MobileGL/docs/Disaggregated/notes/perf-p15/HANDOFF.md

P15 handoff (living document)

The plan and its measurements are in PLAN-P15.md; the audit is in PARITY-AUDIT.md.

Target (PLAN §0.1, revised by the user 2026-10-08):

• CPU scenes: FCL presenting-thread CPU at or below dev monolith (Magma <= 1.79, Espryt <= 2.14 ms/frame), dev measured in the same session, ~5 % noise.
• GPU scene (Iris + BSL): fps within ~5 % of MobileGlues on both backends.

RESUME HERE (2026-10-09 evening, end of the long P15 run)

Rules from the user (2026-10-09):

• A fresh agent per clear task boundary.
• Mechanical jobs (bench A/Bs that follow the existing scripts, builds, log/profile parsing, CI watching) go to sonnet/haiku subagents. Design and implementation stay on opus.
• No minSdk raise for the shipped build: API 29 is a SEPARATE artifact (its own library, plugin APK and FCL-embedded copy).
• No record bypass: monolith = record arm.
• No emulated-TLS work below 29: b-i/b-ii/b-iii are dropped; native TLS at 29 is the TLS answer.
• No new Android API usage. Keep MobileGL platform-agnostic unless a platform path is measured and has no portable alternative.
• ASurfaceControl, frame-rate hints and ADPF are deferred.

Where the code is (worktree .claude/worktrees/p15, branch p15impl):

• origin/feat/disaggregated = db346f28 plus the pushes listed in SCOREBOARD.
• Local on p15impl, not pushed:
  • 14d63881, docs.
  • 8d548d5b, window-scoped freqcheck.
  • ca0a3b74, a cherry-pick of the coordinator's LTO commit 190580f2 on build-opt. The coordinator pushes 190580f2, so drop ca0a3b74 when rebasing.
  • a0015bad, Magma 2a + 2b. Its message carries the m2ab result, or says it is pending.
• wip/espryt-depthcopy-measured (the two Espryt BSL GPU items rebased onto origin 9f610167, with the device numbers in its message; the old wip/espryt-depthcopy eb7572ff is the unmeasured original). Measured 2026-10-09 on device, NOT landed: no gain on BSL. x = with both items, b = without, both LTO builds of origin 9f610167; gpuhunt, 3 VALID reps each, one arm per cooldown:
  • BSL: x 51.4 fps (0.921 of MobileGlues 55.8), b 51.9 (0.930); GPU 100 % busy in all runs, GPU 19.45 vs 19.29 ms/frame (MobileGlues 17.88). The target of 0.95 is not reached; the items are neutral.
  • Vanilla cpuhunt check (Espryt monolith): x 248.5 fps / 2.87 ms GL CPU, b 254.0 / 2.83 (-2.2 % fps, within noise; no CPU regression worth the name, but no gain).
  • Engaged: the simpleperf profile of the BSL render thread shows BlitDepthTexture2D 0.100 ms/frame in b and gone in x; FramebufferImpl::SyncToBackendByHandle 0.178 -> 0.162. The saved CPU is hidden by the GPU-bound frame, and the GPU time per frame did not move, so the Espryt BSL gap is not in these items. See SCOREBOARD (ebbsl). Original description:
  • (1) Depth glCopyImageSubData goes to the driver (ES 3.2 / EXT/OES_copy_image), with the scratch-FBO depth blit as fallback. Knob MOBILEGL_ESPRYT_NATIVE_DEPTH_COPY.
  • (2) A per-point attachment shadow on the Espryt FBO twin skips an attach call for a point that already holds the same surface. It is keyed on the surface handle {slot, gen} plus driver id, level, layer, call and re-mint generation; texture-side syncs still run. Knob MOBILEGL_ESPRYT_ATTACHMENT_SHADOW.
  • Tests: DepthCopyImageScenario (2 cases) and AttachmentReattachScenario (4 cases), both registered on the split arms. Red-once: a shifted native copy fails all DepthCopyImage cases on DirectGLES; dropping Level from the shadow key fails the level case; keying on the driver id alone fails the recycled-name case.
  • Host suites: 1672 DirectGLES ctest entries (monolith + Split) pass serially in WSL (362 skipped by design), including DepthCopyImage, AttachmentReattach, PassOrder and every blit case.
• wip/api29-switch (42922d21, on p15impl): -Pmobilegl.androidApi=29 in build.gradle and the plugin's build.gradle.kts.
  • It sets minSdk 29 and therefore ANDROID_PLATFORM android-29; the plugin gets the .api29 id suffix and -api29 version suffix. The CMake API-guard comment is updated. Default stays 26.
  • Verified: the API 29 lib has 95 R_AARCH64_TLSDESC relocs and a TLS segment. __emutls remains only for 3 libc++abi variables.
  • No A/B yet. The next agent runs the H2 A/B: API 26 vs 29, monolith + inproc, both backends, MobileGlues control.
  • Nothing in the tree needs a compile-time API gate yet, so none was added.
  • The FCL-embedded 29 copy needs a matching FCL-side switch (FCL's own minSdk).

