Accordo: GPU Kernel Validation

Capture and compare kernel outputs from reference and optimized binaries to validate correctness. Uses kernelDB for automatic kernel extraction; supports configurable tolerance and execution-time comparison.

When to Use

• User has a reference and an optimized (or modified) GPU kernel and wants to check they produce the same results
• Regression testing after kernel or build changes
• Validating multiple optimization variants against one baseline

Instructions

1. Require two or more binaries: one reference (e.g. ./app_ref) and one or more to validate (e.g. ./app_opt). All must expose the same kernel by name.
2. Ensure binaries are built with debug symbols (-g) so kernel arguments can be extracted.
3. Choose execution path:
   • If an Accordo MCP server is available, call its validate_kernel_correctness tool, which performs capture-and-compare with the same semantics described below.
   • Otherwise use the Python API or the accordo validate CLI (accordo validate --help for flags: --kernel-name, --ref-binary, --opt-binary, --tolerance, --timeout, --working-dir, --kernel-args, --log-level).

Python API

from accordo import Accordo

# Validator for the kernel to validate (binary used to extract signature)
validator = Accordo(binary="./app_ref", kernel_name="reduce_sum")

# Optional: set working directory if binaries expect it
validator = Accordo(binary="./app_ref", kernel_name="reduce_sum", working_directory="./run")

# Capture snapshots
ref = validator.capture_snapshot(binary="./app_ref")
opt = validator.capture_snapshot(binary="./app_opt")

# Compare with tolerance (default 1e-6)
result = validator.compare_snapshots(ref, opt, tolerance=1e-6)

if result.is_valid:
    print("PASS:", result.num_arrays_validated, "arrays matched")
else:
    print(result.summary())

For multiple optimizations, capture the reference once and compare each optimized snapshot against it.

Snapshot and result attributes

• Snapshot: arrays, execution_time_ms, grid_size, block_size
• ValidationResult: is_valid, num_arrays_validated, num_mismatches, mismatches, success_rate; use summary() for a human-readable report.

Workflow

1. Build reference and optimized binaries with the same kernel name and -g.
2. Create an Accordo(binary=ref_binary, kernel_name="...") validator; set working_directory if needed.
3. Capture reference snapshot with capture_snapshot(binary=ref_binary).
4. For each variant, capture with capture_snapshot(binary=opt_binary) and compare with compare_snapshots(ref, opt, tolerance=...).
5. If result.is_valid is false, use result.summary() and result.mismatches to diagnose.
6. Use relative paths for binaries and working directory so the skill is portable.

Notes

• kernelDB is used automatically; no separate kernelDB setup is required when using the Python API.
• Increase tolerance for floating-point comparisons when appropriate (e.g. 1e-4 or 1e-5 for single precision).
• Use timeout_seconds in capture_snapshot if the run may hang.