WS9: Integration & Verification

Owner: TBD Team Size: 4-5 engineers Duration: 16-20 weeks Priority: Critical

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Objectives

Full system integration, ISA compliance verification, and Linux distribution validation.

Overview

WS9 is the final and most critical workstream. This is where all previous workstreams (WS1-WS8) are integrated, tested, and validated against the Power ISA v3.1C specification. The goal is to achieve OpenPOWER certification and boot unmodified Linux distributions.

This workstream answers the key question: “Does the upgraded A2 core actually work?”

Major Phases

Phase 1: Integration (Weeks 1-5)
  └─ Merge all workstreams, resolve conflicts, run initial sanity tests

Phase 2: Compliance Testing (Weeks 6-12)
  └─ Run official ISA test suite, fix bugs, achieve 100% pass rate

Phase 3: Linux Validation (Weeks 13-16)
  └─ Boot Linux distributions, run application workloads

Phase 4: Performance & Release (Weeks 17-20)
  └─ Performance benchmarking, documentation, release preparation

Tasks

Phase 1: Integration (Weeks 1-5)

Phase 2: Compliance Testing (Weeks 6-12)

Phase 3: Linux Validation (Weeks 13-16)

Phase 4: Performance & Release (Weeks 17-20)

Testing Infrastructure

Simulation Platform

• RTL Simulation: Verilator or commercial simulator
• Cycle-accurate: Full instruction execution trace
• Speed: 10-100 KHz (slow but accurate)
• Usage: Early testing, debug

FPGA Platform

• Device: Xilinx VCU-118 or similar
• Speed: 50-200 MHz (1000x faster than simulation)
• Usage: Linux boot, extended testing, demos

Silicon Platform (future)

• Post-silicon validation
• Production frequency: 3+ GHz
• Final performance benchmarks

Compliance Test Details

OpenPOWER Foundation Tests

• Source: https://github.com/OpenPOWER-Foundation
• Format: Self-checking test programs
• Coverage: All three ISA books
• Expected runtime:
  • Simulation: 2-4 weeks
  • FPGA: 2-3 days
  • Silicon: Hours

Linux Test Project (LTP)

• Source: https://github.com/linux-test-project/ltp
• Tests: 3000+ system calls and APIs
• Coverage: OS-level ISA compliance
• Runtime: 12-24 hours

glibc Test Suite

• Source: glibc source tree
• Coverage: C standard library
• Critical for: VMX/VSX validation in libc
• Runtime: 4-8 hours

KVM Selftests

• Source: Linux kernel tools/testing/selftests/kvm/
• Coverage: Hypervisor functionality
• Tests: 50+ KVM-specific tests
• Runtime: 1-2 hours

Risk Management

High-Risk Areas

1. Radix MMU (WS4): Most complex, highest bug risk
2. VMX/VSX (WS7): Largest instruction set, most test cases
3. Hypervisor (WS2): Complex interactions with MMU and interrupts
4. Timing Closure: New features may impact frequency

Mitigation Strategies

1. Early Integration: Don’t wait for WS1-8 completion
2. Incremental Testing: Test as workstreams complete
3. Parallel Debug: Multiple engineers debugging simultaneously
4. Automated Regression: Catch regressions immediately
5. FPGA Early Access: Test on real hardware ASAP

Schedule Buffers

• Phase 1: 1 week buffer (integration conflicts)
• Phase 2: 2 week buffer (compliance test failures)
• Phase 3: 1 week buffer (Linux issues)
• Phase 4: 1 week buffer (documentation and release prep)

Success Criteria

Mandatory (Must Pass)

• 100% ISA compliance test pass rate
• Boots mainline Linux kernel
• At least one Linux distribution boots to login
• All 4 threads functional
• No critical bugs
• Meets frequency target (within 90%)

Highly Desired (Should Pass)

• Multiple Linux distributions boot
• KVM functionality validated
• 24+ hour stability test passes
• Performance within 10% of target
• All documentation complete

