Per user directive: htod/dtod transfers on the training hot path that
bounce through pageable host memory are a top-priority cleanup target.
Pinned memory (cuMemHostAlloc) + memcpy_htod_async enables DMA + stream
overlap. The codebase already has the pattern (size_pinned,
rng_step_pinned in gpu_replay_buffer.rs) — extend it to every per-step
transfer.
Prompt changes:
- New PINMEM category in §3 table (severity 5)
- Scan command excludes tests/benches/examples/smoke_tests
- New §6 learned pattern entry with 3-tier fix hierarchy:
(1) eliminate via on-device compute → (2) stage through pinned →
(3) async for dtod
- Added PINMEM to category ID allowlist in §2
Scoreboard seed: 10 initial findings from an iter-9 scan. Top-scoring:
PINMEM-003 (scratch_f32 scalar, E=1, score=25) and PINMEM-004 (init
scalars, score=15). Hot-path candidates include NoisyNet epsilon
refresh, PER replay-buffer inserts, target-net sync, PPO rollout.
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