Per user direction: feature-gating is appropriate for per-step diagnostic
logging (real perf/memory cost) but the name should be specific to the
mechanism, not a generic "diag-log" catch-all. kernel-step-trace
describes what the feature provides — per-step records written to the
ring by kernels.
Pure rename, no behavioral changes. Touched: Cargo.toml feature decl,
lib.rs cfg attribute, perception.rs (~25 cfg attributes including
not(feature) pairs), gpu_log.rs + smoothness_lambda_controller.cu doc
comments, gpu_log_ring_invariants.rs file-level cfg + ignore-attribute
text.
Atomic refactor wiring the GPU log ring's first producer end-to-end:
- cuda/gpu_log_helpers.cuh (new): extract LogHeader/LogRecord/LogRing
struct definitions + the log_record() device __forceinline__ helper
into a shared header. Single source of truth — other kernels include
this rather than redefining the structs.
- cuda/gpu_log_ring.cu: refactor to include gpu_log_helpers.cuh; retain
only the gpu_log_tick kernel.
- cuda/smoothness_lambda_controller.cu: include gpu_log_helpers.cuh, add
trailing (LogRing*, const int*) args, capture pre-EMA jitter +
post-EMA jitter + target + excess_ratio into shared mem, and emit
three records per call (RT_INPUT, RT_STATE, RT_OUTPUT) gated on
non-null ring pointer.
- trainer/perception.rs: feature-gated (cuda-diag-log) ring allocation +
step counter (mapped-pinned host shadow), gpu_log_tick launch FIRST
inside the captured graph, two new pointer args on the smoothness
controller launch (null when feature off), step-counter DtoD shadow
alongside the other telemetry shadows, drain task spawn (skipped when
no tokio runtime — sync tests still construct the trainer), and a
feature-gated Drop impl that aborts the drain task on shutdown.
- tests/smoothness_lambda_controller_invariants.rs: pass null pointers
for the two new kernel args; the kernel's nullptr guard preserves
pre-existing behaviour.
- build.rs: rerun-if-changed on cuda/gpu_log_ids.h and
cuda/gpu_log_helpers.cuh so header edits trigger cubin rebuilds.
Verified: cargo build / check --all-targets clean both with and without
the cuda-diag-log feature; 4/4 smoothness controller invariant tests
pass; 9/9 perception_overfit integration tests pass under the feature.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