The m2ab device job was still running at hand-off. Do not interrupt it.

• What it is:

  • Started as a background chain: bash p15/m2ab_job.sh > p15/runs/m2ab_job.out; bash p15/espg_job.sh.
  • espg_job.sh is parked: it only echoes "espg parked". The real Espryt BSL job is espg_job.sh.next.
  • m2ab_job waits for the device lock, cools to battery ≤ 33.0 °C, then runs PROFILE=cpuhunt devjob2.sh p15/runs/m2ab.log bash p15/m2ab_session.sh.

• Arms: cpuhunt H2, 3 interleaved reps, PF=1. Both libs are LTO builds of the same tree:

  • n = libs/p15en, without 2a/2b; monolith with sp=1, plus inproc;
  • e = libs/p15e, with 2a/2b (it also carries the Espryt items, which do nothing on Magma); monolith with sp=1, plus inproc;
  • MobileGlues.

• Results:

  • per run in p15/runs/m2ab/<arm>-r<N>/ (fps.txt, valid.txt, perf.data on sp=1 runs);
  • the summary is appended to p15/runs/m2ab.log (look for the n= lines).

• Device restore: the session script runs fcl_scene.sh restore and fcl_p14.sh restore, and devjob2's exit trap stops the bench session and releases the lock.

• Interim at hand-off (GL CPU ms/frame):

  arm	n (without 2a/2b)	e (with 2a/2b)
  monolith r1 / r2	2.39 / 2.48	2.29 / 2.45
  inproc GL thread	1.20 / 1.20	1.17
  inproc fps	343.5 / 371.6	363.8

• When it ends:

  1. Summarize with fclsum.py runs/m2ab. Judge 2a/2b on monolith GL CPU and on the inproc apply thread (threads.txt mgl-srv-apply).
  2. Build the profile caches offline: prof_prep_offline.sh <run> p15e|p15en runs/c1c2/x-DirectVulkan-r1. Compare RenameBusyWireStore, VkBufferObject::Create, SweepDeferredWireReleases and IsSubmitIndexComplete.
  3. If neutral-or-better: amend a0015bad's message with the numbers. Push the p15impl commits WITHOUT ca0a3b74, i.e. cherry-pick onto origin after the coordinator pushes 190580f2. Then CI.

• Host suites for 2a/2b: done and at baseline (92 environment unit failures, 2 ColdStart).

  • The one extra unit failure seen once, CompositorRecovery.ACompositorOnTheServerWindowRecovers..., is a pre-existing load flake: under full CPU load it fails 6/20 without the change and 2/20 with it.

LTO and the server check (coordinator):

• libMobileGLServer.so is built and packaged by the LTO-ON assemblePluginRelease. Its only libMobileGL import, mobilegl_server_main, is exported by the LTO lib.
• The spawn-transport smoke was NOT run. It needs the LTO-ON plugin APK (libs/p15lto/plugin.apk) installed, because the FCL mgdebug install has no libMobileGLServer.so.

Open items, in order:

1. CI fix: the reds of Test run 37925410578 on db346f28 (integration-split-strict, the two DirectVulkan retrace reds, skip census). Then push the LTO commit (190580f2 on build-opt) and the local p15impl commits (without ca0a3b74), and confirm CI is green.
2. userguide/ at the repo root, an end-user guide for every setup: which setup to use, how to build, integrate and run it. Covers:
   • Android FCL-embedded;
   • the plugin APK (inproc, spawn with MOBILEGL_IPC_SURFACE=server, TCP);
   • the API 26 and API 29 artifacts;
   • Linux/anland;
   • the Windows WGL drop-in;
   • build options, user-facing knobs and troubleshooting.
3. DONE 2026-10-09: Espryt BSL GPU items (wip/espryt-depthcopy-measured): device A/B measured, no gain, not landed (see above and SCOREBOARD ebbsl). The Espryt BSL gap to MobileGlues (0.92) is still open; the next lead is the GPU side (render-stage trace of Espryt vs MobileGlues passes), not driver calls.
4. Small CPU batch: ValidateForVerb residue, Tracker::Update (0.018, mostly inherent), EmitGlobalConstants (0.026). Expected ≤0.03 ms in total.
   • DONE on host, branch cpubatch (2026-10-09). Device measurement pending. Line-level profile of fbm2 h-r1..r3 (both backends, p15h syms) and m2ab e-DirectVulkan r1..r3 (LTO).
   • EmitGlobalConstants, cut: the (ShaderCso, Version) key is per handle (the applier keeps one block per record), so switching back to a program whose uniforms did not move sends nothing, and a moved one sends a span against its own held image instead of the whole block. The span is the range the frontend wrote (ProgramObject::MarkUBOContentDirtyRange / TakeUBODirtyRange), so the client shadow and its two-ended diff scan are gone. The scan plus shadow copies were ~0.0065 ms/frame; with the skipped switch-back sends, expect ~0.007-0.010 ms/frame.
   • Tracker::Update: inherent, skipped. ~30 ns per verb over ~25 frontend counters; the only real cut is the epoch skip (PLAN stage 1), which is not a small item.
   • ValidateForVerb residue: skipped. The largest named piece (~0.008 ms/frame) is the MOBILEGL_PIPE_POISON stamp walk, armed by MOBILEGL_BUILD_DISAGGREGATED. The bench libraries are the plugin build (split ON); the FCL-embedded build (split OFF, INFO) compiles it out. The rest (prologue, singleton guards, gates) is spread below 0.002 each.
5. API 29 build plus its A/B (wip/api29-switch).
6. Smaller follow-ups:

