
              18,
              19,
              2,
              20,
              21,
              22,
              23,
              24,
              25,
              26,
              27,
              28,
              29,
              3,
              30,
              31,
              4,
              5,
              6,
              7,
              8,
              9
            ],
            "caches": null,
            "socket_id": 4
          }
        ],
        "caches": null
      }
    ]
   

4. We suspect that following commit has introduced the bug.

    commit c5a9232a94846cdd9f2a80b3a969a7717e880e10
    Author: Katarzyna Kujawa <katarzyna.kujawa@intel.com>
    Date: Wed Mar 4 11:33:46 2020 +0100