WIP: perf(vk): search storage buffer tables in loops in every global memory fallback on MoltenVK and KosmicKrisp #696
No reviewers
Labels
No labels
area/accessibility
area/audio
area/input
area/install
area/menu
area/renderer
area/saves
area/upscaling
beanstalk: approved @ 1697603
beanstalk: approved @ 2c5a62e
beanstalk: approved @ 4fd82b7
beanstalk: approved @ 64d6d09
beanstalk: approved @ 6f91fae
beanstalk: approved @ 70a78f9
beanstalk: approved @ 8d361dc
beanstalk: approved @ 9d8356e
beanstalk: approved @ abf2227
beanstalk: approved @ d82f202
beanstalk: approved @ e5f1e40
beanstalk: approved @ ee8ab5f
ci: approved
good first issue
gpu/amd
gpu/igpu
gpu/intel
gpu/nvidia
help wanted
kind
bug
kind
chore
kind
docs
kind
feature
kind
performance
kind
question
needs measurements
platform/linux
platform/macos
platform/steam-deck
platform/windows
preview
priority
critical
priority
high
priority
low
regression
status
blocked
status
confirmed
status
duplicate
status
invalid
status
needs-info
status
wontfix
testing wanted
ci: approved
No milestone
No project
No assignees
1 participant
Notifications
Due date
No due date set.
Dependencies
No dependencies set
Reference
MagicBeanDev/Longshot!696
Loading…
Reference in a new issue
No description provided.
Delete branch "mooki/Longshot:mac/gm-loop"
Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?
Type: perf · Risk: low · Tested on: macOS 26.7.1, Apple M4 Max (MoltenVK 1.4.2), game-free at this head; GPU probe GL-01 on arm64 (history) · Needs: Windows, Linux, macOS game run
Why
On a Mac, the start-up precompile spends minutes on a few giant compute programs, and some fail in Metal's compiler service
(Mac start 18: modules of 246,000-262,000 SPIR-V words, 517,000-561,000 with every call written out). Each global memory access the
storage buffer pass could not bind calls a fallback that searches every storage buffer of the program, and a storage buffer table
is searched entry by entry, written out (about 148 SPIR-V words an entry). SPIRV-Cross, MoltenVK's translator to Metal, makes
every function
always_inline, and KosmicKrisp's NIR inlines too, so Metal compiles every table entry's test again at everyglobal access. Intel's Mesa driver had the same problem and searches the tables in a loop (
global_table_loop); this PR does thaton MoltenVK and KosmicKrisp, in every fallback. It is part of the macOS port. See #420.
What changed
On Apple only, for MoltenVK and KosmicKrisp with
shaderStorageBufferArrayDynamicIndexing,Profile::search_tables_in_loopsmakes every global memory fallback search each storage buffer table in one loop over its entries (the table indexed by the
loop's counter), the 8/16-bit stores' and float adds' too, which Intel's form leaves written out.
RX_VK_GM_LOOP=0turns it off.The program cache's stamp gets a word only when it is on; every other driver's SPIR-V is byte for byte as before.
gpu/vk/eden/shader_recompiler/profile.h:Profile::search_tables_in_loops;backend/spirv/spirv_emit_context.cppdefine_body: the loop's counter is made when Intel's loop or this flag asks and the program has tables, right after a CAScaller's own variables (every
OpVariablestill leads the function's first block);mma_layout.h: its comment.gpu/vk/vk_shader.cpp: inside#if defined(__APPLE__),table_loops_wanted(driver, dynamic_indexing, env)andtable_loops_on()(once; logsvk: storage buffer tables searched in loops by every global memory fallback (RX_VK_GM_LOOP=0: written out));make_profilesets the flag in its Apple block;translator_stampadds"gmlp"only when it is on, after#694's
"sgv1".docs/development.md, theRX_VK_GM_LOOProw (on by default on MoltenVK and KosmicKrisp too).tests/test_gm_loop.py(new) withtests/gm_loop_ir.cpp(new):seg_shader_ir.cpp's table programs and big syntheticones (
big: 46 global accesses of 10 kinds, a 70-entry table and 16 single buffers, the culling programs' shape;big-seg;big-two: tables of 24 and 12) in 6 profiles and 4 forms (written out, Intel's, this flag, both): spirv-val, loop counts,written-out words (#695's
spirv_profile::count), every CPU run equal across the forms, the flag alone changing noneof the 22 programs without a table, and with
--basethe off forms byte for byte against an older tree;--gpuwritesGL-01's inputs (the loop forms first).
