The device gate: Redmi 2f7cbe2e, reboot-clean, paired A/B in one thermal
window (arms interleaved, best-of-3 then best-of-2), rd12 + DirectGLES.
inproc vs spawn client CPU p50 7.880/7.889 vs 7.876/7.869 (-0.15%) and
7.987/7.989 vs 7.992/8.009 (+0.16%) - a tie inside the 0.2-4.2% within-
arm spread, sign flipping with arm order, recorded and not gated.
monolith is ~30% dearer. 22/22 runner exits clean, 44/44 PINNED, zero
Fatal.
The three mandatory numbers: socket doorbell vs condvar is a tie too -
client 121.1 waits/frame identical across transports, server 10 866-11
963 (inproc) vs 10 415-10 416 (spawn) waits/frame, and the contract's
'converting that into ~4 blocking reads may be cheaper' did not pay off;
the only column where the socket is worse is clipark/f (6.07 vs 5.60/5.75).
SEG_STAGE bytes/frame: 130.8 KB median / 8.01 MB steady (OpenRA), 816.2
KB / 1.53 MB (rd12). Records/frame post-chunking: 211/206 and 7 497/7
504. maxrec stays 1808 - the 8 MiB chunk budget is never reached. Both
framings reported throughout (the startup window runs ~7x the steady
state) rather than the flattering one.
MEASUREMENTS.md gains section 12 with the full protocol and tables; the
6.3 'no post-chunking distribution exists' gap now points there.
CURRENT_STAGE_PROGRESS.md marks gates 7/8 met and records the closeout
work plus two structural limits (spawn client windowed fields are zero
by construction - OnPresent runs in the server process - though its run
totals are valid stores; the stats dump is role-derived). ROADMAP marks
P6 closed in the stage table, the header and the milestone.
Evidence: notes/p6/gate7-device-ab.md, gate8-doorbell-device.md,
gate8-wire-counters.md, git-worktree-fix.md. check_doc_citations: 82
citations in the three documents, 0 problems.
ROADMAP gains the section "the immediate next item": a design, not an
implementation, for running the frontend on an x86_64 WSL process and the
backend on the Redmi over TCP, with the integration lane and the CI retrace
subset as the acceptance. The P6.5 row now points at it.
What the design rests on, verified in the tree: the control plane already
treats the rendezvous as a NAME with two ordered connections (SocketTransport),
ClientSession::StartOverSocket already separates "how the socket came" from the
handshake, MGPBlobRef addresses kSegStage only through one ResolveOrFatal, the
reply header and the event heads are already wire-shaped, LogLine exists in
CtrlMsg with no producer, goldens are shared between desktop and device, and
the trace APK can already exec libMobileGLServer.so from nativeLibraryDir.
What it does not rest on, stated rather than assumed: ILink is declared and
unused beyond LinkProgress, ShmLink does not exist, both sessions hold
SessionSegments directly - the lk seam body from the end-state review was never
built and is this wave's first package (lk2). The manifest has no INTERNET
permission.
The mechanism: StreamLink as mirrored private segments replicated by messages -
same sizes both ends, same offsets, so the codec, the watermark rules, the apply
thread and the encoder do not change; RingControl becomes Progress frames sent
on flush-on-idle (the recorded amendment to "appliedSeq is never lazy": late by
at most one flush, never early); replies become seq-stamped messages; the event
ring is mirrored with the P5e blocking rule intact. Cross-architecture makes
the PipeFields.def layout digest mandatory (wf). Server logs on another machine
make LogLine forwarding mandatory (lf) so the 34 server-log readers stay
unchanged. A --serve supervisor forks one child per session on the device,
started by a foreground Service in the trace APK.
Packages lk2 -> wf -> ct -> sl -> lf -> sv -> t65, each with red-once; the gate
list, the mandatory numbers (kWaitReply per frame x RTT, SEG_STAGE bytes/frame
against the link, PRESENT_CREDIT 1..3), the two-sided configuration runbook and
the risks (RTT per reply row, single large uploads, AP isolation) are in the
section. check_doc_citations: 74 citations, 0 problems.
The end state is re-ruled: client and server may sit on different machines,
OSes and architectures, joined over TCP. The AVF pVM / AF_VSOCK end state the
P6 end-state review assumed is withdrawn (retraction at its head, form D added
to its table, the vsock probe and both external unknowns struck).
