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.
It was one case on one backend under one transport: OpenRA, DirectGLES,
inproc. It is now every CI case, both backends, inproc AND spawn - 154 CI
entries, 156 local ctest entries - because every defect the spawn work turned
up was a question about the SERVER's process and not about any one trace or
either backend.
THE DirectVulkan ARM. tools/trace_replay/CMakeLists.txt carried "a
DirectVulkan arm would be measuring a server nobody has written yet". True
when P5 wrote it; false since P5f/P7 landed Magma's server consumers and its
run-ahead readiness gate. Leaving it would have shipped a split shape whose
second backend nothing ever ran - the same class of hole as a lane that runs
monolith under a name that says split. Magma now brings up a server process
of its own and OpenRA retraces across it at ssim=1.000000, which is only
possible because this branch also taught the child to load its config: before
that, a DirectVulkan session brought up a DirectGLES server and the two
halves disagreed about which backend the capability mask describes.
`split` BECOMES AN OPT-OUT. It began as an opt-in naming one case, because
one case was the work. Marking 39 cases `"split": true` would carry no
information and would reinstate the hole the key was written to close, only
mirrored: a case added later would get the monolith arms and be silently
absent from the split ones, and absent is the one state nothing reds on. A CI
case is now in the subset unless it says `"split": false`, which is a
reviewable claim that a trace cannot cross a role boundary.
THE CI MATRIX GAINS A THIRD DIMENSION. The job took {backend, case} and
hard-coded MOBILEGL_TRANSPORT=inproc in its own run block, so `spawn` had no
way into CI at all; the .SPAWN ctest entries existed only for a local build.
It is {backend, case, transport} now, the backends are the case's own
ci_backends rather than a hard-coded DirectGLES, and the artifact names carry
the transport or the two arms of one {backend, case} would overwrite each
other's uploads.
inproc STAYS AS THE CONTROL. Same library, same codec, same applier, same
picture; the only difference is which process the server role runs in.
Running only spawn would leave "did the transport break it?" and "did the
phase break it?" answerable only together - which is the question every
failure in this phase has turned on, including the SIGSEGV that D1 explained.
BOTH NEGATIVE CONTROLS FOLLOW THE ARM. retrace_pull_library_control.sh and
retrace_drop_draw_control.sh each exported MOBILEGL_TRANSPORT=inproc
themselves, so on a spawn job they would have gone on proving something about
the other arm while spawn ran unguarded. They read SPLIT_TRANSPORT now, and
default to inproc so a caller that sets nothing behaves exactly as before.
scripts/ci/control_smoke_test.sh: 22 passed, 0 failed against the stubbed
ctest, including the two modes that matter most - a red whose SSIM never fell
and a knob that armed and dropped nothing.
The spawn arm needs a second binary and the inproc arm needs none, so the job
places libMobileGLServer.so only on the spawn arm and a missing one is a
named failure there rather than a LaunchServer refusal 78 jobs deep.
Measured locally as this lands: 39 of the 78 SPAWN entries complete, all
green. The rest are still running.
swung0x48