tests/spirv_run.h:OpAtomicFAddEXT(this Mac's float adds).tests/test_amd_subgroup_profiles.py,tests/test_subgroup_vertex.py: atable_loops_onstand-in wheremake_profileis compiled cut out.
Measurements
Verdict: faster on the GPU (history: GL-01 on arm64, pipeline creation of the big program 15.36 s written out → 1.45 s in
loops, and 2.97 s → 0.37 s for the two-table one, every byte of every buffer the CPU's); game-free at this head the big
program's SPIR-V falls to 0.20 of its words and its written-out words to 0.19, its Metal source to 0.32, with the same words on
the CPU in every form. Cost: the CPU interpreter runs 1.48 times the instructions where the search runs (big: 3.74M → 5.54M,
all lanes); the GPU's run time is not measured.
Hardware: macOS 26.7.1, Apple M4 Max, 64 GB, Apple clang 21 (game-free at this head; GPU results are the probe's history)
Scene: none (synthetic table programs in the back end's shapes, emitted, validated, run on the CPU interpreter and converted by
SPIRV-Cross)
Method:
tests/test_gm_loop.pyat this head with--baseagit archiveof this PR's base and the Vulkan SDK'sspirv-cross(1.4.363.1), arm64 and
--arch x86_64(Rosetta); with this PR's test files on the base, which must fail. On the GPU: probeGL-01 (GmLoop's report), one admission on arm64, at the topic's commit
f55ed669. Exact checks: one run per route.How to reproduce:
python -I -B tests/test_gm_loop.py --headers <SPIRV-Headers/include> --spirv-val spirv-val [--spirv-cross <spirv-cross>] [--arch x86_64] [--base <git archive of the base>]Baseline: the "before" column is this PR's base (#694 with #695 merged,
fda98ed6), whose stamp words andspirv_profile.hthis PR uses (main has neither); its modules are the test's written-out form (84 of 84 byte-identical).fda98ed6be4a1387big, this Mac's profile: SPIR-V words / written outbig-two: SPIR-V words / written outbig: Metal source (SPIRV-Cross 1.4.363.1), bytes / lines--base)BASE modules=84 same=84)test_gm_loop(this PR's test)vk_shader.cpp:table_loops_wantednot found; no loop-formMEASURElines)gl-big-written15.36 s,gl-big-two-written2.97 sgl-big-loop1.45 s,gl-big-two-loop0.37 s; all four MATCH (88/0, 42/0 buffers)Flags and settings
One switch's default changes on Apple; no new switch. The diff against main also shows the switches of the PRs it stacks on,
theirs to list:
RX_VK_SPV_PROFILE,RX_VK_SPV_PROFILE_MIN(#695),HOS_KEEP_FREED_PAGES,HOS_ZERO_ALL_PAGES,RX_NVN_WATCH_AFTER,RX_NVN_WATCH_ALL,RX_NVN_WATCH_TEXELS_SRC(#480),RX_VK_LIBRARY(#438),RX_VK_DLSS_ACTORS,RX_VK_GPU_DUMP,RX_VK_MESH_IND_COUNT_WORD,RX_VK_NO_UPSCALE_STUB(#658),RX_VK_TEXEL_CODECS(#649),RX_VK_SET_FOR_TABLES(#643) andRX_VK_SET_FOR_LENGTHS(#644).RX_VK_GM_LOOP=0or10writes them out there as beforeTesting
Tested: on macOS 26.7.1, Apple M4 Max, at
be4a1387, this PR's head before the rebase ontoe090cc48(main6c9edffe,#694's and #695's stacks, this PR), game-free, every run under the shared check slot with a fresh HOME and TMPDIR:
tests/test_gm_loop.py --basethe base, withspirv-cross, arm64, and--arch x86_64: exit 0, as in Measurements. On thebase with this PR's test files: fails (122 failures).
