Input Delay - AVD Test

One of the most difficult problems to diagnose by the administrators on virtual desktops is the poor performance of the applications installed. Traditionally, diagnosis was done by collecting CPU, memory, disk I/O and a few other metrics related to the applications. The data collected from traditional metrics were not sufficient to figure out the root cause of poor performance of the applications. This is because, they did not factor in issues such as user input delays that may be caused by the virtual desktop itself, and not by the applications running on it or by the network.

Typically, every user input (e.g. keyboard clicks and mouse clicks) sits in the input queue on the session host until such time it is picked up for processing by an application’s message queue. In the event of heavy load on the AVD therefore, user input delays may increase. This could be a sign that user experience is degrading to the point where administrators might want to add more hosts or increase the VM instance size. Therefore, it is necessary for administrators to measure the user input delays while the applications are being accessed. This can be easily measured using the Input Delay - AVD test!

With the help of this test, administrators can determine the maximum and average time taken by the applications to respond to the user input received by the chosen Session Host / Azure Virtual Desktop. This way, administrators can figure out if there is any time delay in responses from applications. In addition, these metrics help administrators to differentiate desktop issues from network/application issues.

Target of the test : Azure Virtual Desktop

Agent deploying the test : An internal agent

Outputs of the test : One set of results will be reported for the chosen Session Host / AVD

Configurable parameters for the test

Parameters	Description
Test period	This indicates how often should the test be executed.
Host	The host for which the test is to be configured.
Port	The default port is NULL.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Maximum input delay	Indicates the maximum amount of time lag detected between the user's input through any input device (e.g., mouse, keyboard) and the time at which the application responds to the input.	Seconds	Ideally, the values of these measures should be 0 or very low. To know exactly which user/application experiences the maximum input lag, you can refer to the detailed diagnosis revealed by these measures.
Average input delay	Indicates the average amount of time lag detected between the user's input through any input device (e.g., mouse, keyboard) and the time at which the application detected the input.	Seconds