   • DONE 2026-10-09: bench_session.sh stop now runs pin_clocks.sh restore first (verified over a 17-session run: max clocks back to stock after every session, daemons running, no session file). The scratchpad devjob2.sh / fcl_bench.sh hard-code the p15 worktree's copy of the harness; point them at a tree that has this commit.

   • The Fatal{UnmigratedSurface, "AndroidNativeWindow@P12"} text and the tests asserting on it still point at P12. The rule is permanent: a client window cannot cross processes, so windowed spawn uses MOBILEGL_IPC_SURFACE=server. Reword the message to say that.

   • DONE 2026-10-09: the windowed out-of-process smoke of the LTO plugin APK passes on both backends. The plugin is debug-signed and replaced the installed one, with the user's OK. Setup:

     • server: the plugin's MobileGLDisplayActivity, i.e. the :mglwin in-process server on tcp://127.0.0.1:40613;
     • client: FCL with MOBILEGL_TRANSPORT=spawn, MOBILEGL_IPC_CONTROL=tcp://127.0.0.1:40613 and MOBILEGL_IPC_SURFACE=server. ServerOwned 1280x800 window, Espryt and Magma both in-world.

     A plain spawned child has no display (NoServerDisplay). Evidence is in the coordinator scratchpad, p15/runs/spawn_smoke2/.

   • Open from that run: every run logs MG_Remote server: shared image 1 could not be sent on the aux socket (rc=3). Rendering continues, apparently on the non-zero-copy fallback. Find out why the loopback-TCP aux-socket send fails.

Harness rules (all in scratchpad p15/; the tools live in tools/device_bench/disagg/):

• H2 = fcl_bench.sh, driven by fclab2.sh for interleaved arms; summaries come from fclsum.py.

• Every session goes through devjob2.sh (device lock, bench session, restore on exit). Profiles:

  • PROFILE=cpuhunt for CPU work (CPU 1.5/1.25 GHz, GPU 903);
  • PROFILE=gpuhunt for BSL (CPU 2.4/1.8, GPU 578).

• BSL: one arm per cooldown (battery ≤ 33.0 °C between runs), arms interleaved across cooldowns. At gpuhunt the scene hits thermal limits by the second back-to-back rep.

• Validity: freqcheck.py judges clocks over the measurement windows only (measure_raw.txt spans) and thermal over the whole run.

• Stop a session on thr>0, a thermal_pwrlevel below the pin, or "max capped". Discard INVALID runs and go on. Never stop on tpl alone: it is 6 by construction at gpuhunt.

• Build simpleperf binary caches only after a session, or offline with prof_prep_offline.sh (donor cache plus the build-id entry in build_id_list). Never adb-pull during a session.

• Never edit a bash script that a running job will still read (bash reads scripts incrementally).

• TaskStop does not reliably kill child bash processes on this host: kill the PIDs, and only the inner session processes, so devjob's cleanup runs.

• Libraries live in scratchpad/p15/libs/<tag>/lib/arm64-v8a/libMobileGL.so, with symbols in syms/<tag>/ and runs in runs/<session>/. Tags:

  tag	contents
  p15e	LTO + 2a/2b + Espryt items
  p15en	p15e without 2a/2b
  p15lto / p15off	LTO ON / OFF, both with 2a/2b
  p15a29	API 29
  p15h	the pipe batch
  p15y	1c
  p15t	before 1c

• Profile tools: topinc.py, callers.py, callees.py, layerfns.py, layerdiff.py, diffprof.py, appside.py, pftstate.py (Perfetto SQL), threadstate.py.

