19. VNIC characteristics
Hyper-V Vmware Xen KVM
vmxnet3 netfront virtio-net
MTU 1500 9000 65521 65535
Checksum Y Y Y
offload
Segmentation Y Y Y
offload
NAPI Y Y Y
LRO Y
VLAN Y
Multiqueue Y ? ?
20. Guest to Guest Throughput
TSO
Tx csum
No offload
0 1000 2000 3000 4000 5000
Megabits/sec
21. VM to VM performance
2000
Thorouhput (10^6 bits/sec)
0
100 1000 10000 100000
MTU (bytes)
27. Future work
Virtio-net optimization Michael S. Tsirkin
Multiqueue Krishna Kumar
KVM ↔ QEMU
Zero copy Shirley Ma
Skb lifetime
Security
Batching Rusty Russell
Bufferbloat
28. How to help
Administrator →Tuning and Sizing
Tester →Measure and Test
Developer →Multiqueue and
Offload
Notas do Editor
Performance is a complex topic, and hard to measure. The blind man who feels a leg says the elephant is like a pillar; the one who feels the tail says the elephant is like a rope; the one who feels the trunk says the elephant is like a tree branch; the one who feels the ear says the elephant is like a hand fan; the one who feels the belly says the elephant is like a wall; and the one who feels the tusk says the elephant is like a solid pipe. A wise man explains to them: "All of you are right. The reason every one of you is telling it differently is because each one of you touched the different part of the elephant. So, actually the elephant has all the features you mentioned."
I use Virt net every day but always felt uncomfortable that performance is being lost. Rules of thumb, today, on my hardware
In honor of Australia day wanted to graph it upside down!! Not a benchmark * different hardware * not precise * not allowed by License agreements