$server = "(local)"
$uid = "sa"
$db="master"
$pwd="pwd"
$mailprfname = "sina"
$recipients = "xxxxx@qq.com"
$subject = "Proformance Alter"
$computernamexml = "f:\computername.xml"
$alter_cpuxml = "f:\alter_cpu.xml"
function GetServerName($xmlpath)
{
    $xml = [xml] (Get-Content $xmlpath)
    $return = New-Object Collections.Generic.List[string]
    for($i = 0;$i -lt $xml.computernames.ChildNodes.Count;$i++)
    {
        if ( $xml.computernames.ChildNodes.Count -eq 1)
        {
            $cp = [string]$xml.computernames.computername
        }
        else
        {
            $cp = [string]$xml.computernames.computername[$i]
        }
        $return.Add($cp.Trim())
    }
    $return
}

function GetAlterCounter($xmlpath)
{
    $xml = [xml] (Get-Content $xmlpath)
    $return = New-Object Collections.Generic.List[string]
    $list = $xml.counters.Counter
    $list
}

function CreateAlter($message)
{
    $SqlConnection = New-Object System.Data.SqlClient.SqlConnection 
    $CnnString ="Server = $server; Database = $db;User Id = $uid; Password = $pwd" 
    $SqlConnection.ConnectionString = $CnnString 
    $CC = $SqlConnection.CreateCommand(); 
    if (-not ($SqlConnection.State -like "Open")) { $SqlConnection.Open() } 
    
    $cc.CommandText=" EXEC msdb..sp_send_dbmail 
            @profile_name  = '$mailprfname'
            ,@recipients = '$recipients'
            ,@body = '$message'
            ,@subject = '$subject'
" 
    $cc.ExecuteNonQuery()|out-null 
    $SqlConnection.Close();
}

$names = GetServerName($computernamexml)
$pfcounters = GetAlterCounter($alter_cpuxml)
foreach($cp in $names)
{
    $p = New-Object Collections.Generic.List[string]
    $report = ""
    foreach ($pfc in $pfcounters)
    {
        $b = ""
        $counter ="\\"+$cp+$pfc.get_InnerText().Trim()
        $p.Add($counter)
        
    }
    $count = Get-Counter $p
    for ($i = 0; $i -lt $count.CounterSamples.Count; $i++)
    {
        $v = $count.CounterSamples.Get($i).CookedValue
        $pfc = $pfcounters[$i]
        #$pfc.get_InnerText()
        $b = ""
        $lg = ""
        if($pfc.operator -eq "lt")
        {
            if ($v -ge [double]$pfc.alter)
                {$b = "alter"
                $lg = "Greater Than"}
        }
        elseif ($pfc.operator -eq "gt")
        {
            if( $v -le [double]$pfc.alter)
                {$b = "alter"
                $lg = "Less Than"}
        }
        if($b -eq "alter")
        {
            $path = "\\"+$cp+$pfc.get_InnerText()
            
            $item = "{0}:{1};{2} Threshold:{3}" -f $path,$v.ToString(),$lg,$pfc.alter.Trim()
            $report += $item + "`n"
        }
        
    }
    if($report -ne "")
    {
        #生产警告 参数 计数器，阀值，当前值
        CreateAlter $report
    }
}

<computernames>
        <computername>
                fanr-pc
        </computername>
</computernames>

<Counters>
      <Counter alter = "10" operator = "gt" >\Processor(_Total)\% Processor Time</Counter>
        <Counter alter = "10" operator = "gt" >\Processor(_Total)\% Privileged Time</Counter>
        <Counter alter = "10" operator = "gt" >\SQLServer:SQL Statistics\Batch Requests/sec</Counter>
        <Counter alter = "10" operator = "gt" >\SQLServer:SQL Statistics\SQL Compilations/sec</Counter>
        <Counter alter = "10" operator = "gt" >\SQLServer:SQL Statistics\SQL Re-Compilations/sec</Counter>
        <Counter alter = "10" operator=  "lt" >\System\Processor Queue Length</Counter>
        <Counter alter = "10" operator=  "lt" >\System\Context Switches/sec</Counter>
</Counters>