Refactor: make the DFX collectors resident across runs - #2126
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📝 WalkthroughWalkthroughChangesResident collector lifecycle
Estimated code review effort: 4 (Complex) | ~60 minutes Merge Risk: 🟡 Moderate · up to Diagnostic runs using a smaller topology can write beyond collector shared-memory bounds during reset, risking corrupted diagnostics or worker instability. This should be fixed before merge. Poem
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In `@src/common/platform/shared/host/args_dump_collector.cpp`:
- Around line 98-104: Prevent begin_run() reset loops from accessing beyond
allocated shared-memory state arrays: either allocate every region for
PLATFORM_MAX_AICPU_THREADS or bound each loop by its corresponding requested
count. Apply the same correction in
src/common/platform/shared/host/args_dump_collector.cpp:98-104,
src/a2a3/platform/shared/host/pmu_collector.cpp:311-317, and
src/a5/platform/shared/host/pmu_collector.cpp:343-350; update the
direct-accessor reset paths consistently.
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📒 Files selected for processing (23)
src/a2a3/platform/include/host/pmu_collector.hsrc/a2a3/platform/onboard/host/device_runner.cppsrc/a2a3/platform/shared/host/pmu_collector.cppsrc/a2a3/platform/sim/host/device_runner.cppsrc/a5/platform/include/host/pmu_collector.hsrc/a5/platform/onboard/host/device_runner.cppsrc/a5/platform/shared/host/pmu_collector.cppsrc/a5/platform/sim/host/device_runner.cppsrc/common/platform/include/host/args_dump_collector.hsrc/common/platform/include/host/chip_swimlane_collector.hsrc/common/platform/include/host/dep_gen_collector.hsrc/common/platform/include/host/profiler_base.hsrc/common/platform/include/host/scope_stats_collector.hsrc/common/platform/onboard/host/device_runner_base.cppsrc/common/platform/onboard/host/device_runner_base.hsrc/common/platform/shared/host/args_dump_collector.cppsrc/common/platform/shared/host/chip_swimlane_collector.cppsrc/common/platform/shared/host/dep_gen_collector.cppsrc/common/platform/shared/host/scope_stats_collector.cppsrc/common/platform/sim/host/device_runner_base.htests/st/a2a3/tensormap_and_ringbuffer/dfx/residency/test_collector_residency.pytests/ut/cpp/common/test_args_dump_collector.cpptests/ut/cpp/common/test_pmu_collector.cpp
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The five host-side DFX collectors were worker-level objects with run-level resource lifetime: every run initialized them, started their threads, and finalized them again. They now initialize once per worker and are released at finalize_device, so a worker that runs repeatedly no longer rebuilds five shared-memory regions and their thread sets on each run. Three parts of the collectors depended on that per-run rebuild. Draining. stop() guaranteed the two queue levels were drained by joining the threads that consume them — joining mgmt proved its final sweep landed, joining the collector shards proved the shards were consumed. quiesce() supplies the same guarantee through a two-phase epoch handshake, so the threads observe the run boundary and survive it. start() is idempotent for the same reason init() is: otherwise each run appends another full set of threads to the same collector. Per-run state. initialize() cleared it as a byproduct of allocating a fresh region, so each collector takes a begin_run() that binds the run's artifact configuration and drops everything describing a single run. That includes the device-side record counters, which are the easiest half to miss: the AICPU never resets them, they are documented as monotonic, and reconcile compares the host's collected count against them — so a carried counter makes dep_gen skip its export entirely. Each reset is a narrow write_range_to_device over adjacent counters rather than a bulk write-back, so it cannot race the AICPU-owned fields sharing their cache line, and each loop is bounded by the count its region was allocated for: the args_dump and pmu regions are sized from the requested thread and core counts, so a platform-maximum loop would write past their ends. The swimlane region is the exception that needs no such bound, being sized at the compile-time maximum its offsets already derive from. Pool topology. Buffer seeding covers pools [0, aicpu_thread_num), and a core's recycled lane is (core / CORES_PER_BLOCKDIM) % aicpu_thread_num, so a collector's pools are shaped for the core and AICPU-thread counts of the run that built them. The runners latch those counts and rebuild the collectors when a later run differs; scene tests sharing a directory share a worker and do vary aicpu_thread_num. The pool-array offsets stay a compile-time constant, so this changes no host/device sizing contract. tests/st/a2a3/tensormap_and_ringbuffer/dfx/residency covers both failure modes. It drives Worker.run twice at one shape and once at another, bypassing the --rounds path that disables every diagnostic — which is why "one worker, several runs, DFX on" occurs nowhere else in the suite. Both failures are silent and produce wrong artifacts rather than errors, so the assertions are specific: the runs are sequential, so each run's swimlane records must start after the previous run's last record ends, and every run's deps.json must be complete on its own. Reverting either fix makes the corresponding assertion fail. The pmu and args_dump C++ unit tests follow the renamed entry point.
