To ensure the optimal combination of end-user experience (EUE) and cost-per-user, we conducted performance analysis and characterization (PAAC) testing on this solution using the Login VSI load-generation tool. Login VSI is a carefully designed, holistic methodology that monitors both hardware resource utilization parameters and EUE during load-testing.

We tested each user load against four runs: a pilot run to validate that the infrastructure was functioning and valid data could be captured, and three subsequent runs to enable data correlation. During testing, while the environment was under load, we logged in to a session and completed tasks that correspond to the user workload. While this test is subjective, it helps to provide a better understanding of the EUE in the desktop sessions, particularly under high load. It also helps to ensure reliable data gathering.

• Compute host servers—VMware vCenter (for VMware vSphere based solutions) or Microsoft Performance Monitor (for Microsoft Hyper-V-based solutions) gathers key data (CPU, memory, disk, and network usage) from each of the compute hosts during each test run. This data is exported to .csv files for single hosts, and then consolidated to show data from all hosts. While the report does not include specific performance metrics for the management host servers, these servers are monitored during testing to ensure that they are performing at an expected level with no bottlenecks.
• Hardware resources—Resource contention, which occurs when hardware resources have been exhausted, can cause poor EUE. We monitored the relevant resource utilization parameters and applied relatively conservative thresholds. Thresholds are carefully selected to deliver an optimal combination of good EUE and cost-per user while also providing burst capacity for seasonal or intermittent spikes in usage. The following table shows the resource utilization parameters and thresholds:

  Table 3. Resource utilization parameters and thresholds

  Parameter	Pass/fail threshold
  Physical host CPU utilization	85%
  Physical host CPU readiness	10%
  Physical host memory utilization	85%
  Network throughput	85%
  Storage I/O latency	20 milliseconds (ms)
  LoginVSI Failed Session	2%

• GPU resources—vSphere Client monitoring collects data about the GPU resource use from a script that is run on VMware ESXi 6.7 and later hosts. The script runs for the duration of the test and contains NVIDIA System Management Interface commands. The commands query each GPU and log the GPU processor, temperature, and memory use to a .csv file. Alternately, VMware vSphere 6.7 and newer has GPU metrics that are built directly into the vSphere Client and API.