Azure-docs: Please add information about how to test latency (RTT) when Accelerated Networking is enabled

[cbellee]

Using ping.exe to test latency is not valid in the case of Azure Accelerated Networking as it offloads TCP/UDP traffic to the FPGA chip, but not ICMP traffic. Instead, a tool such as qperf (that uses TCP for latency tests) should be used. qperf reports ~0.035 ms latency between Azure VMs with accelerated networking enabled, rather than 1-2ms when using ping.exe.
It would be good to include a section about network latency to avoid customers claiming latency isn't improved when this feature is enabled. Unfortunately, there's no tool (that I could find) to measure latency on a Windows machine, so this can only be tested on Linux machines currently. PSPing is able to perform TCP latency tests on Windows.

Disclaimer - I'm a Microsoft Azure FastTrack Engineer whose customer recently faced exactly this issue.

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Document Details

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• ID: 42423f75-6611-2ff6-135d-cd0a11bab7c2
• Version Independent ID: ae7c8bd5-2eb5-1c4d-af63-def403a4a574
• Content: Testing Azure VM network throughput
• Content Source: articles/virtual-network/virtual-network-bandwidth-testing.md
• Service: virtual-network
• GitHub Login: @steveesp
• Microsoft Alias: steveesp

[TravisCragg-MSFT]

@cbellee Thanks for the feedback! I have assigned the issue to the content author to evaluate and update as appropriate.

[bingosummer]

@TravisCragg-MSFT @steveesp
Hey, how it the issue going? I faced exactly this issue.
I use NTTTCP to test Bandwidth/Throughput. But I don't find any docs of testing latency on Linux VM with accelerated networking enabled. Please help!

Additionally, https://medium.com/@easonlai888/deep-dive-into-azure-virtual-machine-accelerated-networking-performance-79f379eb02bd shows that latency is not improved much. (CC: @cbellee) An official guidance will help to figure out whether the latency is improved or not.

[bingosummer]

I found PaPing, which is a Linux tool similar to PsPing.
CC: @cbellee

[steveesp]

I'm working on this. Thanks for your patience.

Here's a sample of what I have for Linux so far:

From bash command line (assumes git is installed)

git clone https://github.com/mellanox/sockperf
cd sockperf/
./autogen.sh
./configure --prefix=

make is slower, may take several minutes

make

make install is fast

sudo make install

Sample commands after install:

Server - assumes server's IP is 10.0.0.4:

sudo sockperf sr --tcp -i 10.0.0.4 -p 12345

Client - assumes server's IP is 10.0.0.4:

sockperf ping-pong -i 10.0.0.4 --tcp -m 1400 -t 11 -p 12345

[bingosummer]

BTW, autoconf is needed to run ./autogen.sh