System Details - AVD Test

This test collects various metrics pertaining to the CPU and memory usage of every processor supported by the chosen Session Host. The details of this test are as follows:

Target of the test : An Azure Virtual Desktop

Agent deploying the test : An internal agent.

Outputs of the test : One set of results for each processor on the chosen session host; an additional Summary descriptor will also appear for multi-processor desktops - this will report aggregate CPU and memory usage of the session host, across all processors.

Configurable parameters for the test
Parameters Description

Test Period

How often should the test be executed.

Host

The host for which the test is to be configured.

Port

The default port is NULL.

Show Steal Time

By default, this flag is set to No, indicating that this test does not report the Steal time measure. If you want the test to report that measure, then set the Show Steal Time flag to Yes.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

 

Measurements made by the test

Measurement Description Measurement Unit Interpretation

CPU utilization

This measurement indicates the percentage of time the chosen virtual desktop used this processor. For the Summary descriptor, this measure will report the aggregate CPU usage of the virtual desktop, across all its processors.

Percent

A high value could signify a CPU bottleneck. The CPU utilization may be high because a few processes are consuming a lot of CPU, or because there are too many processes contending for a limited resource. The detailed diagnosis of this test reveals the top-10 CPU-intensive processes on the virtual desktop.

System CPU utilization

Indicates the percentage of time this processor was used for system-level processing. For the Summary descriptor, this measure will report the percentage of time the virtual desktop used all its processors for system-level processing.

Percent

An unusually high value indicates a problem and may be due to too many system-level tasks executing simultaneously.

Run queue length

Indicates the instantaneous length of the queue in which threads are waiting for the processor cycle. This length does not include the threads that are currently being executed.

Number

A value consistently greater than 2 indicates that many processes could be simultaneously contending for the processor.

For multi-processor desktops, this measure is reported only for the Summary descriptor.

Blocked processes

Indicates the number of processes blocked for I/O, paging, etc.

Number

A high value could indicate an I/O problem on the guest (e.g., a slow disk).

For multi-processor desktops, this measure is reported only for the Summary descriptor.

Swap memory

Denotes the committed amount of virtual memory. This corresponds to the space reserved for virtual memory on disk paging file(s).

MB

An unusually high value for the swap usage can indicate a memory bottleneck. Check the memory utilization of individual processes to figure out the process(es) that has (have) maximum memory consumption and look to tune their memory usages and allocations accordingly.

For multi-processor desktops, this measure is reported only for the Summary descriptor.

Free memory

Indicates the free memory available.

MB

This measure typically indicates the amount of memory available for use by applications running on the target Azure virtual desktop.

For multi-processor desktops, this measure is reported only for the Summary descriptor.

Steal time

Indicates the percentage of time a virtual processor waits for a real CPU while the hypervisor is servicing another virtual processor.

Percent

This measure is applicable only for the Azure virtual desktops that are provisioned via VMware vSphere ESX.

A low value is desired for this measure.

A high value for this measure indicates that a particular virtual processor is waiting longer for real CPU resources. If this condition is left unattended, it can stall the tasks performed by the virtual processor and cause the overall performance of the virtual processor to deteriorate significantly and badly impact user-experience with the target virtual desktop.

The impact of stolen CPU always manifests in slowness but can have more profound effects on your infrastructure. Here are some examples:

  • Slower page load times
  • Slower database query times
  • Slower processing of reports
  • Increased queue size of asynchronous tasks because of an inability to process them quickly
  • Increased IaaS bill due to launching more servers to handle the same amount of load

To avoid such eventualities, administrators should either immediately terminate the AVD and launch a replacement or configure the AVD with more CPU.

Scan rate

Indicates the memory scan rate.

Pages/Sec

A high value is indicative of memory thrashing. Excessive thrashing can be detrimental to desktop performance.

For multi-processor desktops, this measure is reported only for the Summary descriptor.

The detailed diagnosis capability of the CPU utilization measure, if enabled, provides a listing of the top 10 CPU-consuming processes (see Figure 6). In the event of a CPU bottleneck, this information will enable users to identify the processes/applications consuming a high percentage of CPU time and the users who are running these applications. Administrators can then advise such users to stop the resource-hungry processes/applications, so as to release the CPU resource for more important processing purposes.

Figure 6 : Detailed diagnosis of the CPU utilization measure

Note:

While instantaneous spikes in CPU utilization are captured by the eG agents and displayed in the Measures page, the detailed diagnosis will not capture/display such instantaneous spikes. Instead, detailed diagnosis will display only a consistent increase in CPU utilization observed over a period of time.