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Workspace Environment Management (WEM) uses intelligent resource (RAM, CPU, and I/O) and profile management technologies to deliver the best performance, desktop logon, and application response times for Citrix XenApp/XenDesktop deployments. CPU Management Settings offered by WEM lets you limit CPU capacity that cab used by individual processes in the XenApp environment where a large number of processes are running across all cores and using up as much CPU as they require. CPU spike protection feature of WEM CPU Management Settings is designed to reduce the impact on user experience by processes that consume an excessive percentage of CPU. When CPU spike protection is enabled, if a process reaches a specified threshold, WEM automatically lowers the priority of the process for a certain time. Then, when a new application is launched, it has a higher priority than the lower-priority process and the system will continue to run smoothly. Likewise, CPU clamping feature in WEM prevents processes using more than a specified percentage of the CPU's processing power. If a process reaches the specified CPU percentage, WEM “throttles” (or “clamps”) that process, thus preventing processes from consuming large amount of CPU. This way, overall VM performance degradation due to CPU heavy processes can be prevented, and user experience can be improved in the XenApp/XenDesktop environment where all users would be effected by a rogue process consuming too much CPU.

To obtain a clear picture of the impact of CPU management features of WEM on XenApp / XenDesktop VM performance, you can use the CtxXcXAWemCpuTest test. This test reports the total number of processes and the unique processes that are affected by CPU spike protection feature. These metrics help you find out how many CPU-intensive processes are currently running in the environment. In the process, this test also reveals the configured CPU usage limit, how long the CPU usage limit is being violated by the processes and how long the processes are at lower priority due to violation of CPU usage limit. This way, the test alerts you if the priority of any process has been reduced because of CPU Spikes Protection. Besides, this tests also captures the count of processes that have been throttled owing to CPU clamping.

Outputs of the test :One set of results for the Citrix XenApp server that is being monitored

Measurement	Description	Measurement Unit	Interpretation
No_of_process	Indicates the total number of processes affected by WEM CPU spikes protection.	Number	A high value for this measure indicates that more number of CPU-intensive processes are running in the XenApp environment.
NO_of_unq_process	Indicates the number of unique processes affected by WEM CPU spikes protection.	Number
Threshold_tym	Indicates the percentage of CPU usage that any process instance must reach to trigger CPU spike protection.	Percent	This limit is global across all logical processors in the server, and is determined on an instance-by-process basis. Multiple instances of the same process do not have their CPU usage percentage added when determining CPU spike protection triggers. If a process instance never reaches this limit, CPU spike protection will not be triggered.
Sample_tym	Indicates the time period during which a process exceeds the CPU usage limit before its CPU priority is lowered.	Seconds
Idle_tym	Indicates the time period during which the CPU priority of the process is lowered.	Seconds
Clamping_proc	Indicates the number of processes configured with CPU clamping.	Number	CPU clamping is best reserved for controlling processes that are notoriously bad at resource management, but that cannot stand to be dropped in priority. CPU Clamping prevents a process from consuming more than a set percentage of a processor's resources.
Total_clamp	Indicates the number of processes throttled by WEM CPU clamping as they exceeded the configured CPU usage percentage.	Number