36eca40ff2
Phase 4 plan + Phase 5 second-model review (PASS-WITH-REVISIONS:
2 YELLOW contract gaps applied) + Phase 6 v1 implementation +
Phase 7 verification including M4'' concurrent gate.
Phase 5'' review delivered cleanly — no RED bugs (cycle 1 lessons
applied successfully). 2 YELLOW findings baked into phase4 §4:
- stride >= 4 contract added alongside m.x >= 4 (finding 2)
- assert(...) in bench made a MUST not a suggestion (finding 4)
- V3D divergence-cost note: don't restructure to always-execute,
masked lanes consume clock anyway (finding 3, informational)
Phase 6 v1 first-light hit M1'' 100.0000% bit-exact on first run
(65536/65536 edges) — the cycle-1 v4 patterns (WG=256, 2-per-sg,
uint8_t SSBO, oob early-return discipline) baked in from start
worked as expected.
Performance:
M2'' = 19.645 Medge/s (50.9 ns/edge)
M3'' = 48.285 Medge/s (NEON baseline from phase3)
R'' = 0.41 (ORANGE band - doesn't auto-close per
cycle-1 calibration adjustment)
shaderdb: 160 inst, **4 threads**, 0 spills, 21 max-temps —
shader is already at the compiler ceiling. No v2/v3/v4 iteration
loop like cycle 1 because there's nothing more to extract from
the compiled shape. The 30x gap between theoretical instruction
throughput and measured wall-clock is divergence-tax + memory
latency, not compile quality.
M4'' concurrent matrix on hertz (8s windows):
NEON-1 LPF 41.131 Medge/s
NEON-4 LPF 33.726 Medge/s <- realistic CPU ceiling
(per-core 7-9; same
bandwidth-saturation as
cycle-1 F1)
QPU only 14.299 Medge/s
MIXED NEON-3 + QPU 36.049 Medge/s <- +6.9% over NEON-4
MIXED NEON-4 + QPU 31.892 Medge/s <- -5.4% oversubscribed
The "freed-core" pattern generalizes from IDCT to LPF: NEON-3+QPU
beats pure NEON-4 by ~7% in both cycles. Cycle-2 NEW finding:
**oversubscribed mode hurts for lighter kernels** (LPF -5.4% vs
cycle-1 IDCT +9.4%). Recommendation for higgs deployment hardens
to "always N-1 NEON cores + QPU, never N + QPU".
Phase 9 lessons (in phase7 §"Phase 9 lessons"):
1. Cycle-1 v4-pattern is the v1 starting point (saves 3 iterations)
2. Phase 5 review pays off every cycle
3. R isolation misleading on bandwidth-saturated hardware
4. Oversubscription tax depends on kernel weight
5. shaderdb 4-threads/0-spills = compute not the bottleneck
New artifacts:
- src/v3d_lpf_h_4_8.comp — GLSL kernel
- tests/bench_v3d_lpf.c — M1'' + M2'' harness with
contract asserts + fm/hev
pass-rate instrumentation
- tests/bench_concurrent_lpf.c — M4'' pthread bench
(mirrors bench_concurrent.c)
- docs/k2_deblock_phase{4,5,7}.md — plan + review + verification
Project verdict: continue. Cycle 3 candidates: MC interpolation
(multiply-heavy, stress V3D SMUL24), CDEF (AV1-only, different
neighborhood shape), or wd=8/wd=16 LPF variants. User to direct.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
186 lines
6.6 KiB
CMake
186 lines
6.6 KiB
CMake
# daedalus-fourier — Phase 3 baseline + (later) Phase 6 implementation.
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#
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# Builds:
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# bench_neon_idct — NEON throughput baseline (Phase 3 M3) +
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# bit-exact correctness gate (Phase 1 M1).
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# bench_vulkan_dispatch — Vulkan compute dispatch-overhead baseline (M5).
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#
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# Linkage note: bench_neon_idct statically links the vendored
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# FFmpeg n7.1.3 NEON snapshot (LGPL-2.1+); see
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# external/ffmpeg-snapshot/PROVENANCE.md.
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cmake_minimum_required(VERSION 3.20)
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project(daedalus-fourier C ASM)
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set(CMAKE_C_STANDARD 11)
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set(CMAKE_C_STANDARD_REQUIRED ON)
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if (NOT CMAKE_BUILD_TYPE)
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set(CMAKE_BUILD_TYPE Release)
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endif()
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if (NOT CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64")
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message(FATAL_ERROR
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"daedalus-fourier targets aarch64 (Pi 5 / BCM2712). "
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"Cross-compile not yet wired.")