Device state at hand-off:

• At hand-off the m2ab session was still running; it restores FCL, the scene and the bench session itself.
• The device lock is released by devjob2 when m2ab ends.
• The plugin installs top.mobilegl.plugin.*.trace from earlier phases are still on the device.

Earlier (2026-10-09): cuts 1b + 1c, cut 4, pipe-record pieces

• Landed locally (pushed after the BSL gpuhunt check):
  • 66e3b2c1 (rebased as 65d4b808): Espryt surface-size memo, GL CPU 3.18 -> 3.05.
  • 533a2564: Magma deferred clears (1c) plus coalesced pass-begin barriers (1b).
    • Per frame: passes 11.5 -> 4.3 (dev 4.1), barriers 15.5 -> 9.0 (dev 3.4).
    • Inproc +5.0 % fps, apply thread -0.17 ms; monolith GL CPU -0.09 ms.
• Landed 2026-10-09 afternoon:
  • 485dff14: pipe client batch, i.e. the per-framebuffer FB-state memo (MOBILEGL_PIPE_FRAMEBUFFER_STATE_MEMO), handle hints, per-buffer handle reuse and the per-verb gate cache.
  • c85c9439: Magma hash TLS hoist.
  • Effect: H2 GL CPU Magma 2.68 -> 2.62, Espryt 3.03 -> 3.00. The profile is in SCOREBOARD (fbm2).
  • 9eed5a27 / 9ff97c2e: CI branch fixes. The E1 control follows ApplierReset, and ScenarioIsolation is listed as unarmed in verify-split.
• Small-cut policy: pieces below about 0.03 ms are verified by their own before/after function profile plus a red-once, and get one H2 A/B per batch.
• Order (coordinator, 2026-10-09): FB-state memo, then handle cache on objects, vertex input, program, samplers, accessor/TLS hoist, the ValidateForVerb dirty walk, Tracker.
  • No record-bypass design change until the user decides.
• Parked: the Espryt attrib-format split (MONOLITH-DIFF.md).
• Remaining Magma barriers: CPU ceiling ≤0.02 ms. Revisit only if BSL shows a Magma GPU gap.
• Harness gotchas found today:
  • tpl in the freq sampler is kgsl thermal_pwrlevel. Under gpuhunt it is 6 by construction (the 578 MHz pin); freqcheck already maps it. Stop a session on INVALID or thr > 0, never on tpl > 0.
  • Never run binary_cache_builder (adb pulls) while a session is measuring. Build binary caches after the session ends.
  • FCL sometimes dies at bootstrap with signal 34 (seen on every build including MobileGlues); fclab2 retries, and a run that never reaches the world is lost.
• Monolith floor estimate (MONOLITH-DIFF.md, structural):
  • Pipe record: 0.35 -> about 0.10-0.13 if every local piece lands.
  • Whole Magma GL thread: about 2.35-2.40 ms (native TLS: about 2.30), against dev 2.00.

Earlier (2026-10-08 late): harness H2, dev reference, scoreboard

• Every FCL vanilla number now goes in SCOREBOARD.md. It has one row per session, as fps ratio to MobileGlues plus CPU ms/frame. It also holds the fixed dev reference, so "vs dev" no longer needs dev in every session. The per-function dev baseline is in MONOLITH-DIFF.md.
• The old probe's variance was core placement. The scheduler gave MobileGL's monolith render thread the X4 core 72-90 % of the time and MobileGlues' 47-60 %. MobileGlues' fps tracked its X4 share (fifi: 60 % -> 378, 47 % -> 344).
• Harness H2 (scratchpad p15/fcl_bench.sh, fclab2.sh, benchwin.py): the same for every arm.
  • After world entry, taskset -a -p 7c pins FCL to cpu2-6 (A720).
  • fps comes from the SurfaceView BLAST layer frame= in dumpsys SurfaceFlinger. It agrees with the MobileGL fps log over the same span (252.1 vs ~253).
  • Warmup: 20 s, then 5 s windows until two consecutive ones agree within 3 %.
  • Measurement: two 5 s windows with no tracer; CPU from schedstat.
  • atrace, then the optional simpleperf (sp=1), run only after the windows.
• Frozen bench saves (1.21.5 and 1.21.4-Fabric, scratchpad p15/freeze_world.py):
  • Rules: no daylight, weather or mob-spawn cycle, randomTickSpeed 0, no fire tick.
  • DayTime 6000, clear weather.
  • Before this, the vanilla save's day cycle was running.
  • The originals are on the device as level.dat.p15-orig.
• Spread over 3 interleaved reps, (max - min) / mean:
  • Old probe: Espryt 9.3 %, Magma 5.6 %, MobileGlues 1.3 %; MobileGlues spanned 322-376 across sessions.
  • H2: Espryt 1.2 %, Magma 2.9 %, MobileGlues 2.0 %, dev 6-7 %.
• Dev reference (H2, safter, all VALID): MobileGlues 321.5 fps / 1.70 ms. dev Magma is 0.950 of that (2.01 ms) and dev Espryt 0.887 (2.38 ms).
• On A720 the monolith gap is larger than the X4 hid: p15s Magma is 0.768 of MobileGlues (0.81 of dev, 2.91 ms) and Espryt 0.746 (0.84 of dev, 3.18 ms). That is +0.90 / +0.80 ms/frame of CPU over dev.
• Inproc p15s Magma on H2: 327.7 fps against MobileGlues ~321.
• Emulated TLS: __emutls_get_address costs ~0.06 ms/frame of self time on the p15 monolith render thread, spread over many callers. dev shows almost none. The structural fix is native TLS (minSdk), which is the user's call.

