[Bug 1827264] [NEW] ovs-vswitchd thread consuming 100% CPU

Jamon Camisso 1827264 at bugs.launchpad.net
Wed May 1 18:51:10 UTC 2019


Public bug reported:

I have an ovs-vswitchd process consuming 100% CPU in a very lightly used
Openstack Rocky cloud running on Bionic. The version in question is
openvswitch-switch 2.10.0-0ubuntu2~cloud0

ovs-vswitchd is running alongside various neutron processes
(lbaasv2-agent, metadata-agent, l3-agent, dhcp-agent, openvswitch-agent)
inside an LXC container on a physical host. There is a single neutron
router, and the entire environment including br-tun, br-ex, and br-int
traffic barely goes over 200KiB/s TX/RX combined.

The issue appears to have arisen on its own after the host was hard
rebooted. On restart ovs-vswitchd came up with high load and it has not
diminished since then.


The thread that is consuming CPU looks like this in ps and shows up with the name 'handler89':

UID          PID    SPID    PPID  C STIME TTY          TIME CMD
root        7267    7454       1 99 Apr23 ?        8-03:38:14 ovs-vswitchd unix:/var/run/openvswitch/db.sock -vconsole:emer -vsyslog:err -vfile:info --mlockall --no-chdir --log-file=/var/log/openvswitch/ovs-vswitchd.log --pidfile=/var/run/openvswitch/ovs-vswitchd.pid --detach


Logs in /var/log/openvswitch/ovs-vswitchd.log show ~14000 entries like this per day - roughly one per second:

2019-05-01T18:34:30.110Z|237220|poll_loop(handler89)|INFO|Dropped
1092844 log messages in last 6 seconds (most recently, 0 seconds ago)
due to excessive rate

2019-05-01T18:34:30.110Z|237221|poll_loop(handler89)|INFO|wakeup due to
[POLLIN] on fd 42 (unknown anon_inode:[eventpoll]) at ../lib/dpif-
netlink.c:2786 (99% CPU usage)


Logs in /var/log/neutron/neutron-openvswitch-agent.log show entries like
this, again one set per second for ~14000 per day:

2019-05-01 18:35:31.174 13621 DEBUG
neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-
7e354ade-55a3-46ba-adf4-db49a51e5218 - - - - -] Agent rpc_loop -
iteration:355070 started rpc_loop /usr/lib/python3/dist-
packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2086

2019-05-01 18:35:31.177 13621 DEBUG
neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch
[req-7e354ade-55a3-46ba-adf4-db49a51e5218 - - - - -] ofctl request
version=0x4,msg_type=0x12,msg_len=0x38,xid=0x81826d95,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=23,type=1)
result
[OFPFlowStatsReply(body=[OFPFlowStats(byte_count=0,cookie=13408676230369642694,duration_nsec=724000000,duration_sec=710697,flags=0,hard_timeout=0,idle_timeout=0,instructions=[],length=56,match=OFPMatch(oxm_fields={}),packet_count=0,priority=0,table_id=23)],flags=0,type=1)]
_send_msg /usr/lib/python3/dist-
packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:114

2019-05-01 18:35:31.179 13621 DEBUG
neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-
7e354ade-55a3-46ba-adf4-db49a51e5218 - - - - -] Agent rpc_loop -
iteration:355070 completed. Processed ports statistics: {'regular':
{'added': 0, 'updated': 0, 'removed': 0}}. Elapsed:0.005
loop_count_and_wait /usr/lib/python3/dist-
packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:1875


I'm not sure what else information to add here but am happy to gather more diagnostic data to try to pin this down. I did come across https://mail.openvswitch.org/pipermail/ovs-discuss/2018-October/047558.html which is the same version as mine and the symptoms appear to be the same. 


Below are various ovs-dpctl/ofctl show reports:


root at juju-df624b-4-lxd-10:~# ovs-dpctl show
system at ovs-system:
  lookups: hit:223561120 missed:5768546 lost:798
  flows: 131
  masks: hit:2284286371 total:15 hit/pkt:9.96
  port 0: ovs-system (internal)
  port 1: br-ex (internal)
  port 2: eth1
  port 3: gre_sys (gre: packet_type=ptap)
  port 4: br-tun (internal)
  port 5: br-int (internal)
  port 6: tapa062d6f1-40
  port 7: tapf90e3ab6-13
  port 8: tap45ba891c-4c


root at juju-df624b-4-lxd-10:~# ovs-ofctl show br-int
OFPT_FEATURES_REPLY (xid=0x2): dpid:00003643edb09542
n_tables:254, n_buffers:0
capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
 1(int-br-ex): addr:4a:b4:cc:dd:aa:ac
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 2(patch-tun): addr:7a:36:76:1f:47:6e
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 3(tapa062d6f1-40): addr:92:d4:6c:26:55:0a
     config:     0
     state:      0
     current:    10GB-FD COPPER
     speed: 10000 Mbps now, 0 Mbps max
 4(tapf90e3ab6-13): addr:9e:8b:4f:ae:8f:ba
     config:     0
     state:      0
     current:    10GB-FD COPPER
     speed: 10000 Mbps now, 0 Mbps max
 5(tap45ba891c-4c): addr:76:45:39:c8:d7:e0
     config:     0
     state:      0
     current:    10GB-FD COPPER
     speed: 10000 Mbps now, 0 Mbps max
 LOCAL(br-int): addr:36:43:ed:b0:95:42
     config:     PORT_DOWN
     state:      LINK_DOWN
     speed: 0 Mbps now, 0 Mbps max
OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0