The transport stack becomes two independently selectable axes, negotiated in
the handshake and mixable: control plane (ITransport: fork / unix:<path> /
tcp://host:port) and data plane (ILink: ShmLink / StreamLink). On one machine
control over TCP with data over shared segments is a legal pair; ShmLink brings
its own AF_UNIX aux rendezvous for SCM_RIGHTS, so ITransport narrows to control
frames. `auto` is decided by a successful segment delivery, never by inspecting
addresses, and a fall-back is named. Nothing above Transport/ may branch on the
link kind. ARCHITECTURE.md gains 11.9 for this; CONTRACT-P6.md gains 10.3.
ROADMAP: P6.5 and Ph get rows (both were referenced by the contract and absent
from the stage table); the IPC track becomes P6 -> P6.5 -> Ph -> P12 -> P9 ->
P10 -> P11(same-machine arm). Every later row is reconciled against the tree:
items already landed are struck (client vertex arrays, client-minted query
handles, credit default 1, SEG_EVENT overflow mechanism), the unreachable P7
gate (`nm | grep glslang` on a server image that IS libMobileGL.so) is replaced
by the 184-symbol ratchet share, fixed-width wire form moves from P7 to P6.5,
P12 is cut down per the review (server-owned display, no Surface passing), and
the debt table's stale claims are corrected: class C is down to two slots, not
15 and not 511; PACK-PBO and the 2 MiB reply cap are P9's, not P6's.
Verified against the tree and recorded honestly: the contract's three hs rows
(LinkTerms, Refuse, the fingerprint split) never landed - protocol.fbs has
neither - so CURRENT_STAGE_PROGRESS.md's claim that S6 ran red is withdrawn and
the rows move to P6.5; the 184-symbol ratchet gate does not exist in CI; the
server process never initialises PipeStats, so gate 8's `srv=0 srvpark=0` is a
structural zero (fix in progress in the tree, not in this commit).
check_doc_citations.py: 159 citations, one pre-existing basename ambiguity.
All ten P6 packages (a6/c6/lk/so/sm/cp/hs/dl/st/t6) are on feat/disaggregated
through 16bfab10. The two docs now say so honestly:
- ROADMAP.md (cumulative): the status line, the P6 stage row, and a new
milestone bullet record every package landed, exit-gate items 1-6 met, and
items 7 (device paired A/B in one thermal window) and 8 (the three mandatory
perf numbers) still pending -- so P6 is "implementation complete, exit
perf/device numbers pending", NOT closed.
- CURRENT_STAGE_PROGRESS.md: rewritten to hold ONLY the current stage. All
P5* history is gone (it lives in ROADMAP.md and the P5* reports); what
remains is P6's package table, the CONTRACT-P6 section-9 gate with each
item's honest status, the device results, the per-role log split, and the
explicitly-not-P6 list.
The shared control page both roles map had a mixed-writer cache line:
{appliedSeq, submittedSeq, retiredSeq, completedFrameSerial, presentAckSerial}
sat together, but submittedSeq is producer-written (Ring.h's "THE FIVE
WATERMARKS") while the other four are consumer-written. That is why no
single-writer progress block could be aliased over it, and it is what this
package fixes: submittedSeq moves up beside cmdHead, the other thing the
producer writes, and the four that remain become a named LinkProgress member -
the struct c6 declared in ILink.h - so a data plane with no shared page can own
the same four values and every wait predicate in SessionRings.h keeps ONE
implementation at source level.
The two event flags deliberately stay in the doorbell group. Promoting them
would put the client's per-drain exchange(0) on eventRingFull (EventRing.h:200)
onto the line the client's own spin predicate reads 1e5-1e6 times a frame.
73 call sites rewritten, 15 in the library and 58 in tests. The rewrite is
receiver-scoped rather than field-scoped, because SplitRuntimePeek.h:77 has its
own struct with a field of the same name and SplitRuntimePeek.cpp:146 has both
on one line - a field-scoped rename would have silently broken the peek struct
that MagmaRunAheadScenario reads nine times.
THE ASSERTS ARE THE PART THAT NEEDED A SECOND PASS. The first revision shipped
four aggregate asserts and an adversarial review broke them by counterexample:
swapping retiredSeq and completedFrameSerial inside LinkProgress compiled
clean, passed all four, and passed the runtime layout test too - because
appliedSeq stays at offset 0. Three wire-visible offsets on a shared page were
pinned by nothing. Nothing else in the tree covers it either: the ABI
fingerprint takes no input from this page, and sizeof(RingControl) is 4096
whatever the members do, because alignas(4096) makes it so.
