MobileGL/docs/archive/notes/p5b/BRIEF-P5B.md

BRIEF-P5B — verb migration under inproc, Minecraft-first

Goal, one sentence: fully separate-thread rendering of REAL workloads as fast as possible — every Minecraft trace, and the four A/B trace cases, rendered by the apply thread under MOBILEGL_TRANSPORT=inproc — by migrating the class-C slots the census measured, in the order it measured them, with the inproc lane's abort count and the traces' first-blocker list as the only gates (ID-66, ID-68).

Read PACKAGE-PREAMBLE.md first, then MobileGL/MG_Remote/CONTRACT-P5B.md (the wire contract, every row of it), then this file.

1. What c0b landed (head p5b/c0b, see p5b-results/c0b-v1.md)

Every package compiles and links on day one against real headers:

• the wire rows: draw_vbo grew kDrawIsIndirect + the MGPDrawIndirect second tail; five rows appended at opcodes 72..76 (bind_shader_image, patch_parameter, bind_stream_output, set_storage_block_binding, copy_framebuffer_to_texture); MGPCopyRegion grew its two GL names; the clear discriminants have one spelling in MGPipeTypes.h;
• the codec: encode/decode arms for every row, tail cross-checks, the name blob;
• WireVerbSink has one method per row (13 new + the widened OnDrawVbo), and ServerVerbSink overrides every one with a Fatal{UnmigratedVerb, "<GL slot>"} stub;
• the client emit table's class-C list is PARTITIONED per package (MGR_UNMIGRATED_{D1,I1,T2,F1,TAIL}_SLOTS, kEmittedSlots{D1,I1,T2,F1}, ownership static_asserts 19 / 7 / 7 / 11 / 20) so four packages edit four disjoint regions;
• the stamp rows (FieldOwnership.def), the generated tables, the pinned counts, and a round-trip unit case per row in PipeWireCodecTest.cpp.

2. The four packages

Each package owns its slots, its list and count in EmitTables.cpp, its stub bodies in PipeApplier.cpp, and its cases in PipeWireCodecTest.cpp + the integration lane. CONTRACT-P5B §2 gives every slot's record fields, sink dispatch and refusal names; §8 the two pre-granted edits to c0b's files.

package	measured slots (census entries)	companions (same rows, owned too)	rows	model
d1 — indexed / instanced / multi-draw / indirect	DrawElements 56 (+ every Minecraft trace), MultiDrawElementsBaseVertex 18, DrawArraysInstancedBaseInstance 4, DrawElementsBaseVertex 4, MultiDrawArrays 2, MultiDrawElements 2, DrawArraysInstanced 2, MultiDrawElementsIndirect 2, MultiDrawArraysIndirectCount 2, DrawElementsInstancedBaseVertex (trace)	DrawElementsInstanced, DrawElementsInstancedBaseInstance, DrawElementsInstancedBaseVertexBaseInstance, DrawRangeElements, DrawRangeElementsBaseVertex, MultiDrawArraysIndirect, MultiDrawElementsIndirectCount, DrawArraysIndirect, DrawElementsIndirect	draw_vbo (59)	Claude, premium
i1 — image / compute / barrier / copy-image / storage block	BindImageTexture 138, DispatchCompute 49, CopyImageSubData 30, MemoryBarrier 18, ShaderStorageBlockBinding 4	DispatchComputeIndirect, MemoryBarrierByRegion	bind_shader_image (72), launch_grid (60), memory_barrier (61), resource_copy_region (53), set_storage_block_binding (75)	Claude
t2 — XFB spans, XFB object bind, patch parameter	BeginTransformFeedback 95, PatchParameteri 43, BindTransformFeedback 2	EndTransformFeedback, PauseTransformFeedback, ResumeTransformFeedback, (DeleteTransformFeedback: no row, see contract)	begin/end/pause/resume_stream_output (62..65), bind_stream_output (74), patch_parameter (73)	Claude
f1 — clears, framebuffer-sourced copies, mips	ClearBufferiv 12, ClearBufferuiv 8, ClearBufferfv 6, ClearBufferfi 1, ClearNamedFramebufferfv 2, CopyTexImage2D 3, GenerateMipmap 2	ClearNamedFramebufferfi/iv/uiv, CopyTexSubImage2D	clear (57), copy_framebuffer_to_texture (76), generate_mipmap (54)	codex astra — additive and mechanical