tests/test_gm_loop.py --gpuat this head writes GL-01's 525 inputs (the four modules, every buffer's input and expectedwords, the manifest) byte for byte, so GL-01's result holds for this head's modules.
tests/test_seg_shader.py --base-treethe base, arm64 and x86_64: exit 0, 139 of 139 identical.tests/test_subgroup_vertex.py --base-treethe base, arm64 and x86_64;test_msl_depth,test_amd_subgroup_profiles,test_program_stamp_knobs(19 switches),test_program_cache_format: exit 0.spirv_emit_context.cppandvk_shader.cppcompiled whole with main 6c9edffe's renderer flags for arm64 and x86_64:4 of 4, exit 0 (scratch tree with #476, #492 and #490).
objects, 1,216 name/arch checks, closure 565 symbols a route, 0 undefined.
[mvk-error]); the topic's full suite with only its base's own failure. Every changed line here is the topic's, line for line.reports/PubWave-files/PubShader3/(proof/gml-be4a1387-*.log,keep/gml-be4a1387-gpu,compile/gml-gm-loop-be4a1387/,equal-lines.txt,stamps.txt,offapple-gml-fda98ed6-be4a1387.txt,merge-tree.txt,wave/).e090cc48, at90764f77(wasbe4a1387): Sweep2's checks of this head (the C/C++ itchanges compiled, and its own tests run, on arm64 and x86_64 where they apply) gave the same results as at
be4a1387;python -I -B tests/run_all.pyon wave Sh3's merge57c9c4ab, which carries this head: 578/31/18(passed/failed/skipped) against main e090cc48's 544/32/17 on this Mac, no new failure
(
reports/2026-11-14-rebase-sweep-2.md).Not tested: the game at this head, and no GPU run at this head (GL-01 is history, on modules byte-identical to this head's);
GL-01 did not run on x86_64 (the compile runs in Metal's compiler service whatever the probe's architecture) nor on KosmicKrisp.
Windows and Linux: not built there (3 changed files differ from the base's off Apple; the counter's condition reads the flag,
off there); its test request covers it.
Must be tested:
once (
gmlpin the stamp), thevk: storage buffer tables searched in loops …line, and the precompile's slowest computeprograms taking less time than at the base (by hand: the owner, the log's
vk:and[mvk-error]lines)90764f77, it carries #694 and #695 with the PRs theystack on) and main
e090cc48the same way and start each to the title, and runpython -I -B tests/run_all.pyon Linux,expecting the build to compile this PR's changed files, the shaders prepared once more (a new translator stamp), and every
other line to match main's (by hand: test request T-XXXX)
Risks
What could break: on MoltenVK and KosmicKrisp, every global memory fallback with a table becomes a loop: a fault would change
a value the fallback loads or stores (every table program's CPU runs give the same words in all four forms), or cost run time
where a search runs (1.48 times the instructions on the CPU; the search is the miss path of accesses the storage buffer pass
could not bind). Other drivers: nothing changes; only the stamp.
Turning it off:
RX_VK_GM_LOOP=0(the entries written out, as before; in the program cache's stamp).Compatibility: every platform's shaders are prepared again once (the back end is in the translator's stamp:
6f05a8d7bf670184→5ad12149fc77e534); on MoltenVK and KosmicKrisp the translator stamp also gains"gmlp".kProgramCacheFormatstays 3. Nothing changes in saves,longshot_options.inior the vk ABI (MKWVK_API_VERSION).Reviewer notes
fda98ed6..be4a1387, three commits,-xfrommacos/gm-loop(94ea1c19,f55ed669,81254a30). One conflict, indocs/development.md's switch table (main's newer rows kept, only theRX_VK_GM_LOOProw is this change's). Their changedlines are the topic's line for line in all 10 files (
macos/integratedd3a00c2e). Readdefine_body's counter, thentable_loops_wanted, thentest_gm_loop.py's forms.3b7e95a8: thetable_loops_onstand-in goes into its fixture) and#695 (merged in
fda98ed6, clean:gm_loop_ir.cppcounts written-out words with itsspirv_profile.h). Until theymerge this PR's diff shows their commits too. #697 stacks on this head.
