XFESystem

{
  "Kind": "XfeMonacoStutterInvestigation",
  "Date": "2026-10-16",
  "ImplementationCommit": "653f0594e5bdfc3d90ad3c2929c5526a6fb9edaf",
  "BaselineCommit": "33ec2b5bec724afac0dd235e9ff9550c860ba936",
  "FullReleaseQualified": false,
  "PhysicalUsbWritten": false,
  "ReleaseZipCreated": false,
  "ImplementationFilesSha256": {
    "Source/XFESystem.Browser/BrowserCssCascade.cs": "3468dcaccf2cde5345c9ee0534a668d69fc451d5da0da0786a1db4e8bce40b5d",
    "Source/XFESystem.Browser/BrowserInteractivePage.cs": "07b27a24853033695ec06a6a5ee22ae24ad04070933522a1916944e0112ac794",
    "Source/XFESystem.Browser/CssComputedStyle.cs": "d11f72354d2aee42c82818bd153f8d8eddfcb638befdbb9bf3b64ec7bb1b18da",
    "Source/XFESystem.Browser/CssPropertyMap.cs": "1be9087ede5090f91f67d77409822d52f119267e0d4df3b594b86c9ff6e77591",
    "Source/XFESystem.Browser/DomBridge.cs": "6d69302f2ea4e3546700ba525035523ce5d62b6ccb62f52039f7494456cc0c5d",
    "THIRD_PARTY.md": "1844b02ab2991050384947178230068e91af698f94e9721a274dabb03ce92c24",
    "Tests/XFESystem.Browser.Tests/CssPropertySharingTests.cs": "293458a0659b6bbbea81c682902503727e427cea54bf33cede8c4b2a5edc1b38",
    "Tests/XFESystem.JintCleanupPatch.Tests/RegexSearchTests.cs": "3f3c4bb42dc5f3e3fc7b8e1951b85eeafe14124403574996446edc9ba5971802",
    "Tools/BrowserCompatibility/PreviewProfile/CompareMonaco.ps1": "14a7f6383ce40c633d33adb09d4773b4e84178cda9d163f0da75de74d4b9c51f",
    "Tools/BrowserCompatibility/PreviewProfile/MonacoProfile.cs": "ebd101746d3ee804399025d94066ac7b500d9184fb8496cbaf0c732f48c590f0",
    "Tools/BrowserCompatibility/PreviewProfile/MonacoRegexProfile.cs": "c5008f437b11a47163164ac1380893922bc9d4801abd4fbd4d21fe964bee34cd",
    "Tools/BrowserCompatibility/PreviewProfile/Program.cs": "306cd3a05b45f63f956cba53e6ffe3be37810ba4695931680d8d36268d1ccad7",
    "Tools/IndependentKernel/TestMonacoStartup.py": "0b999947599ecf06c5de3078acfc3dde7a7a7fd25c2a3e11d17bb48bd188ba4c",
    "Tools/JintCleanupPatch/BoundTargets.cs": "3c882fe0d5cfabb5e213fceead1d819545408b90ffccbc5e5192ecc8c1eaedf1",
    "Tools/JintCleanupPatch/Program.cs": "bd5e22df1f1dc216e336573f7a238966e2dd3becc4f3674032ca61ea16fe83cb",
    "Tools/JintCleanupPatch/RegexSearch.cs": "21f7cac4337d04dac8eab9d3019ad1ecc89aecd32a065dde00e369c9467242e5"
  },
  "ImplementationFilesMatchCommitBytes": true,
  "UpstreamBrowserAssetsUnchanged": true,
  "RootCauses": [
    "Repeated failed custom-RegExp suffix searches inside website C# highlighting.",
    "Entire CSS custom-property environments copied and resolved per descendant per layout.",
    "Jint interprets JS. NativeAOT compiles the interpreter, not JavaScript. Actual BSP=1, software drawing, concurrent GC disabled; GC pause durations not separately measured."
