refactor(dfx): unify L2 phase buffer switching

[vegetabledoww]

Summary

• Reuse DeviceProfilerEngine for sched/orch phase buffer switching and recovery.
• Centralize free-queue ownership, head updates, and sequence bookkeeping.
• Keep phase startup acquisition non-blocking through try_pop_free().
• Clarify task/phase/AICore wrapper naming.
• Add unit tests for buffer switching, replacement failure, recovery, and empty startup queues.
• Preserve the reserved sequence number when recovering after a replacement-pop failure.

Fixes #1385

Validation

• test_profiler_device_engine: passed
• a2a3 AICPU kernel: built successfully
• a5 AICPU kernel: built successfully
• pre-commit checks: passed

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📝 Walkthrough

Walkthrough

DeviceProfilerEngine now centralizes free-buffer claiming and adds non-blocking startup acquisition. The L2 swimlane collector uses typed contexts and engine-based phase-buffer operations, with new unit tests covering queue transitions and empty-queue behavior.

Changes

Device profiler buffer flow

Layer / File(s)	Summary
Free-buffer claiming and acquisition src/common/platform/include/aicpu/profiler_device_engine.h	Free-slot ownership transfer is centralized in claim_free; try_pop_free adds non-blocking acquisition, while pop_free retains blocking behavior.
L2 swimlane buffer integration src/common/platform/shared/aicpu/l2_swimlane_collector_aicpu.cpp	Typed device-module contexts route phase priming, recovery, switching, and pending AICore publication through DeviceProfilerEngine.
Engine behavior tests and build wiring tests/ut/cpp/CMakeLists.txt, tests/ut/cpp/common/test_profiler_device_engine.cpp	Adds the unit-test target, fake module, and coverage for switching, replacement failure, free pops, and empty startup queues.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Collector as L2SwimlaneCollector
  participant Engine as DeviceProfilerEngine
  participant FreeQueue
  participant ReadyQueue
  Collector->>Engine: prime or recover phase buffer
  Engine->>FreeQueue: claim free slot
  Collector->>Engine: switch full buffer
  Engine->>ReadyQueue: enqueue completed buffer
  Engine->>FreeQueue: pop replacement buffer

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Possibly related PRs

• hw-native-sys/simpler#1276: Migrates L2Swimlane and related AICPU profilers onto DeviceProfilerEngine.
• hw-native-sys/simpler#1313: Updates DeviceProfilerEngine free-queue waiting and backpressure behavior.

Poem

A rabbit found a free-slot ring,
And taught the buffers how to spring.
“Try” hops lightly, “pop” waits true,
Phase lanes bloom in sched and orch too.
Tests twitch their noses: all paths go through!

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 9.62% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	❓ Inconclusive	No meaningful pull request description was provided to assess against the code changes.	Add a short description of the change and its purpose so reviewers can verify it matches the patch.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly matches the main refactor to unify L2 phase buffer switching.

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[gemini-code-assist]

Code Review

This pull request refactors the DeviceProfilerEngine to extract buffer claiming logic and introduces a non-blocking try_pop_free method. It also templatizes and refactors the L2 swimlane collector to use this unified engine for buffer management, switching, and recovery, replacing manual queue operations. Additionally, unit tests are added for the profiler device engine. A bug was identified in acquire_phase_slot where recovering a phase buffer after a switch failure causes a sequence number gap because state->head.current_buf_seq + 1 is passed instead of state->head.current_buf_seq.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/common/platform/shared/aicpu/l2_swimlane_collector_aicpu.cpp`:
- Around line 887-890: The recovery path in L2SwimlaneDeviceModule should reuse
the current buffer sequence instead of advancing it: update pop_free() in
src/common/platform/shared/aicpu/l2_swimlane_collector_aicpu.cpp:887-890 to pass
state->head.current_buf_seq. Update the corresponding test in
tests/ut/cpp/common/test_profiler_device_engine.cpp:138-154 to pass the existing
sequence and assert that it remains 8.

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Fix all unresolved CodeRabbit comments on this PR:

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• Create a new PR with the fixes

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Configuration used: Organization UI

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Run ID: 10ec047d-7f7f-4bc9-b367-921432992124

📥 Commits

Reviewing files that changed from the base of the PR and between 6e910df and 936b457.

📒 Files selected for processing (4)

• src/common/platform/include/aicpu/profiler_device_engine.h
• src/common/platform/shared/aicpu/l2_swimlane_collector_aicpu.cpp
• tests/ut/cpp/CMakeLists.txt
• tests/ut/cpp/common/test_profiler_device_engine.cpp