fix(benchmark): adapt Measure-CIBenchmark to Linux host

Measure-CIBenchmark.ps1:
- Default params now Linux-aware via $IsWindows conditional
  (TemplatePath, CloneBaseDir, VmrunPath, OutputDir)
- Add -GuestOS Auto/Windows/Linux param; Auto reads VMX guestOS field
  (ubuntu-* → Linux, else Windows)
- Replace Test-NetConnection (Windows-only) with Test-TcpPort helper
  using raw TcpClient async connect — works on PS5.1 and PS7/Linux
- Probe SSH/22 for Linux guests, WinRM/5986 for Windows guests
- Rename winrm→ready throughout ($t, JSONL field readySec, column header)
- Add guestOS field to JSONL output

_Common.psm1 / Invoke-VmrunBounded:
- Replace taskkill /F /T with platform-aware kill:
  Windows → taskkill; Linux → Process.Kill(entireProcessTree) (.NET 5+)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/Measure-CIBenchmark.ps1

@@ -1,63 +1,83 @@
 #Requires -Version 5.1
 <#
 .SYNOPSIS
-    Measures CI infrastructure phase timings: clone, start, IP acquire, WinRM ready, destroy.
+    Measures CI infrastructure phase timings: clone, start, IP acquire, transport ready, destroy.
 
 .DESCRIPTION
     Creates one or more ephemeral VMs from the template, times each phase, destroys
-    them, then prints a summary table. Results are appended to F:\CI\Logs\benchmark.jsonl
+    them, then prints a summary table. Results are appended to benchmark.jsonl
-    for long-term trend tracking (compare before/after §3.1 cache, §3.2 7-Zip, etc.).
+    for long-term trend tracking.
 
     Phases measured:
       clone     — vmrun clone (linked clone from snapshot)
       start     — vmrun start (until command returns)
       ip        — vmrun getGuestIPAddress (polling until IP appears)
-      winrm    — TCP 5986 reachable (polling)
+      ready     — TCP port reachable: 5986 (WinRM, Windows) or 22 (SSH, Linux)
       destroy   — stop + deleteVM + dir removal
 
-    No actual build is run. Phase 5 build timings come from invoke-ci.jsonl logs
+    No actual build is run.
-    produced by Invoke-CIJob.ps1.
 
 .PARAMETER TemplatePath
     Full path to the template VM's .vmx file.
-    Default: F:\CI\Templates\WinBuild2025\WinBuild2025.vmx
 
 .PARAMETER SnapshotName
     Snapshot name to clone from. Default: BaseClean
 
 .PARAMETER CloneBaseDir
-    Directory for ephemeral clone folders. Default: F:\CI\BuildVMs
+    Directory for ephemeral clone folders.
 
 .PARAMETER VmrunPath
-    Path to vmrun.exe.
+    Path to vmrun executable.
-    Default: C:\Program Files (x86)\VMware\VMware Workstation\vmrun.exe
+
+.PARAMETER GuestOS
+    'Windows', 'Linux', or 'Auto' (default). Auto reads guestOS from the VMX:
+    ubuntu-* → Linux (probe SSH/22); anything else → Windows (probe WinRM/5986).
 
 .PARAMETER Iterations
-    Number of clone→ready→destroy cycles to run. Multiple iterations reduce timing
+    Number of clone→ready→destroy cycles to run. Default: 1
-    variance from cold-cache effects. Default: 1
 
 .PARAMETER TimeoutSeconds
-    Maximum seconds to wait for IP and WinRM per iteration. Default: 300
+    Maximum seconds to wait for IP and transport per iteration. Default: 300
 
 .PARAMETER OutputDir
-    Directory where benchmark.jsonl is appended. Default: F:\CI\Logs
+    Directory where benchmark.jsonl is appended.
 
 .EXAMPLE
-    # Single baseline run
+    # Single baseline run (Linux host, Windows template)
     .\Measure-CIBenchmark.ps1
 
-    # 3 iterations for average (first may be slow due to cold host disk cache)
+    # 4 iterations, Linux guest template
-    .\Measure-CIBenchmark.ps1 -Iterations 3
+    .\Measure-CIBenchmark.ps1 -TemplatePath /var/lib/ci/templates/LinuxBuild2404/LinuxBuild2404.vmx `
+        -SnapshotName BaseClean-Linux -Iterations 4
 
