Network Adapter PerformanceKb

[mygeeknc]

I have two 2008 R2 boxes, one of which is an RDS server and the other just a console essentially. I'm getting some weird performance issues on the RDS server with high interrupts which through some research seems to be coming from the virtio driver. As a test using iperf, I switched out the e1000 NIC for a virtio NIC on the secondary 2k8 server with interesting results.

The original test I did between the RDS (virtio) and the 2k8R2 (e1000) yielded 167 Mbits/sec. Each VM is on a separate VM host with a gigabit switch between them.

I then did a test between the RDS (virtio) server and the vm host which yielded 652 Mbits/sec.

I then swapped out the the 2k8R2 (e1000) for a virtio NIC and reran my tests. My tests between the RDS and 2k8R2 are seeing ~185Kbits/sec. Yea, Kbits!

Why in the world would the performance be SO bad for two servers with virtio NICs?

 

[dietmar]

Why in the world would the performance be SO bad for two servers with virtio NICs?

Bug in iperf benchmark tool?

 

[mygeeknc]

Is there a way to confirm that?

 

[mygeeknc]

Also, as a comparison. I tested this from a 2012 R2 server (virtio) to the RDS (virtio) and I saw ~428 Mbits/sec. Both are using the latest (1.81) virtio drivers from 4/29/2014.

 

[spirit]

AFAIK, inbound bandwith is slower than outbounf bandwidth currently,

also win2012r2 is faster in outbound (3-5gbit/s out win2012r2 vs 1gbit/s out win2008r2).

I can't reach more than 1gbit/s inbound with win2008 or windows 2012.

I have benched this with netperf because iperf was indeed too slow.
https://i18n-zh.googlecode.com/files/NetPerf-2.4.5-w32.zip


for inbound, I known that optimisations are coming for next virtio releases, using multiqueue.

The main performance problem with windows, is cpu usage of the driver which is higher than on linux.

Check the [vhost-xxx] process on the host (currently single threaded), if it's running at 100%, that mean it's cpu limited.
Coming multiqueue support will help to have multithreaded vhost process.

That's also mean that currently, cpu frequency is also important (intel will be faster than amd)