ATT Trace Viewer (VS Code extension)

Interactive timeline viewer for ROCm Advanced Thread Trace (ATT) inside VS Code, implemented as a Webview.

Key features

• Interactive timeline (x-axis = cycles), per-wave lanes, hover tooltips
• Instruction category coloring + configurable palette (persisted)
• MFMA vs VALU split coloring
• Disassembly pane with:
  • Clickable register tokens (highlight matching/overlapping registers in nearby lines)
  • s_waitcnt dependency hints (polyline arrow to the corresponding memory op)
• Occurrences pane:
  • Lane filter dropdown
  • Δt0 column (delta vs previous occurrence)
• Navigation:
  • Mouse wheel zoom
  • Drag to pan
  • WASD shortcuts (Perfetto-like)
  • Ctrl + left-drag to measure a cycle interval
  • Alt + click to add/remove vertical cycle markers (persisted per trace)

Screenshot

Install (Marketplace)

Install from the VS Code Marketplace:

• VS Code UI: Extensions -> search for ATT Trace Viewer
• CLI: code --install-extension jfactory07.att-trace-viewer

Install (development)

Open this folder in VS Code and run the extension host:

• VS Code: Run and Debug -> Run Extension
• CLI: code --extensionDevelopmentPath=/path/to/vscode-att-viewer

Usage

• Command palette: ATT Viewer: Open ATT Trace
• Explorer context menu on an .att file: ATT Viewer: Open ATT Trace (from file)

The extension will:

1. Look for *_results.db in the same directory as the .att file
2. Use results.db tables rocpd_info_code_object_* to locate *_code_object_id_*.out files
3. Run the bundled python/att2json.py to decode the trace to JSON (cached under VS Code globalStorage)
4. Open a Webview panel to render the timeline

Requirements

• ROCm installed, with:
  • librocprofiler-sdk.so (thread-trace decoder entry points)
  • llvm-objdump at /opt/rocm/llvm/bin/llvm-objdump
• Python 3 available (configurable via attViewer.pythonPath)
• Trace directory should contain:
  • the .att file
  • *_results.db (recommended)
  • *_code_object_id_*.out (code objects)

If *_results.db is missing, the extension falls back to scanning *_code_object_id_*.out files.

Settings

• attViewer.pythonPath (default: python3)
• attViewer.gpuArch (default: gfx950)
• attViewer.maxEvents (default: 0 = all; for large traces, start with e.g. 200000)

Keyboard and mouse shortcuts

Timeline:

• Mouse wheel: zoom (cursor-anchored)
• Drag: pan
• WASD: pan/zoom (Perfetto-like)
• Shift + WASD: faster pan/zoom
• Ctrl + left-drag: measure cycle interval (shows Δcycles)
• Alt + click: add/remove a vertical cycle marker

Disassembly:

• Click a register token (e.g. v78, v[98:101], s61) to highlight matching registers in nearby lines
• Select s_waitcnt lgkmcnt(N) / vmcnt(N) to show a polyline arrow to the corresponding previous memory op

Troubleshooting

• Decode fails / missing ROCm libs: ensure ROCm is installed and /opt/rocm/lib exists. The extension sets LD_LIBRARY_PATH=/opt/rocm/lib.
• No disassembly: verify llvm-objdump exists at /opt/rocm/llvm/bin/llvm-objdump and attViewer.gpuArch matches your code object architecture.
• Large traces are slow: set attViewer.maxEvents to a smaller value for faster iteration.

Changelog

See CHANGELOG.md.