Login Enterprise EUX score and VSImax

• Overview
• Why calculate the EUX score?
• Terms and related concepts
• How Login Enterprise gets data for EUX score
  • Determining EUX score
• EUX score
  • Calculating EUX score
  • Baseline and Steady state EUX scores
  • Representative score check
    • Changing EUX work folders
      • Why change the EUX work folder
      • How to change the EUX folder
• VSImax
  • Calculating VSImax
• Additional resources

Overview

The EUX score (End User Experience Score) is a rating that represents the performance of a Windows machine (virtual, physical, cloud, or on-premises) on a scale of 0 to 10 as experienced by the Virtual User. The EUX score can be calculated with any number of users (1 or more).

As you add more users to your VDI platform, expect your EUX score to drop. As more users demand a greater share of a VDI system's shared resources, performance and user experience decrease.

The EUX score was introduced in Login Enterprise version 4.11 and is updated to reflect the evolving hardware and software platforms that VDI infrastructure runs on.

Why calculate the EUX score?

Calculating an EUX (End User Experience) score can provide several benefits in various contexts, helping ensure that the products, systems, and services you provide deliver a positive and satisfying user experience. Here are some reasons why calculating an EUX score might be valuable:

• Quantitative assessment: An EUX score allows you to quantify the overall user experience of a product, system, or service. This can provide a clear and measurable indication of how well it meets the needs and expectations of its users.
• Benchmarking: By establishing a baseline EUX score, you can track changes over time or compare different versions or iterations of a product. This enables you to assess the impact of design changes or improvements on the user experience.
• Identifying pain points: An EUX score can highlight specific areas of the user experience that need attention or improvement. By identifying pain points or areas of dissatisfaction, you can prioritize efforts to address them and enhance the overall user experience.
• Informing design decisions: Quantitative data from EUX scores can provide valuable insights for making informed design decisions. It can help designers and developers understand which aspects of the user experience are most important to users and where to focus their efforts for maximum impact.
• Demonstrating value: For businesses and organizations, an EUX score can serve as a metric for demonstrating the value of investing in user experience improvements. A positive EUX score can indicate that the product or service is meeting user needs effectively, which can contribute to customer satisfaction, loyalty, and ultimately, business success.

Terms and related concepts

• EUX Score - an End User Experience score, i.e. a specific set of tools that produce measurements meant to closely approximate how a human would feel about using this machine. In other words, a score from 0 to 10. For more details, see EUX Score.
• EUX App - an Application or tool designed to measure or optimize the respective aspects of the system’s performance. For more details, see How Login Enterprise gets data for EUX score.
• EUX Timer - the EUX Applications collect a bunch of data, which are referred to as “timer results”. Each piece of data has a corresponding “timer” associated with it. The “timer” or the “action” is an EUX application with specific parameters. For more details, see Determining EUX Score.
• VSImax - the maximum number of concurrent active VDI sessions your hardware will support without compromising responsiveness. For more details, see VSImax.

How Login Enterprise gets data for EUX score

The EUX score is based on the data derived from the performance of the EUX apps on the machine. EUX apps are small Applications or tools designed to measure or optimize the respective aspects of the system’s performance. To calculate the EUX score, Login Enterprise uses 4 EUX apps:

Appspeed

This Application is like a specialized tool on your computer, that tracks its performance. When you launch it, it sets itself up, prepares its window, and gets ready to interact with you. It keeps track of how quickly it’s able to start up and be ready for your input. Because the Application itself is very small, we simulate the load by doing a bunch of CPU operations.

In the default EUX profile for the timer appspeed we launch this app with these arguments:

"Arguments": "folder=\"{myDocs}\" duration=10000 launchtimestamp={launchTimestamp}"

Compressionspeed

The purpose of this program is to test the performance of a multi-threaded file compression and decompression system. It measures how many blocks of data can be compressed and decompressed within a specified duration.

In the default EUX profile, we use these parameters:

Timer highcompression:

"Arguments": "folder=\"{myDocs}\" cachePct=25 writePct=35 duration=1000 threads=1 -high"

Timer fastcompression:

"Arguments": "folder=\"{myDocs}\" cachePct=25 writePct=35 duration=1000 threads=1"

Starting Login Enterprise 5.8, you can change the default EUX work folders via the Public API, and therefore change the location for the EUX apps to another location.

For more information, see Changing EUX work folders.

CPUspeed

The purpose of this program is to measure the performance of a CPU by running a set of computations in multiple threads for a specified duration. It creates a specified number of threads and then initiates a CPU workload test on each of them. Then it counts how many iterations of the workload were performed within the given duration.

In the default EUX profile for the timer cpuspeed we launch this app with these arguments:

"Arguments": "d=1000 t=4"

Diskspeed

The purpose of this Application is to measure the performance of disk I/O operations by running a set of read/write operations in multiple threads for a specified duration. It creates a specified number of threads and then initiates a disk I/O workload test on each of them. The program measures the number of I/O operations per second (IOPS) and various latency metrics.

In the default EUX profile, we use these parameters:

Timer diskmydocs:

"Arguments": "folder=\"{myDocs}\" blockSize=5m bufferSize=32K writeMask=0x0C0C cachePct=95 latencyPct=99 threads=1 duration=1000"

Timer diskappdata:

"Arguments": "folder=\"{appData}\" blockSize=50k bufferSize=4K writeMask=0x0C0C cachePct=95 latencyPct=99 threads=1 duration=1000"

Determining EUX score

The EUX score comprises various timers representing common user operations that closely correlate with human experience on the system. These actions enable Login Enterprise to measure Application responsiveness, keyboard input processing, CPU-intensive tasks, and storage I/O latency.

In addition, the EUX score for Load Testing also incorporates Application and session failures, resulting in a score reduction when these events occur.