profile.h,vk_shader.cpp,test_amd_subgroup_profiles.py): keep both, stamporder
"msl2","mslb","sgv1","gmlp","lzlp"(asmacos/integrated). #698 (vk_shader.cpp's Apple block inmake_profile,test_amd_subgroup_profiles.py; and itstest_vendor_fixes.pyfixture needstable_loops_on): keep both;whichever lands second adds the cut-out fixtures' stand-ins (the macOS integration's
02b10861; the wave's merge carries them asits one fixture commit). #681 and #652 (and #666, #667):
docs/development.mdswitch rows, keep both.git merge-treewith#692, #677-#680, #686: clean. The other conflicts with #650/#652 are the base's, as in #676's notes.
spirv_emit_context.cppandvk_shader.cppare compiled everywhere and the stamp changes, so every platformprepares its shaders once; the loops are on only on MoltenVK and KosmicKrisp. Not split for that reason.
reports/2026-11-14-*.md(the port's design notes), which are not in this repository.Issues
See #420
Checklist
Everyone
type(scope): description) of the status line's type.main(maine090cc48; head90764f77, wasbe4a1387: this PR's own commits replayed one for one, old → new:fda98ed6→af943f10,b81dbdc0→5fdc85b3,76207b2c→8ae64400,be4a1387→90764f77; the commit names elsewhere in this description are from before the rebase).python -I -B tests/run_all.pypasses (any failure that also fails onmainis named). (On the wave's merge77333ce0: #693 on #692, #697 with this PR, #694 and #695, #698 with #654, and one fixture commit for the cut-outmake_profilestubs: 565 passed, 31 failed, 18 skipped against main 6c9edffe's 531/32/17 on this Mac; the 31 failures are main's own and nothing that passes on main fails;test_collect_widenow passes; 33 new tests pass,test_gm_loopamong them;test_darwin_audio_service, Darwin-only, is skipped by the runner;reports/PubWave-files/PubShader3/wave/full-77333ce0/. After the rebase onto maine090cc48(head90764f77): wave Sh3's merge57c9c4ab, 578/31/18 against main e090cc48's 544/32/17, no new failure.)third_party/untouched (a new folder with aPROVENANCE.mdinstead).When it applies
Assisted-by:/Co-Authored-By:trailers.mainand passing here. (test_gm_loopfails on this PR's base with thisPR's test files; on
maintoo, which has neither the flag nor the fixture.)tests/that reads changed source updated in this PR, not weakened.Every scan down vk_memory.cpp's import table by start (pool_lookup's covering import and merge plan, bg_drain, prefetch_chunks, import_in_background, memory_note_gpu_write and memory_guest_imported) stopped once an import ended more than 1 GiB below its address, on the belief that no import is larger than that. pool_lookup's own merge escape leaves an import above 1 GiB over the smaller ones inside it ("left overlapping"), and the device allows imports up to max_import_size: a scan stopped at a small import inside a large one, missed the large one, and the same bytes were imported again, two memories over the same bytes. import_reach.h counts the live imports by span class; its bound is above every live span, within twice the largest. imported_add and imported_take, now the table's only ways in and out, keep the count. A scan stops only where no import further down can reach its address, so it also stops sooner than before when the imports are small. The covering-import checks in pool_lookup and import_in_background look past the last import at or below the range for the same reason. Tests: test_import_reach.py runs the actual scans with a 4 GiB import over a 16 MiB chunk, left by the merge escape (imports are recorded ranges: no payload, no Vulkan, no game). Its lookup, query, note, drain, background and prefetch cases fail on main5e072fc8and pass here, and a source check keeps every change to the table in the two helpers. test_import_windows runs pool_lookup with the helpers; test_mirror_gpu_only names the new publication point. Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]>044635ea added vma_startup_rollback (vk_vma.cpp, run after a failed replay_start), which calls vmaDestroyAllocator. vk_vma.cpp includes vk_work.h last so that RX_VK_RECORDER=defer/thread drains before its destructions, and every such boundary call in a vk_work.h file must be in RX_REC_BOUNDARIES with a drain-first macro. This one was not, and test_recorder_sync caught it ("vk_vma.cpp calls ['vmaDestroyAllocator'], which vk_work.h does not drain before"): it passes at 58c5c5aa (044635ea's parent) and fails at 044635ea. Add it to the list and to vk_work.h, next to vmaDestroyBuffer and vmaDestroyImage. With the recorder off (the default) boundary() is a relaxed load and a branch. Rollback runs before any image or buffer exists, so nothing should be held there today, but the allocator is no longer destroyed while a recorder could still hold packets. The test is unchanged (sources: 42 boundaries drained, was 41). Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]>A guest span larger than one device allocation (the cap on MoltenVK/M4 Max is 41,747,087,360 bytes) is bound as pieces: one descriptor per allocation segment, at the descriptor's own binding (reports/2026-11-14-full-range-design.md sections 4.1-4.4). This is the shader half; the draw side (descriptors, layout, gathers) comes later. - runtime_info.h: SegEntry {Storage|Table|TexBuf|ImgBuf, desc, pieces} and RuntimeInfo::segmented. - Back end: a segmented storage buffer is an array of pieces at its binding (a table count * pieces, entry k's piece j at k * pieces + j); its loads, stores and atomics call DontInline helpers made after main, which find the piece by the pieces' OpArrayLength in order, with constant indices. The global memory fallbacks sum the pieces' lengths for a segmented descriptor's bound end and branch to its piece (single, native candidate, table written out and in the loop). Texel and image buffers are arrays too, their fetches, reads, writes and atomics through helpers that pick the piece by OpImageQuerySize, and a texel buffer's size query sums the pieces. ImageQuery was declared for every module already. With RuntimeInfo::segmented empty nothing new is made: the SPIR-V is byte-identical. - vk_shader: SegSig (entries, hash) on Program, seg_sig and seg_variant; program_segmented finds or translates the variant of a plain program with plain's texture questions and answers and checks its descriptors are plain's; program_pick, mesh_program_locked, program_find_plain, loaded_variants and portable_variant keep the plain and segmented variants apart; every stage's RuntimeInfo::segmented comes from Program::seg. - vk_progcache: a segmented variant is never written to the program cache nor listed among the loaded programs. - tests/test_seg_shader.py + tests/seg_shader_ir.cpp: synthetic IR programs through the real back end, plain and segmented; structure checks, spirv-val (Vulkan 1.3, uniform buffer standard layout), and with --base-tree a byte comparison of the plain modules against an older tree. Five source-reading checks follow the new Program field and the atomics' new branch. The translator stamp changes with this (eden/, vk_shader.cpp, sizeof(Program)): every program cache is rebuilt once. Land it in the same release as the vk_api.h change that already does so. Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit b7928876dab846485f667c1c934d34d25ecef035)The interfaces the four segmented-consumer lanes (SegBind, SegXfer, TexelDesc, NullShader; reports/2026-11-14-seg-consumer-plan.md section 3) code against, frozen before they fork. Inert: no caller of anything new, no SPIR-V, layout, push range or stream change, sizeof(Program) unchanged. - vk_internal.h / vk_memory.cpp, SegMem's consumer interface: gpu_span_any() (a relaxed count of the live domains, stored in seg_commit; domains are kept for the run), gpu_span (gpu_buffer's flavour of gpu_span_bind: import buffers, no written marks, no mirror), SpanLayout::bind_stamp (gpu_bind_stamp(): a segment can be imported again with its cuts kept, so cut_gen alone never keys piece buffers), span_unused_piece's semantics ({null_storage, 0, 1}), and the SegArena API (SegArenaRef, seg_arena_take, seg_gather, seg_scatter; stub bodies after stream_alloc that give no room and log, SegBind's to fill). - Review fixes in the same interface (renderer-core review P2-3, P3.2): every piece of gpu_span_bind carries its buffer's device address (the import's or the mirror's; 0 only with bufferDeviceAddress