I – La moins évidente : en utilisant directement les objets du Framework .NET :

1- Afficher le % d’utilisation du processeur sur une instance de processeur :

$ProcTime=New-Object System.Diagnostics.PerformanceCounter("Processor","% Processor Time", "0")

$ProcTime.NextValue()

2- Afficher la liste des compteurs et toutes leurs propriétés :

$proc = New-Object System.Diagnostics.PerformanceCounterCategory("Processor")

$proc.GetCounters(0) 

CategoryName     : Processor
CounterHelp      : % Processor Time is the percentage of elapsed time that the processor spends to execute a non-Idle thread. It is calculated by measuring the percentage of time that the pro
                   cessor spends executing the idle thread and then subtracting that value from 100%. (Each processor has an idle thread that consumes cycles when no other threads are ready t
                   o run). This counter is the primary indicator of processor activity, and displays the average percentage of busy time observed during the sample interval. It should be note
                   d that the accounting calculation of whether the processor is idle is performed at an internal sampling interval of the system clock (10ms). On todays fast processors, % Pr
                   ocessor Time can therefore underestimate the processor utilization as the processor may be spending a lot of time servicing threads between the system clock sampling interv
                   al. Workload based timer applications are one example  of applications  which are more likely to be measured inaccurately as timers are signaled just after the sample is ta
                   ken.
CounterName      : % Processor Time

etc….

3- Afficher la liste des compteurs de performance pour un objet/catégorie :

$proc.GetCounters(0) | select CounterName

Autre tip : pour afficher les résultats dans un tableau à part sur lequel on peut faire jouer les filtres, rajouter un “pipe” avec “out-gridview” (comme on pourrait mettre “format-list” ou “fl” ou “format-table” ou “ft”)

$proc.GetCounters(0) | select CounterName | out-gridview

II – La plus simple : en utilisant directement les fonctions PowerShell

Name                              Category  Synopsis                                                                                                                                          
----                              --------  --------                                                                                                                                          
Get-Counter                       Cmdlet    Gets performance counter data from local and remote computers.                                                                                    
Import-Counter                    Cmdlet    Imports performance counter log files (.blg, .csv, .tsv) and creates the objects that represent each counter sample in the log.                   
Export-Counter                    Cmdlet    The Export-Counter cmdlet takes PerformanceCounterSampleSet objects and exports them as counter log files.                             

get-counter -Counter "\Processor(*)\% Processor Time" -computername localhost