Network Performance Analysis of C3 instances using Iperf tool

In our previous posts, we talked about CPU and disk I/O performance of c3 instances. In this post, we will focus on network performance. Amazon offers an Enhanced Networking feature for ‘c3’ instances running with hvm AMIs with the right drivers. In all our tests, we have used an HVM AMI with enhanced networking enabled.

To assess network performance, we ran three types of benchmark tests:

  • Iperf test → to measure bandwidth. You can get more details about Iperf tool here.
  • Sockperf ping-pong test → to measure network latency on tcp. Sockperf is a network performance measuring tool. You can get more details on sockperf here. In ping-pong mode, sockperf can be used to measure network latency.
  • Ping test → to measure network latency using ICMP ping.

We also compared the network performance between two identical instances within a VPC, as well as in a classic EC2 network. In all our tests, the systems under test (server and client) belong to the same placement group.

In the following table are the results of network performance.

c3 instances iperf

The results are pretty consistent for all the instances, except for c3.8xlarge in EC2-classic network. The standard deviation here is relatively higher.

c3 instances iperf 1

Here is the network performance per the hourly rent in dollars.

c3 instances iperf 2

We can see that c3.large and c3.8xlarge provide almost equivalent performance.

Network Latency results:


 

As mentioned earlier, we measured latency with two tools. Here are the results of latency when measured using the sockperf ping-pong tool.

c3 instances iperf 3

c3 instances iperf 4

Although we see slight differences in the latencies between different instances, considering the standard deviation, we can see that c3.xlarge and c3.2xlarge offer almost the same network latency. It is the same with c3.4xlarge and c3.8xlarge, as well.

Here is the graph for ping latency. We used standard 64-byte messages for the ping tests.

c3 instances iperf 5

As you can see from both graphs , there is a considerable difference between the Ec2 -classic network and VPC when it comes to network latency.

It should also be noted that we see an improved network latency in a VPC only when the enhanced networking feature is used. We also ran a few tests to get a flavor for the network performance when the enhanced networking is not used. As a result, we found that when the enhanced networking is not used, there is not much difference in network latency between a VPC network and EC2-classic network.

You can learn more about our benchmarking exercises by checking our other benchmarking posts here

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May 06, 2014 / Compute

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