Nice to Have (May defer)

• SPEC benchmark results
• Power consumption optimization
• Commercial OS support (if applicable)

Go/No-Go Decision Points

Week 5: Integration Checkpoint

• Go criteria: Clean compilation, smoke tests pass
• No-go: Merge conflicts unresolved, synthesis fails

Week 12: Compliance Checkpoint

• Go criteria: 95%+ test pass rate, path to 100% clear
• No-go: <90% pass rate, critical bugs unfixable

Week 16: Linux Checkpoint

• Go criteria: Linux boots, basic functionality works
• No-go: Kernel panics, major stability issues

Week 20: Release Decision

• Go criteria: All mandatory criteria met
• No-go: Critical bugs remain, compliance <100%

Resource Requirements

Engineering Team

• Integration Lead: 1 (coordinates all activities)
• Verification Engineers: 2-3 (run tests, debug failures)
• RTL Engineers: 1-2 (fix bugs, code changes)
• Software Engineers: 1 (Linux kernel and distros)
• Performance Engineer: 1 (benchmarking and optimization)

Compute Resources

• High-performance simulation servers (8-16 core, 64GB+ RAM)
• Multiple FPGA boards (2-4 VCU-118 or equivalent)
• Storage for test results and waveforms (1TB+)

Software Tools

• RTL simulator license (if commercial)
• Synthesis and P&R tools (Vivado, etc.)
• Power ISA compliance test suite
• Linux distributions
• Benchmark software

Deliverables

Technical

1. ✅ Fully integrated A2 v3.1C RTL
2. ✅ 100% passing ISA compliance tests
3. ✅ Booting Linux distributions
4. ✅ FPGA bitstream
5. ✅ Test reports and coverage analysis

Documentation

1. ✅ Architecture manual
2. ✅ Programmer’s guide
3. ✅ Integration manual
4. ✅ Test plan and results
5. ✅ Release notes

Release

1. ✅ Tagged Git repository
2. ✅ Source code package
3. ✅ Binary releases (bitstreams)
4. ✅ Project website update

Dependencies

• Depends on: All workstreams (WS1-WS8)
• Blocking: None (this is final phase)
• Critical Path: WS9 is on the critical path for project completion

Timeline Visualization

Week   Activity                           Milestone
----   --------                           ---------
1-5    Integration & Smoke Testing       ✓ Clean build
6-12   ISA Compliance Testing            ✓ 100% pass rate
13-16  Linux Validation                  ✓ Distro boots
17-20  Performance & Release             ✓ Release ready

Risk Windows:
Week 6-8:   High (compliance test failures expected)
Week 13-14: Medium (Linux boot issues possible)
Week 18-20: Low (polish and documentation)

References

• OpenPOWER Foundation: Compliance Test Suite
• Linux Test Project: https://linux-test-project.github.io/
• Power ISA v3.1C: All books
• KVM Documentation: https://www.linux-kvm.org/
• SPEC Benchmarks: https://www.spec.org/

Appendix: Common Issues and Solutions

Issue: ISA Tests Failing

Debug approach:

1. Identify failing instruction
2. Run in simulation with waveform dump
3. Compare against ISA specification
4. Trace back to originating workstream
5. File bug with responsible team

Issue: Linux Kernel Panic

Debug approach:

1. Enable early printk
2. Identify panic location (PC address)
3. Check if ISA compliance tests covered this
4. Reproduce in simulation
5. Fix and retest

Issue: KVM Guest Crashes

Debug approach:

1. Check host kernel logs
2. Verify LPAR isolation
3. Test nested paging (radix-on-radix)
4. Simplify to single guest
5. Add debug instrumentation

Issue: Performance Below Target

Optimization approaches:

1. Profile with PMU
2. Identify hotspots
3. Optimize critical microarchitecture paths
4. Consider microcode optimizations
5. Balance features vs performance

Issues

Status: 24 open, 0 closed (0/24 complete)

Last updated: 2025-12-05 16:48:17