the max tx queue lentgh value that is supported by qemu is 1024 seting it to 10000 will not help.
thisbug does not specify what netwrok backend is being used but i will assume you are using kernel ovs. on thing you could do is to enable multiqueue support. see: https://specs.openstack.org/openstack/nova-specs/specs/liberty/implemented/libvirt-virtiomq.html you could also try enabling hugepages and cpu pinning on the vms to enable better performance. if you have deployed with security groups enable you can also change to the openvswitch security group driver. this will disable hybridge plug and increase performance. assuming you are still seeing packet drops at this point then it indicates that you are exceeded the capasity of kernel ovs and need to consider other netwrok backends such as ovs-dpdk, sriov or vpp. in any case this is a support request not a bug so i am closing as invalid. ** Changed in: nova Status: New => Invalid -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1792763 Title: tap TX packet drops during high cpu load Status in OpenStack Compute (nova): Invalid Bug description: We are running openstack and hypervisor is qemu-kvm and noticed during peak 50% packet loss on tap interface of instance. I have found in google increase txqueue will solve this issue but in my case after increase to 10000 i am still seeing same issue. I have 32 core compute node and i didn't reserve any CPU core for hypervisor and i am running 2 vm instance with 15 vCPU core to each. OS: centos7.5 Kernel: 3.10.0-862.11.6.el7.x86_64 [root@ostack-compute-33 ~]# ifconfig tap5af7f525-5f | grep -i drop RX errors 0 dropped 0 overruns 0 frame 0 TX errors 0 dropped 2528788837 overruns 0 carrier 0 collisions 0 what else i should try? To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1792763/+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