-    # Custom snapshot
+    # Windows host
-    .\Measure-CIBenchmark.ps1 -SnapshotName BaseClean_20260510
+    .\Measure-CIBenchmark.ps1 -TemplatePath 'F:\CI\Templates\WinBuild2025\WinBuild2025.vmx' `
+        -Iterations 3
 #>
 [CmdletBinding()]
 param(
-    [string] $TemplatePath   = 'F:\CI\Templates\WinBuild2025\WinBuild2025.vmx',
+    [string] $TemplatePath = $(if ($null -ne $IsWindows -and $IsWindows -eq $false) {
+                                  '/var/lib/ci/templates/WinBuild2025/WinBuild2025.vmx'
+                              } else {
+                                  'F:\CI\Templates\WinBuild2025\WinBuild2025.vmx'
+                              }),
+
     [string] $SnapshotName = 'BaseClean',
-    [string] $CloneBaseDir   = 'F:\CI\BuildVMs',
+
-    [string] $VmrunPath      = 'C:\Program Files (x86)\VMware\VMware Workstation\vmrun.exe',
+    [string] $CloneBaseDir = $(if ($null -ne $IsWindows -and $IsWindows -eq $false) {
+                                  '/var/lib/ci/build-vms/'
+                              } else {
+                                  'F:\CI\BuildVMs'
+                              }),
+
+    [string] $VmrunPath    = $(if ($null -ne $IsWindows -and $IsWindows -eq $false) {
+                                  '/usr/bin/vmrun'
+                              } else {
+                                  'C:\Program Files (x86)\VMware\VMware Workstation\vmrun.exe'
+                              }),
+
+    [ValidateSet('Auto', 'Windows', 'Linux')]
+    [string] $GuestOS = 'Auto',
 
     [ValidateRange(1, 10)]
     [int] $Iterations = 1,
@@ -65,16 +85,49 @@ param(
     [ValidateRange(60, 600)]
     [int] $TimeoutSeconds = 300,
 
-    [string] $OutputDir = 'F:\CI\Logs'
+    [string] $OutputDir = $(if ($null -ne $IsWindows -and $IsWindows -eq $false) {
+                               '/var/lib/ci/logs/'
+                           } else {
+                               'F:\CI\Logs'
+                           })
 )
 
 Set-StrictMode -Version Latest
 $ErrorActionPreference = 'Stop'
-$ProgressPreference   = 'SilentlyContinue'   # suppress Write-Progress (Test-NetConnection, IWR, etc.)
+$ProgressPreference   = 'SilentlyContinue'
 
 Import-Module (Join-Path $PSScriptRoot '_Common.psm1') -Force
 Resolve-VmrunPath -VmrunPath $VmrunPath | Out-Null
 
+# Cross-platform TCP port probe (replaces Test-NetConnection which is Windows-only).
+function Test-TcpPort {
+    param([string]$ComputerName, [int]$Port, [int]$TimeoutMs = 3000)
+    try {
+        $tcp = [System.Net.Sockets.TcpClient]::new()
+        $ar  = $tcp.BeginConnect($ComputerName, $Port, $null, $null)
+        $ok  = $ar.AsyncWaitHandle.WaitOne($TimeoutMs, $false)
+        $connected = $ok -and $tcp.Connected
+        $tcp.Close()
+        return $connected
+    } catch {
+        return $false
+    }
+}
+
+# Resolve effective GuestOS from VMX when Auto.
+$resolvedGuestOS = $GuestOS
+if ($resolvedGuestOS -eq 'Auto') {
+    $vmxRaw = Get-Content -LiteralPath $TemplatePath -Raw -ErrorAction SilentlyContinue
+    if ($vmxRaw -match 'guestOS\s*=\s*"([^"]+)"' -and $Matches[1] -like 'ubuntu*') {
+        $resolvedGuestOS = 'Linux'
+    } else {
+        $resolvedGuestOS = 'Windows'
+    }
+    Write-Host "[bench] GuestOS auto-detected: $resolvedGuestOS"
+}
+$transportPort  = if ($resolvedGuestOS -eq 'Linux') { 22 } else { 5986 }
+$transportLabel = if ($resolvedGuestOS -eq 'Linux') { 'SSH/22' } else { 'WinRM/5986' }
+
 if (-not (Test-Path $TemplatePath -PathType Leaf)) {
     throw "Template VMX not found: $TemplatePath"
 }
@@ -102,7 +155,7 @@ for ($i = 1; $i -le $Iterations; $i++) {
         clone   = $null
         start   = $null
         ip      = $null
-        winrm   = $null
+        ready   = $null
         destroy = $null
         deltaKB = $null
         vmIP    = $null
@@ -151,21 +204,21 @@ for ($i = 1; $i -le $Iterations; $i++) {
         $t.vmIP = $vmIP
         Write-Host "[bench] ip ($vmIP): $($t.ip)s"
 