root at juju-df624b-4-lxd-10:~# ovs-ofctl show br-tun
OFPT_FEATURES_REPLY (xid=0x2): dpid:000092c6c8f4a545
n_tables:254, n_buffers:0
capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
 1(patch-int): addr:02:1d:bc:ec:0c:3b
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 2(gre-0a30029b): addr:fe:09:61:11:92:8b
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 3(gre-0a3002a2): addr:a2:64:93:48:e2:82
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 4(gre-0a30029d): addr:12:b1:73:32:19:d4
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 5(gre-0a3002ce): addr:ca:10:51:f2:0f:05
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 6(gre-0a3002a1): addr:de:fe:95:33:d9:67
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 7(gre-0a30029e): addr:5a:fa:ce:15:7b:5c
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 8(gre-0a3002c3): addr:b6:87:66:09:fc:04
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 10(gre-0a3002a0): addr:ce:79:f2:bf:a8:94
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 14(gre-0a30029f): addr:b6:b0:84:7d:9f:aa
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 18(gre-0a30029c): addr:da:14:12:54:1c:ec
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 LOCAL(br-tun): addr:92:c6:c8:f4:a5:45
     config:     PORT_DOWN
     state:      LINK_DOWN
     speed: 0 Mbps now, 0 Mbps max
OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0


root at juju-df624b-4-lxd-10:~# ovs-ofctl show br-ex
OFPT_FEATURES_REPLY (xid=0x2): dpid:000000163e9a47a2
n_tables:254, n_buffers:0
capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
 1(eth1): addr:00:16:3e:9a:47:a2
     config:     0
     state:      0
     current:    10GB-FD COPPER
     speed: 10000 Mbps now, 0 Mbps max
 2(phy-br-ex): addr:ce:a8:6a:25:55:0e
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
 LOCAL(br-ex): addr:00:16:3e:9a:47:a2
     config:     0
     state:      0
     speed: 0 Mbps now, 0 Mbps max
OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0

** Affects: openvswitch (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1827264

Title:
  ovs-vswitchd thread consuming 100% CPU

Status in openvswitch package in Ubuntu:
  New

Bug description:
  I have an ovs-vswitchd process consuming 100% CPU in a very lightly
  used Openstack Rocky cloud running on Bionic. The version in question
  is openvswitch-switch 2.10.0-0ubuntu2~cloud0

  ovs-vswitchd is running alongside various neutron processes
  (lbaasv2-agent, metadata-agent, l3-agent, dhcp-agent, openvswitch-
  agent) inside an LXC container on a physical host. There is a single
  neutron router, and the entire environment including br-tun, br-ex,
  and br-int traffic barely goes over 200KiB/s TX/RX combined.

  The issue appears to have arisen on its own after the host was hard
  rebooted. On restart ovs-vswitchd came up with high load and it has
  not diminished since then.

  
  The thread that is consuming CPU looks like this in ps and shows up with the name 'handler89':

  UID          PID    SPID    PPID  C STIME TTY          TIME CMD
  root        7267    7454       1 99 Apr23 ?        8-03:38:14 ovs-vswitchd unix:/var/run/openvswitch/db.sock -vconsole:emer -vsyslog:err -vfile:info --mlockall --no-chdir --log-file=/var/log/openvswitch/ovs-vswitchd.log --pidfile=/var/run/openvswitch/ovs-vswitchd.pid --detach

  
  Logs in /var/log/openvswitch/ovs-vswitchd.log show ~14000 entries like this per day - roughly one per second:

  2019-05-01T18:34:30.110Z|237220|poll_loop(handler89)|INFO|Dropped
  1092844 log messages in last 6 seconds (most recently, 0 seconds ago)
  due to excessive rate

  2019-05-01T18:34:30.110Z|237221|poll_loop(handler89)|INFO|wakeup due
  to [POLLIN] on fd 42 (unknown anon_inode:[eventpoll]) at ../lib/dpif-
  netlink.c:2786 (99% CPU usage)


  Logs in /var/log/neutron/neutron-openvswitch-agent.log show entries
  like this, again one set per second for ~14000 per day:

  2019-05-01 18:35:31.174 13621 DEBUG
  neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-
  7e354ade-55a3-46ba-adf4-db49a51e5218 - - - - -] Agent rpc_loop -
  iteration:355070 started rpc_loop /usr/lib/python3/dist-
  packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2086

