Free License Trade OutIT professionals know that troubleshooting session slowness in Citrix XenApp, XenDesktop, and VMware Horizon is very challenging under any circumstances.  The number of factors, from the user endpoint, to network issues, server resources, application performance, and latency demand broad and deep visibility to track these elusive issues.

One global insurance provider challenged Goliath to find the root cause of random but persistent session slowness issues reported by their Citrix XenDesktop and VMware Horizon international users.  The company had recently migrated workloads from one data center in the Caribbean to another in the northern United States.  After the migration, some users reported overall session performance issues manifesting as delays interacting with sessions, session disconnects, and blue screen session crashes.

The troubleshooting team loaded Goliath Performance Monitor (GPM) and started with isolating sessions from users who experienced and reported issues.  Since GPM maintains full historic session data without rollup or aggregation, the team could analyze and troubleshoot specific metrics from impacted sessions, even though they were in the past.

The first user investigated was connecting from the UK.  With Goliath Performance Monitor, the team could immediately see overall high CPU load for this user in the Virtual Machine Metrics Screen.

Next, GPM showed higher than normal disk latency:

After that, GPM confirmed the increased CPU Utilization was driven by Citrix Graphics and Desktop Window Manager:

Taken altogether, this data indicated that the issues with this machine were graphics-related.  One area often causing this behavior is Microsoft Office, which needs to be specially tweaked and tuned for use in a Citrix XenApp and XenDesktop environment.  This article by Marius Sanbu, CTP discusses the proper settings and process:

For Windows, there are similar settings to ensure that animations, transparencies, and similar features are disabled over VDI to improve performance.

There is also a possibility that a specific application within the session beyond the above referenced is causing the issue. This occurs, (for example) with applications coded utilizing the Microsoft Windows Presentation Foundation toolset. Applications utilizing WPF heavily utilize Direct3D and hardware acceleration and have been known to cause issues similar to those reported here.

A second user session was investigated and provided new metrics that supported the idea that these issues were graphics-related.  First, GPM showed a sustained period of high Frames Per Second (FPS).

In this case, the user had sustained video traffic at nearly 25 FPS for over an hour within their Citrix session.  In most environments this is abnormal behavior and can contribute to slow session performance.

A third user account was reviewed with a non-vGPU enabled session, and overall performance in this case was very smooth.  The high CPU, graphics-related issues, or other performance problems were not present in this session.

The detailed metrics available in the Goliath Performance Monitor led the troubleshooting team to conclude there was an issue specifically related to either the NVIDIA vGPU or applications running within NVIDIA vGPU-enabled sessions.  The team adjusted the NVIDIA vGPU profile configuration for the affected users and Goliath Performance Monitor confirmed this resolved the issue.

This is one example of how our customers use Goliath Technologies to anticipate, troubleshoot, and prevent end user experience issues.  To see how Goliath Performance Monitor can give you the visibility required to troubleshoot issues in your Citrix XenApp, Citrix XenDesktop, or VMware Horizon environments, click the image below and sign up for a personalized demo.

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