Earlier (2026-10-08, after S0)

Every number below carries its profile and passed the validity check (state.txt). cpuhunt = CPU about 1.5/1.25 GHz, GPU 903 MHz (cleanly CPU-bound); interval 0, anland off, daemons stopped.

• The S0 milestone's absolute numbers are superseded. The perf stack's msm_performance caps (787 / 1286 / 1075 / 1248 MHz) were clamping the CPU under the pin for some of that session. Only same-session deltas from it stand. Measurement now uses bench_session.sh and the sampler (PLAN §1), and the probe reports only clean fps windows taken before any tracing (P15PROBE trace-start marker, 25 s settle).

• FCL vanilla 1.21.5, cpuhunt, presenting-thread CPU ms/frame:

  build	Espryt	Magma
  dev	1.76	1.60
  p15k (S0 + VAO shadow)	2.10	2.03
  p15l (+ vertex-elements dedup)	2.10	2.08

  MobileGlues: 1.58 in an earlier cpuhunt session (needs a same-session re-run with clean windows). Floor gap: Espryt +0.34, Magma +0.43 ms.

• Driver-call redundancy:

  • Measured with a diagnostic build that counts every host GLES/EGL call and redundant re-sets (p15diag worktree, never committed; HostCount.inl and VkCount.cpp).
  • Espryt sent 3717 host calls/frame against MC's ~874: 2118 glDisableVertexAttribArray, 378 enable, 378 divisor, all re-sets.
  • Two fixes, each independently removes the walk churn:
    • b4e209e1: a shadow of each driver VAO (850 calls/frame);
    • c8a5abe5: the client no longer re-creates an identical vertex-elements record on every glBindVertexBuffer. With the shadow off it takes 3724 down to 1228.
  • CPU gain is small (about 0.1 ms): the calls were cheap in the driver.
  • Magma issues about 380 Vulkan calls/frame with essentially none redundant.

• Where Espryt's gap to dev is now: the driver time equals dev's (0.50 vs 0.48). The excess is libMobileGL itself, 0.75 vs 0.32: client half 0.51, backend 0.24, applier 0.02. The client half is spread thin (validate, tracker, emitters, residual copy): S1's draw-delta.

• Inproc (cpuhunt):

  • Espryt reaches 306 fps vs MobileGlues about 319; GL thread 1.68 ms, apply thread 1.83 ms of a 3.27 ms frame.
  • Neither thread is saturated. The apply thread waits in queueBuffer on a GPU fence (present pacing), and the GL thread waits on the apply thread.
  • MOBILEGL_IPC_PRESENT_CREDIT=2 changes nothing (300 fps).
  • Beating MobileGlues on inproc needs a present-path change (stage P territory, dropped by the user), not CPU work.

• S0b: the fixture minecraft-1.21.5-vanilla-fcl-in-world is landed (4e27342e) and is in the SSIM gate as fcl (32/32 on p15j).

• Knobs on FCL: adb shell setprop debug.mobilegl.env "MOBILEGL_A=1;MOBILEGL_B=0" (49c6394d); fclab.sh takes a 6th field K=V,K=V.

• MC's AFK frame limit: inactivityFpsLimit:"afk" (MC 1.21.2+) made later probe windows and profiles spin in System.nanoTime. fcl_scene.sh now sets "minimized" for bench scenes and restores the original options files (/data/local/tmp/p15-opts-121{5,4}.txt). Profiles taken before this are partly AFK-polluted.

• BSL at gpuhunt (CPU 2380/1689 MHz, GPU 578 MHz, all 100 % GPU busy):

  • MobileGlues 53.4 fps;
  • dev Magma 53.2;
  • p15l Magma 51.8 (3 reps, -3.0 % vs MobileGlues: target met, -2.6 % vs dev to bisect);
  • Espryt dev and p15l 48.3 (-9.6 %): the GPU gap, inherited from dev.