For more information on the 2023 EUX timers, see the following table.

EUX score

Calculating EUX score

The EUX score calculation is the same whether it’s the minute-by-minute score or the total EUX score. It is done in three steps. For the minute-by-minute calculation, we only take the results in the 1-minute “bucket“; for the total EUX, we take into account the results from the whole Test.

• Multiply every timer score by a hard-coded weight parameter and sum all of those results together
• Sum all of the actual weight parameters together
• Divide the weighted score sum from the sum of all weights.

In the end, the EUX score is the weighted average of all the EUX timer scores. A weighted average is an average where each value has a specific weight or frequency assigned to it. This means that some values contribute more to the average than others.

We also do not calculate the EUX score if any required timers (with a weight higher than zero) are missing. This usually only affects the beginning of the test, and even one value per timer is enough. We do not have any checks to ensure the amount of values that should be available.

Baseline and Steady state EUX scores

The Baseline and Steady state EUX scores provide additional dimensions to the experience your Virtual Users are having. The standard EUX score provides a single score for the duration of the entire Test, including the login period and the Application interaction period during the test run. As more users are steadily added to the system being tested, naturally the system will work harder and start to impact the user experience. The Steady state and Baseline EUX scores show us what the user experience is like during specific periods of the Test run.

Baseline EUX score

The Baseline EUX score represents the best possible performance of the system and is the average EUX score of the best 5 minutes of the Test. This score indicates how the system performs when it is not under stress. Typically, the Baseline score is captured at the beginning of the Test before the system is fully loaded.

Steady state EUX score

The Steady state period represents the time after all users have logged in (login storm) and the system starts to normalize. The Steady State EUX score is the average of the EUX scores captured 5 minutes after all sessions are logged in, until the end of the Test.

Representative score check

The total score is checked to see if it is representative. This is determined by checking if all timers have at least 10 samples. If the total score is representative, it is used as the final score. Otherwise, the final score is set to 0.

Application failures

Currently, the Application failures, being the workload scripts or EUX Application (timer) failures do not have an impact on the EUX score. Workload Application failures had an impact on the EUX2021 implementation, and it was a percentage-based penalty, 80% success rate was translated to the 20% reduction in the EUX score.

Changing EUX work folders

Why change the EUX work folder

To ensure optimal performance and accuracy of EUX calculations, it may be necessary to configure the location of the EUX work folder. This helps avoid potential issues associated with using folders that are mapped to network drives or other locations unsuitable for EUX I/O operations. By selecting an appropriate location, sensitive directories are avoided, resulting in more realistic EUX and Max scores.

You can customize the properties of the EUX work folder when updating a test configuration for both the Load and Continuous tests.

Starting from Login Enterprise 5.8, you can update 3 EUX folders through the Public API. Note the following folders are default:

• EUX Folder location
  • "euxFolderPath": "%USERPROFILE%\AppData\Local\Temp"
• EUX Appdata location
  • "appDataFolderPath": "%USERPROFILE%\AppData\Local\eux2023"
• My Documents location
  • "myDocumentsFolderPath": "%USERPROFILE%\Documents\eux2023"

How to change the EUX folder

To change the EUX folder to a custom EUX folder in the Public API, you need to use a corresponding endpoint. To do this:

1. In your Login Enterprise, open the Swagger UI console with the v7.0-preview API. To learn how to do this, see Accessing Public API/Swagger UI (When done, go back to this page for further instructions).

2. In the Open API Specification, find Test, and click GET /v7-preview/tests{testId} Get test by id.

3. Perform a GET operation on the Test to get the current configuration of the Test. Make sure to leave “Include” set to "none”.

4. Copy the entire body from the GET output into your PUT request and modify your desired values.

5. Click Execute. The response status code should show 200:

6. Finally, go back to GET and verify the changes:

When using custom EUX folders, it's essential to consider several cautions to ensure the security, integrity, and efficiency of the process:

• During creation, EUX work folders cannot be set; any properties configured will default to null.
• For successful operation, custom EUX work folders must grant full access to virtual user accounts. By default, the first session creates the EUX folder and files, restricting access to subsequent sessions, and causing EUX errors. Access permissions should be carefully managed to avoid these issues.

VSImax

VSImax defines the maximum number of concurrent users that can operate with an acceptable EUX score. If a system exceeds the number of sessions reported in the VSImax score, the End User Experience is expected to progressively degrade.

Calculating VSImax

VSImax is triggered when the EUX score dips below a certain value. By default, this value is defined to be an EUX score of 5.5 VSImax will be the last number of sessions currently logged in before the EUX average dropped below 5.5.

For instance, in this chart, EUX dropped below 5.5 after 12 sessions were logged in, so VSImax was set to 12:

There are two possible criteria for triggering VSImax:

• An absolute value that indicates at which point the experience starts to degrade (the default).
• A relative value based on the performance of the system when it is running optimally.

By default, we use the “absolute value” option, set to 5.5. However, it’s possible to configure Login Enterprise to choose VSImax based on a relative drop instead. For instance, we can trigger VSImax when the average EUX score drops to 85% of the baseline. For more information, see Baseline and Steady State EUX scores.

It is not normally necessary to change how VSImax is calculated. However, if your VSImax scores do not reflect your users' experiences, or if your EUX scores are consistently above or below 5.5, it’s possible to change the trigger threshold. For more information about how to change the VSImax calculation, contact Support at support@loginvsi.com.

Additional resources

• For troubleshooting EUX score and VSImax, see EUX score and VSImax troubleshooting.
• To learn how to export the EUX raw data, see Exporting EUX data.

For any questions or concerns related to EUX score or VSImax, feel free to reach out to our support team at support@loginvsi.com.