So the block is now per-field as CONTRACT-P6 §8.3 actually asked, plus a
standard-layout precondition, a tail bound that alignas cannot satisfy for us,
and the LinkEventFlags mirror. Each was run red: the field swap reds the
per-field asserts by name, a fifth member inside LinkProgress reds sizeof.
One of them cannot go red, and Ring.h now says so rather than implying
otherwise. A SMALL member inserted between Progress and serverEpoch lands at
offset 288, inside Progress's own line, and serverEpoch's alignas(64) absorbs
up to 32 bytes of it - so both line asserts still pass. The review's proposed
fix does not catch it either; I tried it. A gate nobody can falsify is worse
than no gate, so the limit is written down beside the asserts.
Also: RingTest.ControlPageLayoutIsTheSharedContract said nothing about the one
field this package moved, and now asserts the producer/consumer separation and
the event flags' exclusion itself rather than borrowing the claim from Ring.h.
Ring.h grew 30 lines, so the Ring.h:NN citations this package and c6 authored
are re-anchored to named blocks instead of line numbers. ARCHITECTURE.md §11.2
is updated for the new layout, and a factual error introduced in the previous
revision of that paragraph - submittedSeq annotated as releasing staging, which
retiredSeq does - is corrected.
Gates: pull 0 added / 0 removed, .text size 10822147 unchanged; split 0/0,
.text size 11681395 unchanged; unit suite 2326/2328 with the same two
pre-existing environmental failures as the baseline. The five edits behind
MGITEST_SPLIT_RUNTIME_PEEK were proven compiled by a red-once, not assumed.
Note on the .text claim: that is a SIZE, not the bytes - field offsets moved,
so immediates moved with them. And this page's layout IS observable across
binaries; what is unobservable is behaviour within one binary. The contract
already books the layout change deliberately, before spawn exists to care.
CONTRACT-P6 §8.5 requires lk to publish its blast radius before it starts,
because an earlier draft's ratchet baseline was wrong by a factor of three and
a ratchet installed on the wrong number is red on its first CI run for reasons
that have nothing to do with a leak. The itemisation is mechanical, per file,
with the grep spelling stated: 250 seam-identifier references outside
Transport/ across 23 files (127 production, 123 test), and 44 member-access
sites that the regroup itself must rewrite, across 9 files - 17 of them in
MG_IntegrationTest, which is why lk builds with the integration tests ON.
The earlier build did not, and a missed edit there would have been green.
THE CORRECTION. Measuring that radius turned up a mistake in c6, landed two
commits ago. §8.3 and ILink.h both said lk should promote eventRingFull and
eventDropped into the watermark group and called the result single-writer.
eventRingFull has TWO writers: the server latches it with store(1) when
SEG_EVENT fills (EventRing.h:140) and the CLIENT clears it with an exchange(0)
on EVERY DRAIN (:200). Promoting it would put a per-drain read-modify-write by
the client on the same cache line as appliedSeq - which the server
release-stores every 64 records and the client's spin predicate reads 1e5-1e6
times a frame. That is new false sharing on the hottest line in the system,
and it would land in exactly the numbers this package's gate has to hold
constant. It is also the same class of error the earlier draft made with
submittedSeq, one field over.
So LinkProgress is now the four consumer-written watermarks and nothing else -
genuinely single-writer - and the two flags stay in the doorbell/generation
group, where mixed writers already live beside consumerParked/producerParked,
crossing the seam through a separate EventFlags() accessor on its own line.
The contract records the correction and its reasoning rather than quietly
restating the rule.
ALSO CORRECTED, from running the baseline suite: a6's link-experiment report
said the silently-empty build stamp had "no log and no gate to say so". That
is false. SessionHandshakeTest.cpp:140 asserts BuildStamp[0] != '\0' and :180
asserts that perturbing it changes the fingerprint, and BOTH GO RED in this
configuration right now - the worktree's .git holds a Windows path WSL's git
cannot resolve, so GIT_COMMIT_HASH_SHORT is "". The finding is therefore
stronger, not weaker: the gate that catches it already exists and is already
red. What is silent is the BUILD, and hs owes a named configure-time failure
rather than a new gate.
