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Phase 8b: opportunistic QPU paths through public API

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Wires QPU dispatch for cycles 3 (VP9 MC), 5 (AV1 CDEF), 8 (H.264
deblock) through the public API. These three kernels have recipe
substrate = CPU, but per Issue 003 the mixed-kernel helper value
is real — the dispatch path must exist so override-mode callers
can request QPU on the side.

Pattern mirrors dispatch_idct8_qpu (lazy pipeline + per-call SSBO
alloc + memcpy + dispatch + readback). Each kernel has its own
push-constant struct (mc_pc 3-field, cdef_pc 3-field, deblock_pc
2-field shared with lpf).

Notable bug caught + fixed in test_api_opportunistic_qpu: the
initial dispatch_mc_8h_qpu sized src_max using CPU-side reach
(src_off + 3 + 8 + 7*stride), but the QPU shader reads src[
src_off + row*stride + 0..14] for row=0..7. Last block had 3
uninitialized bytes → 99.8% match → 100% after fix.

After this commit, the public API surface fully covers cycles 1-8:
  Cycle 1 (IDCT 8x8): CPU + QPU + AUTO bit-exact
  Cycle 2 (LPF wd=4): CPU + QPU + AUTO bit-exact
  Cycle 3 (MC 8h): CPU recipe; QPU override bit-exact
  Cycle 4 (LPF wd=8): CPU + QPU + AUTO bit-exact
  Cycle 5 (CDEF): CPU recipe; QPU override (untested in this
    test — bench_v3d_cdef is the authoritative 3-way M1)
  Cycle 6 (H.264 IDCT 4x4): CPU only (no QPU shader by recipe)
  Cycle 7 (H.264 IDCT 8x8): CPU only
  Cycle 8 (H.264 deblock luma-v): CPU recipe; QPU override bit-exact

Tests: test_api_opportunistic_qpu adds CPU-vs-QPU bit-exact
comparison for VP9 MC and H.264 deblock through the API.
test_api_idct, test_api_lpf, test_api_h264 still pass.

Per the locked Phase 8 architecture (project_phase8_architecture
memory): next session opens daedalus-v4l2 sibling repo with
Option B (kernel V4L2 shim + userspace daemon), Option γ (dlopen
FFmpeg parser).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Markus Fritsche
2026-05-18 14:50:41 +00:00
parent fd55f5ebc1
commit 0a99b16489
3 changed files with 396 additions and 9 deletions
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CMakeLists.txt
+4
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@@ -384,6 +384,10 @@ add_executable(test_api_h264
target_link_libraries(test_api_h264 PRIVATE daedalus_core)
target_compile_options(test_api_h264 PRIVATE -O2)
add_executable(test_api_opportunistic_qpu tests/test_api_opportunistic_qpu.c)
target_link_libraries(test_api_opportunistic_qpu PRIVATE daedalus_core)
target_compile_options(test_api_opportunistic_qpu PRIVATE -O2)
if (DAEDALUS_BUILD_VULKAN)
# (re-open the conditional so the closing endif() below balances)