This was referenced Sep 5, 2026
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Summary
The five host-side DFX collectors were worker-level objects with run-level resource lifetime: every run initialized them, started their threads, and finalized them again. They now initialize once per worker and are released at
finalize_device, so a worker that runs repeatedly no longer rebuilds five shared-memory regions and their thread sets on each run.Part of #2078.
Three parts of the collectors depended on that per-run rebuild, and each had to be handled for residency to be correct.
Draining.
stop()guaranteed the two queue levels were drained by joining the threads that consume them — joining mgmt proved its final sweep landed, joining the collector shards proved the shards were consumed.quiesce()supplies the same guarantee through a two-phase epoch handshake, so the threads observe the run boundary and survive it.start()becomes idempotent for the same reasoninit()is: otherwise each run appends another full set of threads to the same collector.Per-run state.
initialize()cleared it as a byproduct of allocating a fresh region, so each collector now takes abegin_run()that binds the run's artifact configuration and drops everything describing a single run. That includes the device-side record counters, the easiest half to miss: the AICPU never resets them, they are documented as monotonic, and reconcile compares the host's collected count against them — so a carried counter makes dep_gen skip its export entirely. Each reset is a narrowwrite_range_to_deviceover adjacent counters rather than a bulk write-back, so it cannot race the AICPU-owned fields sharing their cache line.Pool topology. Buffer seeding covers pools
[0, aicpu_thread_num), and a core's recycled lane is(core / CORES_PER_BLOCKDIM) % aicpu_thread_num, so a collector's pools are shaped for the core and AICPU-thread counts of the run that built them. The runners latch those counts and rebuild the collectors when a later run differs — scene tests sharing a directory share a worker and do varyaicpu_thread_num. The pool-array offsets stay a compile-time constant (#2107), so this changes no host/device sizing contract.Testing
tests/st/a2a3/tensormap_and_ringbuffer/dfx/residencycovers both failure modes. It drivesWorker.runtwice at one shape and once at another, bypassing the--roundspath that disables every diagnostic — which is why "one worker, several runs, DFX on" occurs nowhere else in the suite. It lives on a2a3 because that is the arch with a host-map path, where a leakedhalHostRegistermapping fails the next run at rc=8.Both failures are silent and produce wrong artifacts rather than errors, so the assertions are specific rather than "non-empty":
deps.jsonmust be complete on its own.Both were confirmed to be load-bearing by reverting each fix in turn:
run 1's records start at …, which is not after run 0's last record end …— run 1 re-exported run 0's records verbatim (same count, same content)deps.jsonentirely — reconcile failed and the export was skippedGate run on
upstream/main@4e4d3a4ad+ this commit:task-submit): all 7 channels including residencya5simsweep — passa2a3simsweep — 44 passed; the one failure (TestSpmdPagedAttentionHighPerf::b4_h32_kv8_s512_bs128_fp16,max_diff=0.0625) is pre-existing, reproduced identically on a clean base build, and ismanual-only so the per-PR lane deselects ittests/linthooks, ruff, pyrightThe pmu and args_dump C++ unit tests follow the renamed entry point.