Baseline for lk, recorded: 3878 tests, two failures, both environmental and
understood - the fingerprint one above, and PipeCatalogue.FrontendNeverTakes-
AnApplierAddress, which walks up from cwd looking for MobileGL/MG_Impl and so
fails for any out-of-source build directory.
No behaviour change. The headers are still included by nothing.
c6 is P6's contract package. It lands CONTRACT-P6.md plus two headers and
changes nothing: no caller moves, no byte moves on any wire.
THE CONTRACT supersedes P6-CONTRACT-DRAFT.md, which was written before its own
audit and is wrong in four places - the ABI row, "the latch is implemented
unchanged", "cp is transport only", and "a transport swap and nothing else".
a6 measured all four. It carries 21 rulings, of which the load-bearing one is
D1: the spawned child keeps Transport == Spawn and anti-recursion becomes a
separate Dial axis. ARCHITECTURE.md:488's literal instruction is amended,
because 226 live lines test `Transport != Monolith` to select the SERVER arm
and forcing Monolith flips 148 MG_Backend lines to frontend glue in the one
process that has no frontend.
That ruling can be stated normatively without changing behaviour because of
something a6 found and the contract exploits: TransportMode::Spawn is
UNREACHABLE at this head. ConfigLoader.cpp:344 is the only writer for the
string "spawn" and it writes Monolith. So every rule conditioned on
Transport == Spawn constrains a state no process can enter - and the same fact
is why ConfigLoader's named refusal cannot currently falsify itself, which is
sm's to fix and §9.5's arm-proof gate to catch.
THE SEAM. ITransport says in its own header that the hot path bypasses it;
below it there was no interface of any kind, because Ring.h, ReplySlot.h and
EventRing.h each take a raw void* plus a capacity. ILink.h is that missing
thing. It is setup-time, not hot-path: no method is called per record or inside
a spin predicate, because Doorbell::Wait's predicate runs 1e5-1e6 times a frame
reading watermarks straight off the page, and because the only lane that could
measure a virtual there has four times the dispersion of the effect - a gate
that can only print "within noise" is ID-124 one level down.
StreamLink.h is declared and implemented by nobody, and that is its job: ILink's
adequacy is a claim only a compile can settle. Writing it forced three methods
the brief did not name - ResolveSpan, FlushProgress, and the reply pair - so it
has already earned its keep. Delete one ILink method it declares and the build
goes red.
Deliberately NOT here, each for a reason the contract records: Watermark::Reached
is not redefined (SessionRings.h owns it); Ring.cpp's reserve/pop bodies are not
relocated into a header that would then need the logger; RingControl is not
regrouped, because that rename is 109 production sites with five behind a
non-Android #if, so it is lk's with a published itemisation; and the schema rows
are specified but left to hs, because deprecating SurfaceReply.defaultFb while
appending `result` changes CreateSurfaceReply's arity and the existing
six-argument call would silently bind its defaultFb 0 to result.
INERTNESS IS STRUCTURAL, not measured. Zero object dependency files reference
either header, zero build rules do, and nothing in the tree includes them.
Verified anyway on both flavours: pull and split each have 0 symbols added,
0 removed, and .text byte-identical (10822147 / 11681395). check_doc_citations
resolves all 61 citations.
a6 is the read-only audit P6-SPAWN-PLAN puts first. Seven static items, each
produced by one auditor and re-resolved line by line by one adversarial
verifier; 198 rows, 65 of them contested, and only the surviving ones carry
into the report. Item 5 - can the server link without MG_Impl - is the one
experiment, and it is answered.
The headline is that P6's transport half is smaller than the plan assumed
(fc and fs really did land) and its process/role half is much larger. Four
statements in P6-SPAWN-PLAN / P6-CONTRACT-DRAFT are false at this head:
- `spawn` is not an observable state at all. ConfigLoader.cpp:339-346
recognises it and then writes Transport = Monolith, so "the child was
forced to monolith" and "the parent fell back" are the same value and
that named refusal cannot falsify itself. Meanwhile 226 live lines test
`Transport != Monolith` to select the SERVER arm, 148 of them in
MG_Backend - so ARCHITECTURE.md:488's rule, implemented literally, flips
the whole backend to frontend glue in the one process with no frontend.