• Same-session cpuhunt, apply thread:

  build	fps	apply ms/frame
  MobileGlues	329	CPU 1.55
  Magma inproc p15m	300	1.6
  Espryt inproc	296	1.65-1.8

  • Inproc beats MobileGlues only when the apply thread's CPU is below MobileGlues' (both pay the same queueBuffer wait). About 0.3 ms per frame beyond the apply CPU is still unexplained.
  • 500b63ea: per-store reuse of renamed-away wire buffers (Magma apply -0.13 ms).
  • ONE_TIME_SUBMIT: no effect (A/B'd, knob dropped).
  • Magma's driver work is about 2x dev's: vkResetCommandBuffer 0.09 + vkEndCommandBuffer 0.11 ms/frame.

• Inproc serialization found (2026-10-08, p15l cpuhunt profiles): every blit reached the client as BlitNamedFramebuffer, a verb with no MGP_VERB_OP_LIST row, so ClientVerbIsBarriered answered barriered and the GL thread quiesced the applier once per frame (1.65 ms/frame parked in WaitForApplyToCatchUp, plus 0.11 from the following glBindTexture). The apply thread then idled 0.24 ms parked plus 0.2 ms spinning in Doorbell::Wait. e00db8e6 replaces the inverse and its barriered fallback with a verb -> record-op table (MG_Pipe/VerbRecordOps.h, one row per verb by static_assert; no knob, user decision).

  • Same-session blab (cpuhunt): Magma inproc 319.6 -> 334.9 fps (+4.8 %), Espryt inproc 324.4 -> 338.1 (+4.2 %).
  • Wait census (MOBILEGL_IPC_WAIT_STATS=1, 7acf3ea8): FCL vanilla inproc waits only on the present credit (1.00/frame). BSL waits 7 times per frame on three kWaitApplied rows plus 22 follow-on quiesces; see WAIT-AUDIT.md. User decision applied in 2fbcc224: fire-and-forget rows async, inproc creates and PBO readbacks no longer wait, and the dual block (MOBILEGL_IPC_ROLE_SPLIT_STATE, now default on) lets a barriered verb cost one wait. BSL census after it still owed (gpuhunt only; FCL's 1.21.4-Fabric profile exited with signal 34 at JVM start on both backends in the last attempt).
  • db915f76: a client parked on the present credit is rung only by the credit (apply-thread futex wakes 0.056 ms/frame before).
  • Frames in flight (0b96a3ef): MOBILEGL_FRAMES_IN_FLIGHT (default 3) drives Magma's frame contexts, Espryt's post-present fence wait and the split present credit max(1, N-2); the Magma name is an alias. Default latency unchanged; the FIF A/B is the user's input for the default.
  • Present credit 2 (cens, cpuhunt, all VALID): Magma 309.0 -> 319.9, Espryt 299.1 -> 319.1 fps vs MobileGlues 321.9 in the same session; apply CPU 1.40-1.43 vs MobileGlues' GL thread 1.57. Credit 2 costs a frame of latency: user decision. The remaining inproc gap is the queueBuffer fence wait (GPU-side), not CPU.
  • BSL at cpuhunt (GPU 903 MHz) reaches GPU 95 C and kgsl thermal_pwrlevel 1 (834 MHz cap): the census run was INVALID twice and the job was stopped. Run BSL only at gpuhunt.
  • Apply-thread frame (Magma inproc): on-CPU 1.75 (0.2 of it spin), queueBuffer fence wait 1.45, parked 0.24 ms.
  • Magma apply on-CPU by verb: draws 0.55 (SetupWireDraw 0.40, of it descriptor binding 0.13), present 0.37 (End CB 0.10, queueBuffer CPU 0.08, submit 0.07, wire-store sweep 0.035), clear 0.19 (the frame's recording begin 0.09 + pass begin 0.05), buffer writes 0.09, blit 0.06 (two image views and a VkFramebuffer created and retired per blit).

• Device contention, root cause (2026-10-08): the anland app was relaunched by fclab.sh's own end-of-run monkey (launchedFromUid=0); its activity takes the foreground back whenever paused, so FCL launched over it never reaches the world (RenderDoc job: 0 of 4 worlds). c41dfdda: bench_session.sh start force-stops it and stop relaunches it only if it ran before.

• Open user decision: Espryt's apply thread spends 0.06 ms/frame in LatchIfGuiltyBeforeApply (glGetGraphicsResetStatus is a kgsl ioctl, queried on every wake). Rate-limiting it to 2 ms breaks ServerLoopEglLatchTest.AGuiltyResetEndsTheSessionBeforeItsNextRecord..., the designed promptness guarantee, so it was reverted. Trading that guarantee for 0.06 ms is the user's call.

• CI: 4a8ecf9a green. 49c6394d: one job failed on a hosted runner's apt-get update timeout (45 min, infrastructure); the failed job is re-run.