  2019-05-01 18:35:31.177 13621 DEBUG
  neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch
  [req-7e354ade-55a3-46ba-adf4-db49a51e5218 - - - - -] ofctl request
  version=0x4,msg_type=0x12,msg_len=0x38,xid=0x81826d95,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=23,type=1)
  result
  [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=0,cookie=13408676230369642694,duration_nsec=724000000,duration_sec=710697,flags=0,hard_timeout=0,idle_timeout=0,instructions=[],length=56,match=OFPMatch(oxm_fields={}),packet_count=0,priority=0,table_id=23)],flags=0,type=1)]
  _send_msg /usr/lib/python3/dist-
  packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:114

  2019-05-01 18:35:31.179 13621 DEBUG
  neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-
  7e354ade-55a3-46ba-adf4-db49a51e5218 - - - - -] Agent rpc_loop -
  iteration:355070 completed. Processed ports statistics: {'regular':
  {'added': 0, 'updated': 0, 'removed': 0}}. Elapsed:0.005
  loop_count_and_wait /usr/lib/python3/dist-
  packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:1875

  
  I'm not sure what else information to add here but am happy to gather more diagnostic data to try to pin this down. I did come across https://mail.openvswitch.org/pipermail/ovs-discuss/2018-October/047558.html which is the same version as mine and the symptoms appear to be the same. 

  
  Below are various ovs-dpctl/ofctl show reports:

  
  root at juju-df624b-4-lxd-10:~# ovs-dpctl show
  system at ovs-system:
    lookups: hit:223561120 missed:5768546 lost:798
    flows: 131
    masks: hit:2284286371 total:15 hit/pkt:9.96
    port 0: ovs-system (internal)
    port 1: br-ex (internal)
    port 2: eth1
    port 3: gre_sys (gre: packet_type=ptap)
    port 4: br-tun (internal)
    port 5: br-int (internal)
    port 6: tapa062d6f1-40
    port 7: tapf90e3ab6-13
    port 8: tap45ba891c-4c

  
  root at juju-df624b-4-lxd-10:~# ovs-ofctl show br-int
  OFPT_FEATURES_REPLY (xid=0x2): dpid:00003643edb09542
  n_tables:254, n_buffers:0
  capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
  actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
   1(int-br-ex): addr:4a:b4:cc:dd:aa:ac
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   2(patch-tun): addr:7a:36:76:1f:47:6e
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   3(tapa062d6f1-40): addr:92:d4:6c:26:55:0a
       config:     0
       state:      0
       current:    10GB-FD COPPER
       speed: 10000 Mbps now, 0 Mbps max
   4(tapf90e3ab6-13): addr:9e:8b:4f:ae:8f:ba
       config:     0
       state:      0
       current:    10GB-FD COPPER
       speed: 10000 Mbps now, 0 Mbps max
   5(tap45ba891c-4c): addr:76:45:39:c8:d7:e0
       config:     0
       state:      0
       current:    10GB-FD COPPER
       speed: 10000 Mbps now, 0 Mbps max
   LOCAL(br-int): addr:36:43:ed:b0:95:42
       config:     PORT_DOWN
       state:      LINK_DOWN
       speed: 0 Mbps now, 0 Mbps max
  OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0


  root at juju-df624b-4-lxd-10:~# ovs-ofctl show br-tun
  OFPT_FEATURES_REPLY (xid=0x2): dpid:000092c6c8f4a545
  n_tables:254, n_buffers:0
  capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
  actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
   1(patch-int): addr:02:1d:bc:ec:0c:3b
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   2(gre-0a30029b): addr:fe:09:61:11:92:8b
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   3(gre-0a3002a2): addr:a2:64:93:48:e2:82
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   4(gre-0a30029d): addr:12:b1:73:32:19:d4
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   5(gre-0a3002ce): addr:ca:10:51:f2:0f:05
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   6(gre-0a3002a1): addr:de:fe:95:33:d9:67
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   7(gre-0a30029e): addr:5a:fa:ce:15:7b:5c
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   8(gre-0a3002c3): addr:b6:87:66:09:fc:04
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   10(gre-0a3002a0): addr:ce:79:f2:bf:a8:94
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   14(gre-0a30029f): addr:b6:b0:84:7d:9f:aa
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   18(gre-0a30029c): addr:da:14:12:54:1c:ec
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   LOCAL(br-tun): addr:92:c6:c8:f4:a5:45
       config:     PORT_DOWN
       state:      LINK_DOWN
       speed: 0 Mbps now, 0 Mbps max
  OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0


  
  root at juju-df624b-4-lxd-10:~# ovs-ofctl show br-ex
  OFPT_FEATURES_REPLY (xid=0x2): dpid:000000163e9a47a2
  n_tables:254, n_buffers:0
  capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
  actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
   1(eth1): addr:00:16:3e:9a:47:a2
       config:     0
       state:      0
       current:    10GB-FD COPPER
       speed: 10000 Mbps now, 0 Mbps max
   2(phy-br-ex): addr:ce:a8:6a:25:55:0e
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
   LOCAL(br-ex): addr:00:16:3e:9a:47:a2
       config:     0
       state:      0
       speed: 0 Mbps now, 0 Mbps max
  OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0

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