- `cp` is not transport-only: the InitCapabilities REQUEST has no wire form,
and the codec refuses to encode the kind a live client still calls.
- the device-lost latch is not implemented; it was booked as carriage.
- the server cannot link without MG_Impl: 184 symbols, 177 of them real
function calls, owed 101 to P7 / 14 to P3b-P4b / 60 shared / 6 to P6.
There is also no module target to link, so the question could not have
been answered by editing a link line.
Four more blockers the earlier review missed: the apply thread aborts in
ConsumerDoorbell before popping its first record (contract 3.9's ruling, which
lk should retire rather than amend); neither side of the control plane is
wired to a socket; the control-reply wait has no deadline, so a frozen peer
wedges the GL thread inside eglMakeCurrent; and SurfaceReply cannot carry a
MobileGLResult, so a client cannot tell a dead server from a legitimate
refusal.
The abort census makes dl's funnel a redesign rather than a rename: 92 sites,
30 distinct family words against a 7-value wire enum, and three unbounded
peer-driven allocations with no try/catch anywhere under MG_Remote.
P6-ENDSTATE-REVIEW.md is the re-examination of P6 against the gfxstream-shaped
end state that produced a6's three added items. a6 overturned four of its own
claims - the MG_State eight's shape, the abort count, m_windowHandle's
injection points and a predicate name collision - and those are corrected in
place rather than left to be rediscovered.
Docs only. No code, no gate, no behaviour.
MEASUREMENTS 7.3 records what 82683d4a did, so the 30 s in that row stays as
written; a note under the table now says which value is live and where the
reason for the change is argued, so a reader looking up the barrier budget by
grep does not come away with the superseded number.
lavapipe/llvmpipe stall the apply thread for tens of seconds inside texture-handle
registration (vkCreateImageView -> lvp_CreateImageView -> llvmpipe_register_texture,
a JIT/futex path): one measured stall is 29.3-39.7 s and a whole inproc retrace run
accumulates ~44.6 s of it. At a 30 s bound those runs red intermittently on
Fatal{BarrierTimeout, "ResourceRespecify"} while the same stall under monolith is
merely slow - monolith has no cap on that path. Since the monolith shares the stall,
the bound, not the workload, was the defect.
kBarrierTimeoutMs becomes 120000, >3x the largest observed stall, which still leaves
the watchdog job: a record that is never retired still terminates the run and the
Fatal still names the seq. The comment now says deadlock detector rather than
performance gate and carries the measurement.
The fake-clock case that pins the budget moves with it: FenceWaitBudgetHonorsGl-
TimeoutAndFiniteTransportChunks expected 30000/30001/90000 and now expects
120000/120001/180000, so the assertion still pins the value instead of drifting.
Texts that wrote the old number down are updated: ARCHITECTURE 17.1, CONTRACT-P5E
2.4 (which now names kBarrierTimeoutMs rather than the literal), and the two
bring-up comments in PipeRoute.h / WireTables.cpp that dated a self-wait to
"thirty seconds".
Every place that stated "P5 does not chunk" as current behaviour except the
Fatal texts (previous commit) now records the stage chunk budget and what it
does not cover.
- CONTRACT-P5.md section 5: the STAGE_MB row names MGPipeStageChunkBytes() =
clamp(segment/4, 4096, segment), the two buffer walks (1e7c372e) and one
texture level's whole-width slabs (9469d48e, assembled by
StagedTextureStore::AdoptRun), and the Fatal that stays the backstop for a row
with no cut; the RING_MB row says the record bound is about the record's own
bytes.
- BRIEF-P5.md's R-10 section is no longer headed "does not chunk": it keeps the
record bound and the maxrec proof obligation unchanged and records that
content is cut, with the encoder Fatal as the fallback.
- ROADMAP.md's staging debt row and open question 11, ARCHITECTURE.md's
record-bound bullet and SEG_STAGE table note, README.md's knob row,
MEASUREMENTS.md section 6.3 and CURRENT_STAGE_PROGRESS.md's open item: the
explicit MOBILEGL_IPC_STAGE_MB=256 profile is no longer needed for the two cut
paths, and the carrier design for the rest stays P8.
- Historical results (notes/**/p5-results/, p5b/) are left exactly as recorded.
