LingSys

# HatchMEM sampler: writes a small text snapshot of Windows memory counters for hatchmem.ling.
#
# Ling has no builtin that reads operating-system memory, so this script is the only bridge.
# It never touches process memory: it reads the same performance counters Task Manager shows.
# Output (mem.snap, replaced atomically each tick), one record per line, fields split by '|':
#   t|<unix seconds>
#   g|total|avail|free|standby|modified|nonpaged|paged|compressed|committed|commit_limit|cache      (MB)
#   r|faults|reads|writes|pages_in|pages_out|demand_zero|cache_faults|copy_writes                   (per second)
#   p|name|pid|working_set|private|io_read|io_write|faults                                          (MB, MB, KB/s, KB/s, /s)
param(
    [string]$Out = (Join-Path $PSScriptRoot 'mem.snap'),
    [double]$Interval = 0.5,
    [int]$Top = 28,
    [switch]$Once,
    [int]$ParentPid = 0     # exit when this process is gone (the exe starts the samplers and passes its own id)
)
$ErrorActionPreference = 'Stop'
$MB = 1MB
$total = [double](Get-CimInstance Win32_ComputerSystem).TotalPhysicalMemory
$inv = [Globalization.CultureInfo]::InvariantCulture
function F($v) { ([double]$v).ToString('0.##', $inv) }

do {
    if ($ParentPid -gt 0 -and -not (Get-Process -Id $ParentPid -ErrorAction SilentlyContinue)) { break }
    $t0 = Get-Date
    $m = Get-CimInstance Win32_PerfFormattedData_PerfOS_Memory
    $procs = Get-CimInstance Win32_PerfFormattedData_PerfProc_Process |
        Where-Object { $_.Name -ne '_Total' -and $_.Name -ne 'Idle' }
    $zip = ($procs | Where-Object { $_.Name -eq 'Memory Compression' } | Select-Object -First 1).WorkingSetPrivate
    $standby = [double]$m.StandbyCacheCoreBytes + $m.StandbyCacheNormalPriorityBytes + $m.StandbyCacheReserveBytes

    $lines = New-Object System.Collections.Generic.List[string]
    $lines.Add('t|' + [DateTimeOffset]::UtcNow.ToUnixTimeSeconds())
    $lines.Add('g|' + (@($total, $m.AvailableBytes, $m.FreeAndZeroPageListBytes, $standby, $m.ModifiedPageListBytes,
        $m.PoolNonpagedBytes, $m.PoolPagedBytes, $zip, $m.CommittedBytes, $m.CommitLimit, $m.CacheBytes |
        ForEach-Object { F ($_ / $MB) }) -join '|'))
    $lines.Add('r|' + (@($m.PageFaultsPersec, $m.PageReadsPersec, $m.PageWritesPersec, $m.PagesInputPersec,
        $m.PagesOutputPersec, $m.DemandZeroFaultsPersec, $m.CacheFaultsPersec, $m.WriteCopiesPersec |
        ForEach-Object { F $_ }) -join '|'))

    # Private bytes of everything (for the DATA slice), then the biggest few for the process views.
    $privAll = ($procs | Measure-Object WorkingSetPrivate -Sum).Sum
    $lines.Add('s|' + (F ($privAll / $MB)) + '|' + $procs.Count)
    foreach ($p in ($procs | Sort-Object WorkingSet -Descending | Select-Object -First $Top)) {
        $name = ($p.Name -replace '[|#\r\n]', '_')
        $lines.Add('p|' + $name + '|' + $p.IDProcess + '|' + (F ($p.WorkingSet / $MB)) + '|' +
            (F ($p.WorkingSetPrivate / $MB)) + '|' + (F ($p.IOReadBytesPersec / 1KB)) + '|' +
            (F ($p.IOWriteBytesPersec / 1KB)) + '|' + (F $p.PageFaultsPersec))
    }
    $tmp = "$Out.tmp"
    [IO.File]::WriteAllText($tmp, ($lines -join "`n") + "`n")
    Move-Item -Force $tmp $Out
    if ($Once) { break }
    $left = $Interval - ((Get-Date) - $t0).TotalSeconds
    if ($left -gt 0) { Start-Sleep -Milliseconds ([int]($left * 1000)) }
} while ($true)