off), and its one-piece path stores the translated guest address, not a virtual one. - vk_texture.h/.cpp: texel_view_pieces / texel_piece_views, stubs that return 1 and false (TexelDesc's to fill). - vk_shader.h: Program::presence_words, in what was padding. - Back end: PRESENCE_PUSH_OFFSET (88), Profile::emulate_null_descriptors, Bindings::presence / presence_read with the bit numbering rule. - tests: test_resolver_coverage lists gpu_span_bind / gpu_span sites too (scoped to gpu/vk: gpu/render has an rx::gpu_span of its own), checks that gpu_span follows its own gpu_buffer, and splits SITES into SITES_BASE plus one block per lane. test_segmented_domains executes the contract (the count 0, 1, 2 -> 1 on a merge, 0; gpu_span's pieces; addresses with the fixture's gpu_buffer_bind returning none as the real one does; the bind stamp; a virtual address's guest). test_seg_shader accepts a base tree of this back end's generation and compares every module. - docs/segmented-binding.md: the gate (every new behaviour Apple-only, other platforms byte-identical) and one heading per lane. Conflict on this branch (not with main): tests/test_seg_shader.py's docstring, against the array_pointer_calls paragraph #P20's msl-arrayptr port added; both kept, this paragraph first. Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit 95fa06d4e6526601bd2e1bc88c2f8f5720855350)The segmented single storage array's case (plan 4.3 item 5) had no negative: the check always cut its own tree. With --source <B2 archive> it fails as required ("moltenvk.segmented_single want=set got=push"). Conflict with #P28 (read_write textures; not with main): the docstring keeps #P28's paragraph with this usage line, and main() cuts from --source's vk_draw.cpp with #P28's read_write count (as in the macOS integration, Integration 17). Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit 5824f6828e21cf810dcceaa6be425a9224b15994)plaine37c097da2plaina997b3629aDefineImages and DefineImageBuffers declare one image whatever the descriptor's count, while Image() indexes the variable when the count is above 1, so such a module fails spirv-val ("OpAccessChain reached non-composite type"); B2 has it already, on every platform. The null_img* and null_imgbuf* helpers take their element the same way and share it. Found while extending the fixture; declaring the arrays changes every platform's SPIR-V and is left to the owner. Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit 83e7e18b4fee477f1e6901871ad37efe8f23d5bf)SPIRV-Cross (MoltenVK 1.4.2's pin 6c09849f) prints an OpImageRead's result, and a pure read helper's call, where the value is first used, and nothing orders it against the same invocation's later writes and atomics on that image: in MSL the read ran after them and returned the later value. TexOrder's TO-01 probe proved it on the GPU for LS's plain output, with and without the NullShader bit, on both CPU routes (reports/2026-11-14-tex-order.md). - Profile::materialize_image_reads, set by make_profile on Apple for MoltenVK only, with its translator stamp word ("rord") only when on. - emit_spirv_image.cpp InPlace: with the flag, every storage image and image buffer read's result (the plain read, the segmented read helper's call, a carrier codec's element reads) is stored to a Private variable at the read and loaded back; SPIRV-Cross prints a store where it stands. Private, since a Function variable must lead its function's first block; in the entry point's interface from SPIR-V 1.4. Off: no new ID, every module byte for byte as before. - tests/seg_shader_ir.cpp: order-* modules with the flag; the read-in-place rule (every read and read helper call stored at once), their flag-off twins breaking it, CPU runs equal to the modules without the flag, and the flag alone changing nothing without image reads. test_seg_shader.py: order- modules required; a base tree without the flag builds them with TEX_ORDER_BASE and they are not compared; --source against it fails. - tests/spirv_run.h runs Private variables (fresh per invocation) and OpMemoryBarrier (a no-op one invocation at a time). - docs/segmented-binding.md: a TexOrder section. Conflicts on mac/null-shader (#P33), with MslArrayPtr's tests that #P33's last commit carries, not with main; resolved as macos/integrated did (Integration 22, b08694d8): tests/seg_shader_ir.cpp keeps both sections and both calls (msl_arrayptr, then tex_read_order); tests/spirv_run.h keeps both storage classes (Uniform, then Private); tests/test_seg_shader.py keeps both docstring paragraphs and presence checks, leaves 'msl-' and 'order-' out of an older generation's set, and compares with a base in one loop (an order- module skipped for a base without the flag, identical counts as the same, a different segmented one listed under --changed-segmented, anything else fails). Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit a9aad5bcd6f4cce3d9fcff8b231da9628e7da4b3)Metal has SIMD-group functions and lane ids in kernel and fragment functions only (MSL 4.1 section 6.10), MoltenVK 1.4.2 lists fragment, compute and tessellation control in subgroupSupportedStages, and SPIRV-Cross 6c09849f refuses SubgroupLocalInvocationId in a vertex function ("Subgroup builtins are not available in this type of function."). Run #16 lost graphics pipelines to it in the precompile. On MoltenVK only, make_profile clears Profile::supported_subgroup_stages for the stages Metal runs as vertex functions (VertexA, VertexB, tessellation evaluation, geometry) that the device does not list, and the translator stamp gets a word for it then. The back end's path for such stages is each invocation as lane 0 of a 32-lane warp whose other lanes are not active: the lane masks of lane 0 (SR_GTMASK 0xfffffffe and SR_GEMASK 0xffffffff, not 0 and 1), SHFL.UP/DOWN/BFLY's bounds from lane 0 (not always out of bounds), and no subgroup barrier. Every other driver keeps every stage: its SPIR-V is byte for byte as before. tests/test_subgroup_vertex.py builds make_profile against stub devices and the back end with tests/subgroup_vertex_ir.cpp: 19 warp operations in vertex programs and 5 in tessellation evaluation ones, each emitted native and for MoltenVK, run on the CPU (tests/spirv_run.h now runs vertex inputs, outputs and a subgroup of one active lane) against the guest's lane 0 alone (PTX ISA's shfl, vote and lane masks), every SHFL b, clamp and segmentation mask; no subgroup construct may be left in a MoltenVK module of a vertex-side stage. reports/2026-11-14-subgroup-vertex.md. Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit a878cef81d0f98c9517e79d51c29cbb7ae503ba6)SPIRV-Cross's MSL and Mesa's NIR inline every function, so each global access of the culling programs carried its fallback with every table entry written out: compute modules of 100k-560k SPIR-V words that Metal's compiler service compiled for minutes or failed in. Profile::search_tables_in_loops (set by make_profile on Apple only, for MoltenVK and KosmicKrisp with shaderStorageBufferArrayDynamicIndexing; RX_VK_GM_LOOP=0 off) loops each table in every fallback, the 8/16-bit stores' and float adds' too, which Intel's global_table_loop leaves written out. The program cache's stamp gets a "gmlp" word only when it is on; every other GPU's SPIR-V is unchanged. tests/test_gm_loop.py builds seg_shader_ir.cpp's table programs and big synthetic ones in the written-out, Intel, flag and both forms: spirv-val, loop counts, CPU runs equal, the flag alone changing no program without a table, and (--base) the off forms byte for byte against an older tree. spirv_run.h runs OpAtomicFAddEXT. Picked onto main 6c9edffe's line (mac/subgroup-vertex with mac/spv-size merged): one conflict, in docs/development.md's switch table, where main has rows this change's base had not (RX_VK_NO_INTEL_SERIAL, RX_VK_COMPUTE_QUICK_FIRST, the two HOS_VIDEO_ rows, main's RX_VK_DRIVER_FAULTS wording). Main's rows are kept and only the RX_VK_GM_LOOP row is this change's ("Intel's Mesa driver", as vk_coopmat.cpp's table_loop_wanted says on main too). Assisted-by: Claude Opus 5.5 Co-Authored-By: Claude Opus 5.5 <[email protected]> (cherry picked from commit 94ea1c19bb6c6f7e542d4bc86a798ef8b8bda10e)be4a13875590764f776c90764f776c231115f14cFolded into #848 (feat(vk): the SPIR-V back end on MoltenVK and guest spans past one device allocation)
Pull request closed