Fourteen axes drive the attention subsystem from the grid: the diffusers
method, the sdp override chain, the dispatcher kernel, five sdnq attention
knobs and six sparse settings. An axis writes shared.opts.data and rebuilds
the chain itself, since the onchange for these settings runs through the
queue lock a grid cell already holds. SharedSettingsStackHelper saves and
restores every attention setting around the grid, keys an axis introduced
included, and an axis for a setting a backend owns warns when that backend
is not in the active chain.
The sdnq backend read six settings on every call; it now captures them
when the chain is built. Each backend declares the settings its call
captures, and webui registers one onchange over those names plus the
override set and the torch kernel flags, so a change rebuilds the chain
between jobs. When a compiled model is resident the rebuild also resets
dynamo, since its graphs hold the previous router.
SD_ATTN_DEBUG logs each distinct route once: backend, component role,
step, shapes, dtype and mask presence. The router takes an optional
observer for it, so the clean path carries one pointer check. report()
returns the active chain and generation context, and torch_info records
the whole chain as one string instead of the last prepared backend.
A module-level context tells attention consumers what is running: the
component role (transformer, text encoder, vae), the index of the
denoiser forward about to run, the pass length, and the model. It is
opened and closed around process_images, reset per denoising pass beside
the callback setup, and advanced by both step sources: the classic
callback passes the completed step plus one, the modular pre-forward
hook counts forwards. Roles come from the existing text encoder and vae
hijacks and the modular phase hooks. The step also lives in a device
scalar updated in place, so a compiled reader keeps its graph across
steps.
Replace the six closure hijacks stacked in devices.set_sdpa_params with
a registry of declarative backends and one router installed in their
place. Each backend declares the constraints its closure carried as a
predicate, a priority matching its old stacking position, and a prepare
step that imports and configures the implementation; the router walks
the prepared entries by priority and hands declined calls to the
terminal backend (dynamic, flex) or the original sdpa, so fallback is
the router's job rather than each closure's.
- parity held: gates transcribed literally, the same kernel kwargs,
enable_gqa passed to the original only when set, torch_info keeps the
last prepared backend, the dynamic pin still set
- a backend enabled on a platform without it warns instead of silently
doing nothing
- the legacy set_* entry points are gone; devices.py installs the router
- test/test-attention-router.py checks every override subset against the
old stacking order, gate parity over 16,000 shape cases, dispatch,
terminal handoff and prepare isolation, offline
modules/attention.py becomes modules/attention/: hijacks.py keeps the six
sdpa monkeypatch setters, dispatcher.py the diffusers-side processor and
dispatcher setup with the kernels hub hijack, and the package facade
re-exports every public name so call sites are unchanged. The devices
import moves inside set_diffusers_attention, which removes the
devices <-> attention import cycle.
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