Curiosity stores params/grads/Adam state as 4 non-contiguous sub-buffers
(w1, b1, w2, b2 — each its own CudaSlice<f32>). The single-pointer kernel
signature couldn't describe them. The first fix-up wired 4 of 5 aux
groups; Curiosity (group 7) was deferred.
This commit extends the param_group_oracle kernel to accept a sub-buffer
table (mapped-pinned u64 ptr-arrays + i32 counts), with `n_sub=1` for
groups 0-6 (existing behavior) and `n_sub=4` for Curiosity. Pass A/B/C
(p99 histograms) iterate sub-buffers via a new
`sp4_histogram_p99_multi<BLOCK_SIZE>` template that mirrors the original
three-pass structure but loops sub-buffers within the max-reduce + binning
passes; Pass 3 (cumulative-from-top) divides by `total_count`. Pass D
(4-way reduce) iterates sub-buffers in the accumulator loop; Pass E
(L1 trunk only) reads `grads_ptrs[0]` (group 0 has n_sub=1 by construction).
`Sp4ParamGroupBufs` redefined from a flat quartet to `Vec<Sp4SubBuffer>`.
Convenience constructors `Sp4ParamGroupBufs::single(...)` and
`Sp4ParamGroupBufs::empty()` keep call sites ergonomic; `total_count()`
for kernel arg. Switched Copy → Clone since the descriptor now owns a Vec.
`SP4AuxBuffers` extended with `curiosity` field (5-tuple from 4-tuple).
Added 16 public accessors to GpuCuriosityTrainer (grad + Adam state) and
8 to CuriosityWeightSet (weights + lengths) for the 4 sub-buffers ×
4 signal types.
`oracle_subbuf_table_buf: MappedU64Buffer` (4×4 = 16 u64s) and
`oracle_subbuf_counts_buf: MappedI32Buffer` (4 i32s) allocated at
construction. Launcher overwrites entries [0..n_sub) per group launch
via volatile writes; zeros the unused tail (defence-in-depth so a kernel
bug reading past `n_sub` lands on count=0 no-op). Inter-launch
`stream.synchronize()` added so the next iteration's host writes don't
race with the in-flight kernel's coalesced loads from the persistent
table. Cold-path producer; per-launch sync cost is negligible vs the
kernel work.
`build_sp4_aux_buffers` signature changed: takes
`Option<&CuriosityWeightSet>` and `Option<&GpuCuriosityTrainer>` since
Curiosity state lives outside FusedTrainingCtx (owned by
GpuExperienceCollector). Layer B's training-loop caller threads them
in from `collector.curiosity_weight_set()` + the collector's
`curiosity_trainer` field; both must be Some together (caller
responsibility — they live on the same collector). Passing None for
either yields an empty curiosity descriptor and the launcher silently
skips group 7.
`param_group_buffers` return type changed from
`Option<(u64, u64, u64, u64, usize, i32, i32)>` to
`Option<(Sp4ParamGroupBufs, i32, i32)>`. All groups now return Some(...)
(Curiosity included); None reserved for forward-compat.
GPU test extended: group 7 exercises 4 sub-buffers of distinct shapes
[1024, 32, 1024, 32] (w1/b1/w2/b2-like sizes scaled to keep test runtime
small while still exercising the multi-sub-buffer iteration), each with
its own seed offset so distinct sub-buffers have distinct distributions
— catches buffer-mixup bugs in the kernel's sub-buffer iteration.
Reference computation builds union vectors and computes p99/WD_RATE
over the union. Test launcher refactored to `&[TestSubBuffer]` slice
matching the production kernel's table-packing layout.
All 8 SP4 param-groups now produce real outputs in Layer A. The
launcher's `count == 0` short-circuit retained for the optional aux-
trainer fallback (init failures on gpu_iqn / gpu_attention / curiosity).
`MappedU64Buffer` gained a manual Debug impl (warn missing_debug_impls)
for parity with MappedU32Buffer.
cargo check -p ml --lib --tests clean. Workspace clean. Layer B can now
safely consume all 8 ISV[WEIGHT_BOUND/ADAM_M_BOUND/ADAM_V_BOUND/WD_RATE[group]]
slots.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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