The twelve Server* forwarders' one-slot mailbox carried a raw function
pointer plus a void* to a stack-local Args struct (P5c audit row G4);
neither means anything across a process boundary. The slot now carries
one SurfaceControlFrame by value: kind is the op, scalars are the
arguments, and ok/eglMajor/eglMinor come back in the same value. The
blocking handshake, the shadow, the doorbell order and the C2 exit
block are unchanged.
- protocol.fbs: append-only - SurfaceOpKind gains SetSwapInterval=8,
ReleaseResources=9, SetWindowHandle=10; WindowKind gains MetalLayer=6;
SurfaceOp gains readSurface and context (the MakeCurrent four-tuple).
protocol_generated.h regenerated with the pinned flatc.
- Server/SurfaceControlFrame.{h,cpp}: the frame (trivially copyable by
static_assert) and the op enum - ten wire kinds plus four inproc-only
kinds (InitCapabilities is answered by CapsSnapshot on the wire,
SwapBuffers/InitWindowSurface have no production caller - f0-egl F8,
kept for the inproc test lane).
- Protocol/SurfaceOpCodec.{h,cpp}: the frame <-> SurfaceOp/SurfaceReply
codec, the explicit WindowBackend <-> WindowKind table, and the wire
entry ServerApplyWireSurfaceOp whose refusals are named:
Fatal{UnmigratedSurface, "AndroidNativeWindow@P12"} and
Fatal{ProtocolCorruption, "SurfaceOp"}.
- ServerLoop: RunOnApplyThread(fn, void*) -> RunSurfaceControlFrame(frame)
plus the dispatch ApplySurfaceControlFrame; the old per-forwarder Args
bodies moved into the dispatch unchanged (C7/ID-54, N-3, R-12 included).
RunProbeOnApplyThreadForTesting is the test seam through the same
channel (the hook lives in a member, never in the slot).
- Tests: RemoteClientTest/ServerLoopTest migrated to the probe seam; new
SurfaceControlFrameTest suite (mapping tables, wire round-trips, the
two named refusals) plus ServerLoopTest's AVoidForwarderCrossesAsOne-
DispatchedFrame (the frame channel's red-once handle) and
ServerLoopEglTest's TheInitializeDisplayReplyArrivesThroughTheFrame.
Statics, reverse channel, Magma cross-role sites, EGL control plane,
registry rekey, build/gate mechanics, the 15 BARRIER_PULLED fields'
carrier rulings, and the dual-block mechanism's design recon.
The section explained what gPipeInputs IS and what breaks under spawn, but not the one fact
that decides the shape of the fix, and not how a call actually reaches the driver through it.
Both are now in the document rather than only in the conversation that found them.
- THE POINTER FACT, now stated first because everything else follows from it: several
BARRIER_PULLED fields do not hold values, they hold pointers into client-owned objects.
PipeFill.cpp:274 fills m_textureUnitBase with `&ctx.GetTextureUnitObject(0)` - a raw base
into the frontend's array - and :245 fills m_programForDraw with a SharedPtr<ProgramObject>.
PipeInputs.h:669 dereferences it as `m_textureUnitBase[unit]`. PipeFill.cpp:2591-2592 says
the same of the shader-buffer field: "four raw bases into the frontend's binding-point
table".
The consequence gets its own paragraph in 1.4, because it is the step most likely to be got
wrong: this CANNOT be fixed by moving the block into shared memory. Mapping the same pages
into both processes does not make a client heap address meaningful in the server, and a
SharedPtr's refcount does not cross at all. The 15 fields each need a different SOURCE, not
a shared location.
- NEW 1.2, one draw end to end: glBindTexture marks a tracker bit and sends nothing, because
push only happens at a verb boundary; glDrawArrays enters MGPipeValidateForVerb
(PipeFill.cpp:3347) whose four steps are barrier decision, dirty walk, emission (records,
carrying handles), and the residual fill - which is where BARRIER_PULLED happens; the record
goes on SEG_CMD; the apply thread dispatches to the backend; PrepareForDraw reads either a
record-carried handle against the server's own tables, or gPipeInputs; then the real driver
call. Plus the field lifetime: stamped with verb N's serial, read during verb N's apply,
Fatal{UnmigratedPipeInput} if read at verb N+1 without a refill - one verb, never longer.