• Next:

  • RenderDoc (rdc GLES layer, remote server stopped): Espryt vs MobileGlues BSL pass structure;
  • S1 (client validate 0.25 ms) and S3 (backend by-handle syncs, descriptor resolve) for the CPU floor and the inproc apply thread.

Status (2026-10-08)

Branch: p15impl (worktree .claude/worktrees/p15, short path W:/p15), pushed to feat/disaggregated.

S0.1 parity audit: written.

S0.2, Magma wire non-draw ports:

• M1a, clears become part of the draw pass (ClearWireFramebufferInPass; PrepareWireDrawPass split out of SetupWireDraw):
  • A whole-area clear that begins the pass begins it with a LOAD_OP_CLEAR variant of the pass's render pass (RenderPassEntry::clearVariants, compatible with the framebuffer).
  • Any other clear (into the open pass, or scissored) is vkCmdClearAttachments in the pass. A forced pass restart for depth clears (an LRZ hypothesis) was tried and reverted: it cost CPU and fixed nothing.
  • Kill switches: MOBILEGL_MAGMA_INPASS_CLEAR=0; MOBILEGL_MAGMA_INPASS_CLEAR_DEFAULT=1 puts default-framebuffer clears in the pass too (off by default, see the open item).
• Open item: default-framebuffer clears stay standalone. With them in the pass, the openra retrace on Adreno 750 loses its palette-sampled sprites (SSIM 0.956378, deterministic). What was measured:
  • Both vkCmdClearAttachments and LOAD_OP_CLEAR fail; so does splitting the clear calls.
  • Colour-only or depth-only in the pass, with the other part standalone, passes.
  • Event traces: the first draw flushes the recording (the palette glTexImage2D's upload flush, FlushPendingCommands) right after the clear. Command order otherwise matches the standalone path.
  • Not explained yet. Lavapipe and the InPassClear scenarios on FBOs are clean.
  • Ruled out by reading: a missing ordering edge. Default-framebuffer images get the same pass-begin barrier as FBO images (a full ALL_COMMANDS memory barrier, or their transition), with their layout tracked per swapchain index through the swapchain object.
  • Still open: the in-pass path commits the freshly acquired swapchain image (DefaultFramebufferWriteIndex(true) in PrepareWireDrawPass) at the clear; check whether the standalone path's clear and the in-pass clear address the same index on the trace route.
  • Cost of leaving it: small for FCL (MC renders into its own FBO and blits to the default one).
• M2, draw-pass cache across frames: one cache, entries pruned when their image epochs move, destroyed after their last submit. Kill switch: MOBILEGL_MAGMA_PASS_CACHE=0.
• M3, blit descriptor sets: one pool per frame slot.
• M9, converted vertex streams (wrongly marked "have" in the first audit). The wire arm re-converted the whole remaining stream on every draw: Sodium's multi-draws over one arena cost 49 ms/frame of CPU on BSL (19.5 fps against dev's 64.7).
  • Now one conversion per (store content serial, layout), kept across frames in VkBufferManager (LookupConvertedStream / StoreConvertedStream).
  • Each entry owns a vertex buffer. Bounded at 192 MB (least recently used first); entries idle for 256 frames go. A replaced buffer is released when its frame slot comes round.
  • The content serial is process-wide monotonic and moves on every host write, respecify, GPU-write mark, shader-writable bind and donation.
  • Kill switch: MOBILEGL_MAGMA_VERTEX_CONVERSION_CACHE=0.
• M4, write renaming. A busy glBufferSubData used to take a staged copy, which ended the render pass with two full barriers (FCL: ~5.6 per frame, all on one 288-byte store). Now:
  • A store of 64 KB or less keeps a host shadow (64 MB budget), from respecify on.
  • A busy write into a shadowed store gives it a fresh VkBuffer filled from the shadow and releases the old one like a glBufferData orphan. No copy is recorded and the pass stays open.
  • GPU-written marks, shader-writable binds, donation and import drop the shadow.
  • ReadWireBuffer serves shadowed stores from the shadow, so no host wait.
  • Kill switch: MOBILEGL_MAGMA_WRITE_RENAME=0.
• Tests:
  • InPassClearScenario: 4 cases, monolith and split, both backends.
  • ConvertedVertexStreamScenario: 3 cases (reuse, same-frame sub-data, cross-frame sub-data). Red-once: a lookup that ignores the content serial turns both sub-data cases red.
  • WriteRenameScenario: 4 cases (order and carry, one-byte writes, uniform and index buffers, multi-frame). Red-once: a rename that skips the shadow fill turns all 4 red, which also proves the rename engages.
  • Red-once checks: the colour index and the scissor (2 cases red); the depth clear-load bit (depth/stencil case red).
  • Syncval gates green (cache 7/7, run-ahead 14/14), plus the InPassClear cases under syncval.
• Gates:
  • SSIM 24/24 (openra, rd12, bsl × 4 arms × 2 backends) on p15e.
  • Host unit and integration-gpu green, apart from the known environmental ServerSpawn / FuzzArm2 / PeerLatch / spawn ColdStart failures.
  • CompositorRecovery flakes under -j16 and passes alone 3/3.

