Breaks the one process = one server = one session = one context equation
that the whole stack's correctness used to rest on. Design and per-slice
shape: docs/Disaggregated/design/11-state-ownership.md.
S1 wire: bind_context ring record (opcode 84) announces the current
context at the make-current edge; CreateContext/DestroyContext join the
SurfaceOp control frames; control revision 5 -> 6; the server keeps a
per-session token table and refuses unknown tokens by name.
S2 server: SessionRuntime per session with thread-scoped resolution
(singletons become fallbacks), per-thread gPipeInputs, per-session latch
domains, per-thread segment resolvers; the in-process unix supervisor
serves up to MOBILEGL_IPC_INPROC_MAX_SESSIONS (16) concurrent sessions;
surface mode is declared per session and the display lease refuses a
second on-screen session by name.
S3 frontend: ShareGroupState owns the shared object stores and name
generators (buffer/texture/renderbuffer/sampler/program), GLContext keeps
per-context bindings/errors/container objects; pGLContext becomes
thread-local with a process default context preserving the single-context
world verbatim; eglCreateContext builds a real GLContext and joins the
sharing context's group.
S4 backend: native EGL tuples keyed by (session, context token);
InitDisplayAndContext's unconditional teardown is gone - creating a
second context or surface no longer destroys the first; eglCreateContext
sharing is wired to the native driver; bind_context is the native switch
point.
S5 applier: MGPipeApplierState splits into MGPipeObjectRecords (per
share group) and MGPipeWorkingState (per context), resolved through a
{session, token} registry with a thread-local cached fast path.
Tests: MultiSessionTest (incl. two sessions x two contexts interleaved
with real clear/readback witnesses), ApplierOwnershipTest (with a
null-resolver negative control), ContextStateOwnershipTest,
ServerLoopEglTest native-context liveness; 99/99 of the acceptance set
green on the host build.
Known debts (documented in the design doc): twin registries still keyed
by handle alone, no per-record ContextSlot, process-global backend
generations, MakeCurrent dedup per current binding.
The spawn work had the two roles append to one MOBILEGL_LOG_FILE_PATH under
O_APPEND. It was correct - two processes at one offset would corrupt the file,
O_APPEND made each write atomic - but it put two sessions' lines in one place
and made every per-side assertion a search. This splits the sink: the client
role writes <base>.client.log and the server role writes <base>.server.log.
THE BASE NAME NAMES NO FILE ANY MORE, AND THAT IS THE POINT. Leaving the
client at the old unsuffixed path would have been the compatible choice and the
wrong one: a reader that was not updated would go on finding a file, go on
passing, and go on seeing only half the session - and a refusal census that
reports a confident zero for the half it cannot see is worse than one that
fails. With both names moved, an un-updated reader gets "file not found" and
says so. There were 34 such readers; every one is moved here.
THE ROLE IS PER-THREAD, not per-process, because under inproc both roles are
threads of one process. Log.cpp keys the sink on a thread-local role: the apply
thread declares itself server (ServerLoop.cpp), a spawned image is server for
its whole life (MOBILEGL_IPC_ROLE=server, read once), and everything else is
the client. The naming rule (RoleLogPath) and the two whole-log operations
(ReadRoleLogs / TruncateRoleLogs) are EXPORTED from the library, so no reader
reimplements the derivation - a second copy is the copy that falls behind.
Readers, by how they read:
- unit mains set MOBILEGL_LOG_FILE_PATH and read a role file: they keep the
base in the env and derive the client path from the library helper.
- the death-test child runners (ReadLog) now concatenate BOTH roles: a death
test asserts the CHILD said something, and the applier's refusals - the very
diagnostics these check - are written under the server role.
- the offset-based Emit readers derive the client path once after setenv.
- PipeStatsWindow reads both, because draws/vbs increment in the backend's
PrepareForDraw - the apply thread, the server role - so the summary line is
in the server file even under inproc.
- run_trace_case.cmake's split census reads both files; the client keeps the
transport markers.
- split_log_paths.py (and its self-test, and the control stub) derive both
role files from the declared base.
- the Android script pulls both role files off the device and concatenates
them, so every downstream check is unchanged - and it judges a role file by
CONTENT, because `run-as test -f` through `exec-out` returned 0 for a missing
file on the device and `exec-out` folds cat's own not-found line into stdout.
The monolith arm legitimately has no server file, and that is a silent skip
rather than a one-line server log.
Guarded so a pull build is untouched: RoleLogPath and the role sink are wholly
inside MOBILEGL_BUILD_DISAGGREGATED; a non-disaggregated build writes the base
path exactly as before. G1 re-measured - 0 symbol diff, .text unchanged at
0xa52203.
Verified on device 2f7cbe2e: monolith writes only the client log (no phantom
server log), inproc and spawn each write both and pass their transport proofs
(spawn: server role in pid 16125). Unit 2353 (one pre-existing environmental
failure), integration-split 186/186, integration-spawn 102/102, retrace 6/6,
control smoke 12/12, split-log-paths self-test 9/9.
- ImageEmit.TheThreeAccessConstantsArePinnedOnBothSidesOfTheWire: ruling 16 / ID-94 is
that the encode and the decode are ONE table, so the case reaches both halves - the
numbers, MGPipeEncodeImageAccess, MGPipeDecodeImageAccess, the validity predicate and
the two read/write predicates - and then round-trips all three GL tokens through a
real glBindImageTexture so what is pinned is the byte that actually crosses. The
drift it catches (1 <-> 2) is a `writeonly` image the shader can read back, which no
pixel test on a lockstep tree could see while the frontend value was answering.
- FramebufferEmit.TheRecordsElevenSurfacesAreTheWholePointSetTheServerReads: the server
twin of AnAttachmentPointAboveTheWireWidthIsRefusedNotTruncated. P5e spends that
refusal as a licence - the by-handle attachment walk iterates Color[0..7] + Depth +
Stencil instead of the frontend's 41 points - so both halves are pinned: a
fully-populated framebuffer round-trips every point into the applier's record, and a
point above the width leaves the record the server holds completely unmoved (hash and
FramebufferSerial), rather than merely counting a refusal.
- FramebufferEmit.ADefaultFramebufferResizeReEmitsTheRecordWithItsNewExtent: ruling 15,
which S3 flagged as unsettled and said was load-bearing because under run-ahead there
is no other extent source. The case drives the surface-changed consumer's own call -
AllocateStorage on the attachment at the new extent, no rebind, no re-attach - which
is exactly the shape the framebuffer shutter would have suppressed.
- All three get their pull-build skip twin through the suites' X-macro lists (G2/G14).
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