Add killer-move ordering and a search benchmark

Killer moves supply the quiet-move ordering the search lacked: ~1.45x faster at depth 8 (up to 1.88x in quiet positions) with identical play. Adds bench.ps1 and test/bench_main.cpp to time the search, with a BENCH_DISABLE_KILLERS compile toggle so the script can measure before/after. Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
2026-06-09 19:01:57 -06:00
parent b651683e63
commit be07f7504e
3 changed files with 251 additions and 19 deletions
@@ -0,0 +1,115 @@
+<#
+.SYNOPSIS
+    Times the search before vs after killer-move ordering.
+
+.DESCRIPTION
+    Compiles two standalone bench binaries from the current engine source — one with killer
+    ordering disabled (the pre-killer baseline, via /DBENCH_DISABLE_KILLERS) and one with it
+    on — then runs each benchmark position in its own process (cold transposition table) and
+    reports wall-clock search time for both, plus the speedup. Timing is measured inside the
+    engine around engine_best_move, so process startup isn't counted. Each position is run
+    -Reps times and the fastest run is kept, to cut scheduling noise.
+
+.PARAMETER Skill
+    Search difficulty / max depth. Default 8.
+
+.PARAMETER Positions
+    Which position indices to run (0=kiwipete, 1=ruy, 2=sicilian). Default: all.
+
+.PARAMETER Reps
+    Runs per position per variant; the minimum time is reported. Default 3.
+
+.PARAMETER ShowDepths
+    Also print every per-depth line the engine emits.
+
+.EXAMPLE
+    .\bench.ps1
+    .\bench.ps1 -Skill 9 -Reps 5 -Positions 0,2
+#>
+[CmdletBinding()]
+param(
+    [int]$Skill = 8,
+    [int[]]$Positions,
+    [int]$Reps = 3,
+    [switch]$ShowDepths
+)
+
+$ErrorActionPreference = 'Stop'
+
+$root  = $PSScriptRoot
+$src   = Join-Path $root 'src'
+$inc   = Join-Path $root 'include'
+$build = Join-Path $root 'build'
+if (-not (Test-Path $build)) { New-Item -ItemType Directory -Path $build | Out-Null }
+
+# --- enter a VS dev shell so cl is on PATH ---
+$devShell = "D:\Program Files\Visual Studio 2026\Common7\Tools\Launch-VsDevShell.ps1"
+if (-not (Test-Path $devShell)) { throw "VS dev shell not found at $devShell" }
+& $devShell -Arch amd64 -HostArch amd64 -SkipAutomaticLocation | Out-Null
+
+$engineSources = 'chess_engine.cpp','bitboard.cpp','zobrist.cpp','position.cpp','movegen.cpp','uci.cpp' |
+    ForEach-Object { Join-Path $src $_ }
+$benchMain = Join-Path $root 'test\bench_main.cpp'
+
+function Build-Variant([string]$exe, [string[]]$extraDefs) {
+    $clArgs = @('/nologo','/std:c++17','/O2','/EHsc','/arch:AVX2','/DCHESS_ENGINE_BUILD','/DNDEBUG') +
+              $extraDefs + @("/I$inc","/I$src", $benchMain) + $engineSources + @("/Fe:$exe", "/Fo:$build\")
+    & cl @clArgs | Out-Null
+    if (-not (Test-Path $exe)) { throw "compile failed: $exe" }
+}
+
+$exeBefore = Join-Path $build 'bench_before.exe'   # killers disabled (pre-killer baseline)
+$exeAfter  = Join-Path $build 'bench_after.exe'    # killers enabled (current)
+
+Write-Host "Compiling both variants..." -ForegroundColor Cyan
+Build-Variant $exeBefore @('/DBENCH_DISABLE_KILLERS')
+Build-Variant $exeAfter  @()
+
+$nodePattern = '^depth (\d+) nodes (\d+) best (\S+) score (-?\d+)$'
+$timePattern = 'time_ms=(\d+)'
+
+function Run-One([string]$exe, [int]$pos) {
+    $nodes = 0; $best = '?'; $bestMs = [long]::MaxValue
+    for ($r = 0; $r -lt $Reps; $r++) {
+        $err = [System.IO.Path]::GetTempFileName()
+        $out = [System.IO.Path]::GetTempFileName()
+        Start-Process -FilePath $exe -ArgumentList $pos,$Skill -NoNewWindow -Wait `
+            -RedirectStandardError $err -RedirectStandardOutput $out | Out-Null
+        $lines = Get-Content $err
+        Remove-Item $err,$out -Force -ErrorAction SilentlyContinue
+        if ($ShowDepths) { $lines | ForEach-Object { Write-Host "  $_" -ForegroundColor DarkGray } }
+
+        $deepest = $lines | Select-String $nodePattern | Select-Object -Last 1
+        if ($deepest) { $nodes = [long]$deepest.Matches.Groups[2].Value; $best = $deepest.Matches.Groups[3].Value }
+        $tm = $lines | Select-String $timePattern | Select-Object -Last 1
+        if ($tm) { $ms = [long]$tm.Matches.Groups[1].Value; if ($ms -lt $bestMs) { $bestMs = $ms } }
+    }
+    return [pscustomobject]@{ Nodes = $nodes; Best = $best; Ms = $bestMs }
+}
+
+if (-not $Positions) { $Positions = 0,1,2 }
+$names = @('kiwipete','ruy','sicilian')
+$rows = @()
+
+foreach ($i in $Positions) {
+    $b = Run-One $exeBefore $i
+    $a = Run-One $exeAfter  $i
+    $speedup = if ($a.Ms -gt 0) { [math]::Round($b.Ms / $a.Ms, 2) } else { 0 }
+    $rows += [pscustomobject]@{
+        Position       = $names[$i]
+        'ms (before)'  = $b.Ms
+        'ms (after)'   = $a.Ms
+        Speedup        = "${speedup}x"
+        'nodes before' = $b.Nodes
+        'nodes after'  = $a.Nodes
+    }
+}
+
+Write-Host ""
+Write-Host "Skill $Skill, best of $Reps runs   (before = no killers, after = killers)" -ForegroundColor Cyan
+$rows | Format-Table -AutoSize
+
+$tb = ($rows | Measure-Object -Property 'ms (before)' -Sum).Sum
+$ta = ($rows | Measure-Object -Property 'ms (after)'  -Sum).Sum
+$tot = if ($ta -gt 0) { [math]::Round($tb / $ta, 2) } else { 0 }
+Write-Host ("TOTAL   {0} ms  ->  {1} ms   ({2}x faster)" -f $tb, $ta, $tot)