S0 milestone (one device session, FCL, interval 0, 2 reps; runs/ms-s0i):

scene	build	Magma CPU ms/frame	Magma fps	Espryt CPU ms/frame	Espryt fps	GPU busy
vanilla 1.21.5 (CPU)	fin	3.27	170	2.81	190	12-15 %
	p15h (S0 without M4)	2.59	191	-	-	15 %
	p15i (S0)	2.56	190	2.77	193	13-15 %
	dev	1.79 (n=1)	234	2.14	218	14 %
	MobileGlues	1.59	256			15 %
BSL (GPU)	p15i	7.26	77.2	7.61	70.6	99 %
	dev	13.85	66.1	7.17	70.5	85-100 %
	MobileGlues	6.25	78.2			98-100 %

(BSL before the converted-stream cache: Magma 19.5 fps at 26 % GPU busy, 49 ms CPU/frame.)

• Espryt's base lib (p15plan, unchanged) read 2.84 in the same session: the earlier "p15e Espryt regression" was session variance. S0 does not touch Espryt.
• Target status. Magma BSL is met (within 1.3 % of MobileGlues, GPU-bound). Espryt BSL is GPU-bound at 99 % and 10 % below MobileGlues, same as dev: a GPU-side gap still to explain (the load/store and clear audit of PLAN §0.1). CPU scene: Magma 2.56 vs MobileGlues 1.59, Espryt 2.77.
• Where Magma's CPU goes now (p15i profile, runs/prof-hi, ms/frame inclusive): VerbChannel::Port 0.85, OnDrawVbo 0.62, SetupWireDraw 0.46, Present 0.32, MGPipeValidateForVerb 0.27, in-pass clears 0.18. The draw path is S1-S3's; S0's non-draw ports are done. Proof that M4 engages: StagedWireRangeCopy 0.067 is gone and RenameBusyWireStore costs 0.048 (a VMA allocation per rename; a recycle pool could take most of it).

Stage P: dropped for the target.

Harness

purpose	where
FCL probes and reducers	tools/device_bench/disagg/ (README "P15 FCL probes")
FCL vanilla A/B, H2 (pinned, SF frame source, stability warmup, sp=1 profiles after the windows)	scratchpad p15/fclab2.sh "<name>:<lib>:<backend>[:sp[:transport[:K=V,...]]] ..." <reps> -> fcl_bench.sh; fclsum.py, residency.py, diffprof.py, prof_prep.sh
FCL milestone (CPU + BSL scenes, fin / new / dev / MobileGlues)	scratchpad p15/fcl_milestone.sh, fcl_scene.sh, fclab.sh, fclsum.py
SSIM gate (openra, rd12, bsl × 4 arms × 2 backends)	scratchpad p15/ssim_gate.sh; matrix_p14.sh now takes PREP_WLS and a bsl workload
host CI-shaped build (WSL archlinux)	~/mgl-p15-ci31, scratchpad p15/wsl_ci.sh, w_suite.sh, w_syncval.sh, w_sv_one.sh, w_one.sh
trace APK builds	scratchpad build_trace.sh W:/p15 .<tag> (rerun once on the IncrementalSplitterRunnable failure)

Host-build trap: editing a header while ninja is compiling leaves objects newer than the header but built from its old text. This happened once and gave a bad_alloc in every scenario. Never edit sources during a build; touch the edited headers if in doubt.

Device facts:

• Clocks: CPU 2035.2 MHz on policies 2/5/7 and 1574.4 MHz on policy0, GPU 680 MHz (new default since 2026-10-08, pending the soak). Pinned per session by bench_session.sh, which every devjob.sh job runs.
• Frequency daemons are stopped only inside a bench session: thermal-engine, perf2-hal-1-0, vendor.perfservice, performance and hyperschedule_hal_service. Their prior state is in /data/local/tmp/p15-bench-session while a session is open, and they are restarted and verified on exit. If that file exists with no job running, a session was left open: run bench_session.sh stop.
• The perf stack's game-mode caps in /sys/kernel/msm_performance/parameters/cpu_max_freq survive its services and silently override the pin. The session releases them.
• FCL's original lib md5 is 00c09f0a….
• MC 1.21.5 options md5 is 93b3f708…; it is backed up at /data/local/tmp/p15-options.txt.
• Iris properties are backed up at /data/local/tmp/p15-iris.properties.
• fcl_scene.sh restore restores Iris; fcl_p14.sh restore restores the lib and config.json.
• The anland desktop is stopped during runs and restarted afterwards.