Public bug reported: The excessive calls to 'ip link show' can consume significant amounts of CPU cycles on every scan_devices iteration on densely packed SR-IOV systems.
Snip from https://bugs.launchpad.net/mos/+bug/1653131 : On a node with SR-IOV interfaces neutron-sriov-agent seems to call 'ip link show' every 2 second for each interface. This leads to CPU utilization up to 60+% (I've seen 32% for neutron-rootwrap and 32% for neutron-sriov-nic-agent) Since output of `ip link show' is the same for all interfaces, it is enough to call it only once per 2 sec interval root@node-7:~# grep '15:10:' /var/log/neutron/neutron-sriov-agent.log | grep "'ip', 'link', 'show'" | wc -l 5783 ** Affects: neutron Importance: High Assignee: Kevin Benton (kevinbenton) Status: In Progress ** Changed in: neutron Assignee: (unassigned) => Kevin Benton (kevinbenton) ** Changed in: neutron Importance: Undecided => High -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. https://bugs.launchpad.net/bugs/1653880 Title: sr-iov device scanning takes significant time Status in neutron: In Progress Bug description: The excessive calls to 'ip link show' can consume significant amounts of CPU cycles on every scan_devices iteration on densely packed SR-IOV systems. Snip from https://bugs.launchpad.net/mos/+bug/1653131 : On a node with SR-IOV interfaces neutron-sriov-agent seems to call 'ip link show' every 2 second for each interface. This leads to CPU utilization up to 60+% (I've seen 32% for neutron-rootwrap and 32% for neutron-sriov-nic-agent) Since output of `ip link show' is the same for all interfaces, it is enough to call it only once per 2 sec interval root@node-7:~# grep '15:10:' /var/log/neutron/neutron-sriov-agent.log | grep "'ip', 'link', 'show'" | wc -l 5783 To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1653880/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