Per slot the work is the same three edits: the emitter (class C → B in EmitTables.cpp, the pre-verb hook order kept), the ServerVerbSink body (the backend call the contract names), and a lane case that proves the record crossed. Nothing in the backends, unless the contract names the site (i1's mirror skip, f1's optional mip-storage re-derivation) - and then only behind #if MOBILEGL_BUILD_DISAGGREGATED.

3. The per-package gate

• the inproc lane's abort count for your slots → 0, and each affected scenario reaches its NEXT first blocker, reported by name (Fatal{UnmigratedVerb, "…"}, Fatal{UnmigratedEmulation, "…"}, or a wrong-answer failure - whichever comes first). Run ~/w7/p5b-c0b-census.sh <your tree> <outdir> and diff results.json against c0b's baseline (~/w7/p5b-c0b-census-logs/results.json: 432 passed / 185 skipped / 505 aborted / 27 failed, all 505 aborts UnmigratedVerb, the per-slot table identical to census-classC.md's).
• d1 additionally: every Minecraft trace reaches its next first blocker under inproc, reported by name per fixture (the census's trace table), via the same per-entry private-log method as p6_census_traces.{sh,py}; a trace that RENDERS is reported with its SSIM.
• the integrator's quick gate: unit lanes green (c0b's baseline + yours), integration-split inproc 22/22, push integration-gpu 1128/1128 name-for-name, G1 0/0/0/0 .text +0.
• no reviews between rounds; one codex review at P5b's close.

4. File ownership

file	owner in P5b	others
MG_Pipe/MGPipeTypes.h, PipeCalls.def, PipeFields.def, FieldOwnership.def, Coverage.def, FillPoints.def, scripts/gen_pipe*.py, MG_Remote/CONTRACT-P5B.md	c0b / integrator	t2: kCapBackendOwnsXfbCapture (contract §6.5); i1: the GetProgramForDispatch row (§6.9). Anything else: ask.
MG_Remote/Wire/PipeWireCodec.{h,cpp}	w1's file; c0b landed the arms	a package edits the layout arm of ITS row only, with the integrator
MG_Remote/Server/PipeApplier.{h,cpp}	v1's file	each package replaces ITS stub bodies (the // ---- d1/i1/t2/f1 ---- blocks) and may add ITS tallies
MG_Remote/Client/EmitTables.{h,cpp}	c1's file	each package edits ITS MGR_UNMIGRATED_*_SLOTS, ITS kEmittedSlots*, ITS emitters
MG_Remote/Client/SlotCaps.h	c1's file	t2: the EndTransformFeedback probe → kCapBackendOwnsXfbCapture
MG_Test/Wire/PipeWireCodecTest.cpp, MG_Test/Wire/RemoteClientTest.cpp	shared	append your cases below c0b's; the partition pins (UnmigratedSlotCount() etc.) move with your counts
MG_IntegrationTest/**	t1's file	each package adds ITS lane cases / scenario arms
MG_Backend/DirectGLES/**, MG_Backend/DirectVulkan/**	untouched by c0b	only the sites the contract names, only behind #if MOBILEGL_BUILD_DISAGGREGATED
~/w7/notes/p5b/p5b-results/<slug>-v1.md	you

5. The loop that follows

1. The four packages land, each on its own gate. The integrator merges in landing order, regenerates (gen_pipe.py, gen_pipe_field_ownership.py - never hand-merge generated/), runs the quick gate.
2. Re-census on the merged head: the lane (p5b-c0b-census.sh) and the traces. The new first-blocker table is the next round's package list, same shape, same gates.
3. Migrate the new first blockers (wave 3's tail is P9/P10-shaped: readbacks, queries, syncs) and the residual-input debts rsp points at where a verb's pull is what blocks it.
4. Repeat until the four A/B trace cases render under inproc on the Redmi. That is P5b's exit; P6's spawn transport follows (ID-68).