Hi Alex,
I'm sending you some benchmarks and information about VSOCK CCing qemu-devel
and linux-netdev (maybe this info could be useful for others :))
One of the VSOCK advantages is the simple configuration: you don't need to set
up IP addresses for guest/host, and it can be used with the standard POSIX
socket API. [1]
I'm currently working on it, so the "optimized" values are still work in
progress and I'll send the patches upstream (Linux) as soon as possible.
(I hope in 1 or 2 weeks)
Optimizations:
+ reducing the number of credit update packets
- RX side sent, on every packet received, an empty packet only to inform the
TX side about the space in the RX buffer.
+ increase RX buffers size to 64 KB (from 4 KB)
+ merge packets to fill RX buffers
As benchmark tool I used iperf3 [2] modified with VSOCK support:
host -> guest [Gbps] guest -> host [Gbps]
pkt_size before opt. optimized before opt. optimized
1K 0.5 1.6 1.4 1.4
2K 1.1 3.1 2.3 2.5
4K 2.0 5.6 4.2 4.4
8K 3.2 10.2 7.2 7.5
16K 6.4 14.2 9.4 11.3
32K 9.8 18.9 9.2 17.8
64K 13.8 22.9 8.8 25.0
128K 17.6 24.5 7.7 25.7
256K 19.0 24.8 8.1 25.6
512K 20.8 25.1 8.1 25.4
How to reproduce:
host$ modprobe vhost_vsock
host$ qemu-system-x86_64 ... -device vhost-vsock-pci,guest-cid=3
# Note: Guest CID should be >= 3
# (0, 1 are reserved and 2 identify the host)
guest$ iperf3 --vsock -s
host$ iperf3 --vsock -c 3 -l ${pkt_size} # host -> guest
host$ iperf3 --vsock -c 3 -l ${pkt_size} -R # guest -> host
If you want, I can do a similar benchmark (with iperf3) using a networking
card (do you have a specific configuration?).
Let me know if you need more details!
Thanks,
Stefano
[1] https://wiki.qemu.org/Features/VirtioVsock
[2] https://github.com/stefano-garzarella/iperf/