  ],
  "RegexDiagnostic": {
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      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\RegexBaseline-1792094998815\\Result.json",
      "Sha256": "d37bd068e25f507c8570dcc7dcb97cef12fa0a12c3f93964ea613831f8511032"
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    "After": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\RegexAfter-1792095918846\\Result.json",
      "Sha256": "dfa0edc2d8684dd0a374dea69247beeb9a2c6c6ca29677673cc234b4c1e43741"
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    "PatternWithFlagsCharacters": 4243,
    "PatternSha256": "a806cb9cab810b4cbc169d726ef1d1e1f8a6d7938cc8be21956767c37afb4d18",
    "BeforeCalls": 256,
    "AfterCalls": 256,
    "AfterFailedSuffixHits": 255,
    "BeforeMilliseconds": 2201.8803,
    "AfterMilliseconds": 17.9791,
    "DiagnosticOnly": true,
    "Method": "Wrapper calls original intrinsic without resetting budgets. Timing includes diagnostic overhead; primary initialization performance comes from the isolated comparison."
  },
  "CpuSamples": {
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      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\StutterBaseline.nettrace",
      "Sha256": "84c6e64f75d6e1d158733756e4e14bce0dbe6ff47197ede10dba141b0b2af3e8"
    },
    "Speedscope": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\StutterBaseline.speedscope.json",
      "Sha256": "1979c2139624d5eb92904d650834f6542d628d1f5c014eb9d7f8f2f740cacd7a"
    },
    "HostOnly": true
  },
  "HostComparison": {
    "Evidence": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\HostComparison-1792095812701\\Comparison.json",
      "Sha256": "2775006e9d07073b283060f9355c8bf6637a9f1cc8d082b851d4faf1a7497a9a"
    },
    "BeforeSamples": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\HostComparison-1792095812701\\Baseline\\build\\MonacoInit\\Before-1792095832810\\Result.json",
      "Sha256": "36a0a2805fd37136c46d1b89eab2922527c3acd4b768df4bf10330f74273cb35"
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    "AfterSamples": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\After-1792095863040\\Result.json",
      "Sha256": "099a80069139e589357540d89a4deb7aca81a7ff5efbe8d969183c1ea5eb5907"
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    "Rows": [
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        "Kind": "ShortCSharp",
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        "AfterMedianMilliseconds": 405.1336,
        "Speedup": 1.3942146491922665,
        "BeforeTokenizationFullModelReads": 0,
        "AfterTokenizationFullModelReads": 0,
        "BeforeAllocatedBytes": 321358032,
        "AfterAllocatedBytes": 253815424,
        "ActualViewTokensEqual": true
      },
      {
        "Kind": "LongCSharp",
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        "AfterMedianMilliseconds": 736.2649,
        "Speedup": 4.3143891553162454,
        "BeforeTokenizationFullModelReads": 0,
        "AfterTokenizationFullModelReads": 0,
        "BeforeAllocatedBytes": 374076008,
        "AfterAllocatedBytes": 227295136,
        "ActualViewTokensEqual": true
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    ],
    "BeforeRuntimeJintSha256": "4bef737aedf8dbb5e3a2a006928e2b689dce290c48493dce088661a4099413a3",
    "AfterRuntimeJintSha256": "9c0c7e7a44d3fa9d0c857ff9037994b785294a142467ba5a61706611c81d7090",
    "Method": "Five fresh engines per case; exact archived baseline and archived build/patch targets; same current probe; TieredCompilation=0. First short case includes cold parsing. Windows host, actual real-font view/paint and editing."
  },
  "NativeComparison": {
    "Evidence": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\NativeComparison-1792095593970527400\\Comparison.json",
      "Sha256": "1f2de09c6c8e0578559338f7bcf48cbe0d9d4b6e7cb6ec2cd9778c23c6e37257"
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    "Before": {
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    "After": {
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    "ArchivedHarness": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\NativeComparison-1792095593970527400\\Harness.py",
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    "BeforeWarmMedianMilliseconds": 7906.0,
    "AfterWarmMedianMilliseconds": 4898.0,
    "AllNativeViewportPixelsEqual": true,
    "ExactModelsEqual": true,
    "BothImagesPassedActualKeyboardEditing": true,
    "ColdSamplesPerImage": 1,
    "WarmSamplesPerImage": 2,
    "VirtualCpus": 8,
    "ExecutingCpus": 1,
    "Gpu": false,
    "Prewarmed": false,
    "Method": "QEMU TCG, PS/2 input, exact model and stable native glyph frame; IDE snapshot with explicit RAM fallback for timing. Persistent USB separately tested using a private virtual image."
