Tag Archives: Performance

Network Latency on Virtual Machine

Slight network latency may cause application problem  on sensitive virtual machines. Even the network responding time is just 3 or 7 ms. There is a way to improve the  stability of responding latency – Enable RSS on NIC.

Network traffic is handled by single CPU core when RSS is disabled. Enable it will distribute the workload to 4 cores by default. You can increase CPU for RSS by change registry.

To summarize the solution. Go to Device Manager -> NIC properties -> Advance -> Find RSS option  and enable it. You will see 2 – 3 network drops when applying it.

You can refer following articles for detail.

Poor network performance or high network latency on Windows virtual machines

Virtual Receive-side Scaling in Windows Server 2012 R2

Regarding increase CPU for RSS. Read following article to learn how to modify it.

Setting the Number of RSS Processors