-        # ── Phase: WinRM ready (poll TCP 5986) ────────────────────────────────
+        # ── Phase: transport ready (SSH/22 for Linux, WinRM/5986 for Windows) ──
-        Write-Host "[bench] Waiting for WinRM (TCP 5986)..."
+        Write-Host "[bench] Waiting for $transportLabel..."
         $sw.Restart()
         $deadline    = (Get-Date).AddSeconds($TimeoutSeconds)
-        $winrmUp  = $false
+        $transportUp = $false
         while ((Get-Date) -lt $deadline) {
-            $winrmUp = Test-NetConnection -ComputerName $vmIP -Port 5986 `
+            $transportUp = Test-TcpPort -ComputerName $vmIP -Port $transportPort
-                           -InformationLevel Quiet -WarningAction SilentlyContinue `
+            if ($transportUp) { break }
-                           -ErrorAction SilentlyContinue
-            if ($winrmUp) { break }
             Start-Sleep -Seconds 3
         }
-        if (-not $winrmUp) { throw "Timed out waiting for WinRM on $vmIP`:5986 after $TimeoutSeconds s" }
+        if (-not $transportUp) {
-        $t.winrm = [math]::Round($sw.Elapsed.TotalSeconds, 2)
+            throw "Timed out waiting for $transportLabel on $vmIP after $TimeoutSeconds s"
-        Write-Host "[bench] winrm: $($t.winrm)s"
+        }
+        $t.ready = [math]::Round($sw.Elapsed.TotalSeconds, 2)
+        Write-Host "[bench] ready ($transportLabel): $($t.ready)s"
     }
     catch {
         $t.error = "$_"
@@ -186,8 +239,8 @@ for ($i = 1; $i -le $Iterations; $i++) {
         }
     }
 
-    $totalBootSec = if ($t.ip -and $t.winrm) {
+    $totalBootSec = if ($t.ip -and $t.ready) {
-        [math]::Round($t.clone + $t.start + $t.ip + $t.winrm, 2)
+        [math]::Round($t.clone + $t.start + $t.ip + $t.ready, 2)
     } else { $null }
 
     $result = [pscustomobject]@{
@@ -196,10 +249,11 @@ for ($i = 1; $i -le $Iterations; $i++) {
         iteration    = $i
         template     = Split-Path $TemplatePath -Leaf
         snapshot     = $SnapshotName
+        guestOS      = $resolvedGuestOS
         cloneSec     = $t.clone
         startSec     = $t.start
         ipSec        = $t.ip
-        winrmSec     = $t.winrm
+        readySec     = $t.ready
         destroySec   = $t.destroy
         totalBootSec = $totalBootSec
         deltaKB      = $t.deltaKB
@@ -226,7 +280,7 @@ $results | Format-Table @(
     @{ L = 'Clone(s)';   E = { $_.cloneSec } }
     @{ L = 'Start(s)';   E = { $_.startSec } }
     @{ L = 'IP(s)';      E = { $_.ipSec } }
-    @{ L = 'WinRM(s)';   E = { $_.winrmSec } }
+    @{ L = 'Ready(s)';   E = { $_.readySec } }
     @{ L = 'Destroy(s)'; E = { $_.destroySec } }
     @{ L = 'Boot total'; E = { $_.totalBootSec } }
     @{ L = 'Delta(KB)';  E = { $_.deltaKB } }
@@ -239,7 +293,7 @@ if ($Iterations -gt 1) {
     if ($ok.Count -gt 0) {
         $avgBoot = [math]::Round(($ok | ForEach-Object { $_.totalBootSec } |
             Measure-Object -Average).Average, 2)
-        Write-Host "Average boot-to-WinRM ($($ok.Count) successful runs): $avgBoot s"
+        Write-Host "Average boot-to-ready ($($ok.Count) successful runs): $avgBoot s"
     }
 }
 

scripts/_Common.psm1

@@ -182,8 +182,13 @@ function Invoke-VmrunBounded {
         # handles held by child processes (e.g. cmd.exe spawning ping.exe in tests,
         # or vmrun spawning helper subprocesses). Plain proc.Kill() only kills the
         # direct process; child processes keep the write end of stdout open.
+        if ($null -ne $IsWindows -and $IsWindows -eq $false) {
+            # .NET 5+ Kill(entireProcessTree) — works on Linux/macOS.
+            $proc.Kill($true)
+        } else {
             & taskkill /F /T /PID $proc.Id 2>&1 | Out-Null
         }
+    }
     $sw.Stop()
 
     $outputText = ''