  },
  "ResponsivenessControl": {
    "Evidence": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\IdleControl-1792096125321554100\\Result.json",
      "Sha256": "b65870869131745a8a440d017af58130ec72dd84a352e0ba1bc2c28d005d1569"
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    "Kind": "ActualDesktopStartMenuDuringWorkerScript",
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    "IdleKeyboardToPresentedMenuMilliseconds": 218.0,
    "ExtraInitializationLatencyMilliseconds": 16.0,
    "InitializationStillRunningAtMenuPresentation": true,
    "TimingIncludesQmpAndSerialPolling": true,
    "HostScreenshotSubstitution": false,
    "Samples": 1,
    "NoGeneralSmoothnessOrHardwareLatencyClaim": true
  },
  "Regressions": {
    "Suites": [
      {
        "Suite": "Browser",
        "Passed": 448,
        "Failed": 0,
        "Evidence": {
          "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\Regression\\Browser.trx",
          "Sha256": "b3c9041595a8e1964741fd94858372125d40ceae52f320408f3a6d613d2b5f64"
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      },
      {
        "Suite": "JintCleanupPatch",
        "Passed": 40,
        "Failed": 0,
        "Evidence": {
          "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\RegressionFinal\\JintCleanupPatch.trx",
          "Sha256": "8fed1b370e9b42c8f67a63ab42fc8445d3d9803b1ebecfad13e226584f2106de"
        }
      }
    ],
    "NativeDesktopBrowserProof": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\IndependentKernel\\Proof-1792095440715901500\\Result.json",
      "Sha256": "31d02d9275510658b170e5ce44a0c987815f431e27317dfe615ed931ac8d9ee8"
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    "NativeBoundInputs": 493,
    "NativeBindingUnchanged": true,
    "NativeSourceSnapshot": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\IndependentKernel\\Proof-1792095440715901500\\SourceSnapshot.json",
      "Sha256": "a5045c788dc77fd5fd82ca4c8fe054f7c22c4eeae2f31e73b54195f5d5c66847"
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    "NativeImage": {
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    "PrivateVirtualUsbStorageRegression": {
      "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\IndependentKernel\\UsbStorage-1792095444217676500\\Result.json",
      "Sha256": "bda63b12ce10c4c17de098f460f4ad7a2f4f9f36ff598be07dcc741d5eb100a8"
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    "Full16SuiteHostReleaseRun": false,
    "BingRevalidated": false,
    "FullDocumentsRevalidated": false,
    "PhysicalHardwareRevalidated": false
  },
  "RetainedRejectedMeasurements": [
    {
      "Evidence": {
        "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\HostComparison-1792095711332\\Comparison.json",
        "Sha256": "80d0a27adf09f17fa9327032bb1c4a3e3aeea9eab4b1616d34e9c1cebc94b764"
      },
      "Reason": "Probe outside archived tree inherited current Jint patch target; both processes loaded new Jint. Superseded for full-patch performance."
    },
    {
      "Evidence": {
        "Path": "C:\\Users\\XFEstudio\\.codex\\worktrees\\browser-load-speed\\XFESystem\\build\\MonacoInit\\IdleControl-1792095946154434100\\Result.json",
        "Sha256": "bccc8cd0c049c1d76ede62ab4d117326f146543e17341ef190acaa22e5126a9f"
      },
      "Reason": "Ctrl+Esc is routed to the focused page, so idle menu control timed out while Monaco rendered. Corrected control uses global Windows-key release."
    }
  ],
  "References": [
    "https://github.com/v8/v8/blob/main/src/regexp/regexp.cc",
    "https://github.com/v8/v8/blob/main/src/regexp/regexp-interpreter.cc",
    "https://v8.dev/blog/regexp-tier-up",
    "https://v8.dev/blog/sparkplug",
    "https://github.com/sebastienros/jint/blob/v4.11.0/Jint/Native/RegExp/RegExpPrototype.cs"
  ]
}