- The same example carries the Espryt/Magma split concretely: the texture binding reaches
Espryt as a record with a handle (P5e retired GetTextureUnitObject for it) and reaches Magma
through gPipeInputs into the client's array. That is FieldOwnership.def's own
"P5e (Espryt unbarriered), P7 (Magma)" made legible, and it is why section 2.1's table has
eight rows in that state.
Sections renumbered 1.1-1.4. Doc citation lint: 129 citations, 0 problems.
P6's premise is that it is "only a transport swap". That premise was bought by P5c and has
expired. Measured on this head, the two roles still share state directly, so a spawned server
would have no source for it. P5f is the phase that makes the premise true, and P6 does not
start before it.
WHAT THE MEASUREMENT FOUND
- FieldOwnership.def still carries 21 BARRIER_PULLED rows over 15 distinct fields. That class
is defined as "the server answers by reading a value the client's residual fill left in THE
SINGLE SHARED gPipeInputs while the verb barrier holds both threads apart". Eight of those
fields were retired by P5e for Espryt's unbarriered path only - Magma has not moved at all.
The strict lane measures 10 live <field>@<verb> pairs today.
- gPipeInputs (MG_Backend/MGPipe/PipeInputs.h:835) is a plain process global,
`inline PipeInputs& gPipeInputs = *new PipeInputs();` - not a shm segment. The client fills
it (MG_Impl/Pipe/PipeFill.cpp), the backend reads it. Under spawn the two processes have
DIFFERENT objects, the 15 BARRIER_PULLED fields have no filler in the server's copy, and
every read is Fatal{UnmigratedPipeInput}. MG_Impl is not in the server, so "let the server
fill it" is not available either. The header says this itself at :279 and :902.
- The twelve Server* EGL forwarders do not use the wire at all: they post a function pointer
plus a stack-local void* through a one-slot mailbox (ServerLoop.cpp:533-568, :645). The
SurfaceOp / SurfaceReply / WindowKind schema is defined in protocol.fbs and unused.
- Process-level statics with per-context semantics (g_syncedRenderStateParameters,
ScopedDefaultUnpackState::s_synced) - and the full list is unknown, because this defect class
is structurally invisible to inproc.
- MGPipeFrontendKeyedRegistryScope is still live at ~12 sites in DirectGLES.cpp, carrying
P3b/P4b's debt: the registry is still keyed by frontend address / lifetime id.
THE SCOPE RULE
P5f takes the cross-process-blocking subset of P3b/P4b/P7/P8/P9 and nothing else. One test:
does it still hold in another address space? No -> P5f. Yes but slow or ugly -> it stays with
the phase that owns it. So Magma's nine fields and its direct writes into client storage come
here; content-addressed CSO, internal shader baking and the fixed-width rewrite stay P7's. The
reverse channel's asynchrony and ordering stay P9's; only the parts that touch client memory
move. Class C is NOT P5f's - a named refusal behaves identically in two processes.
THE CENTRAL MECHANISM: A TWO-BLOCK REHEARSAL
P5c set the same rule (rule E) and checked it by AUDIT - a human reading 59 lines. P5f checks
it by MACHINE: give each role its own PipeInputs under inproc, and its own copy of every
per-context static, behind a knob. Anything that depends on the two being the same object
becomes Fatal{UnmigratedPipeInput, "<Field>@<Verb>"} with the field and verb named.
That rehearses the process split's SEMANTICS without a second process. It matters because
today "the server read the value the client filled" and "the server read the value a record
carried" are indistinguishable at runtime - which is exactly what P6 would discover on day
one. The package order puts the mechanism (f1) BEFORE the migrations deliberately: let the red
appear first and let it be the worklist, rather than having each package declare itself done
and then looking for a criterion.
Exit gate: the two-block lane green; strict-expected-markers.txt EMPTY with its two-sided
ratchet still armed; zero BARRIER_PULLED rows; rsp reading zero per frame; Magma judged by the
same criteria as Espryt. The negative control is that turning the two-block knob OFF must move
at least one named case from green to red - otherwise the mechanism proves nothing, which is
ID-122's lesson.
ALSO IN THIS COMMIT
- ROADMAP gains the P5f row and the IPC track becomes P5e -> P5f -> P6; P6's status cell
becomes "blocked on P5f".
- README and CURRENT_STAGE_PROGRESS gain the same, plus the file-map entry.
- Both P6 documents gain a blocked banner naming what is not true yet.
Doc citation lint: 124 citations across docs/Disaggregated/*.md, 0 problems.
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