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endif()
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add_compile_options(-Wall -Wextra -Wno-unused-parameter)
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# ---- Vendored FFmpeg snapshot (LGPL-2.1+) -----------------------------------
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set(FFSNAP ${CMAKE_SOURCE_DIR}/external/ffmpeg-snapshot)
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# Assembly preamble (config.h shim + FFmpeg's asm helpers) used by the
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# vendored .S file. -I flags expose:
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# - FFSNAP/ so `#include "config.h"` finds our shim
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# - FFSNAP/libavcodec/aarch64/ so `#include "neon.S"` finds the helper
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# - FFSNAP/ so `#include "libavutil/aarch64/asm.S"`
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# resolves against the vendored copy
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set(FFASM_FLAGS
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-I${FFSNAP}
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-I${FFSNAP}/libavcodec/aarch64
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-I${FFSNAP}
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)
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set(FFASM_SOURCES
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${FFSNAP}/libavcodec/aarch64/vp9itxfm_neon.S
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)
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# Cycle 2 — VP9 loop filter NEON source (vendored 2026-05-18).
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set(FFASM_LPF_SOURCES
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${FFSNAP}/libavcodec/aarch64/vp9lpf_neon.S
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)
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set_source_files_properties(${FFASM_LPF_SOURCES} PROPERTIES
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COMPILE_OPTIONS "${FFASM_FLAGS}"
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LANGUAGE ASM)
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# Tell CMake/gas to preprocess .S sources.
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set_source_files_properties(${FFASM_SOURCES} PROPERTIES
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COMPILE_OPTIONS "${FFASM_FLAGS}"
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LANGUAGE ASM)
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# ---- NEON baseline microbenches --------------------------------------------
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add_executable(bench_neon_idct
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tests/bench_neon_idct.c
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tests/vp9_idct8_ref.c
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${FFASM_SOURCES}
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)
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target_compile_options(bench_neon_idct PRIVATE -O3 -march=armv8-a+simd)
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# Cycle 2 — VP9 loop filter NEON baseline.
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add_executable(bench_neon_lpf
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tests/bench_neon_lpf.c
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tests/vp9_lpf_ref.c
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${FFASM_LPF_SOURCES}
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)
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target_compile_options(bench_neon_lpf PRIVATE -O3 -march=armv8-a+simd)
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# bench_neon_idct doesn't need vulkan/drm — pure CPU baseline.
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# ---- Vulkan dispatch-overhead microbench (next chunk) ----------------------
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# Stub: written in a follow-up step. Toggle ON with -DDAEDALUS_BUILD_VULKAN=ON
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# once tests/bench_vulkan_dispatch.c exists.
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option(DAEDALUS_BUILD_VULKAN "Build Vulkan compute-dispatch microbench" ON)
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if (DAEDALUS_BUILD_VULKAN)
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find_package(Vulkan REQUIRED)
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# Compile GLSL compute shaders to SPIR-V via glslangValidator.
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# The binary loads them at runtime from the build dir (cwd-relative).
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find_program(GLSLANG_VALIDATOR
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NAMES glslangValidator glslang
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REQUIRED)
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set(NOOP_SPV ${CMAKE_BINARY_DIR}/noop.spv)
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add_custom_command(
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OUTPUT ${NOOP_SPV}
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COMMAND ${GLSLANG_VALIDATOR} -V -o ${NOOP_SPV}
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${CMAKE_SOURCE_DIR}/tests/shaders/noop.comp
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DEPENDS ${CMAKE_SOURCE_DIR}/tests/shaders/noop.comp
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COMMENT "glslang: noop.comp -> noop.spv"
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VERBATIM
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)
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set(IDCT8_SPV ${CMAKE_BINARY_DIR}/v3d_idct8.spv)
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add_custom_command(
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OUTPUT ${IDCT8_SPV}
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COMMAND ${GLSLANG_VALIDATOR} -V --target-env vulkan1.3
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-o ${IDCT8_SPV}
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${CMAKE_SOURCE_DIR}/src/v3d_idct8.comp
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DEPENDS ${CMAKE_SOURCE_DIR}/src/v3d_idct8.comp
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COMMENT "glslang: v3d_idct8.comp -> v3d_idct8.spv"
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VERBATIM
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)
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set(LPF_SPV ${CMAKE_BINARY_DIR}/v3d_lpf_h_4_8.spv)
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add_custom_command(
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OUTPUT ${LPF_SPV}
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COMMAND ${GLSLANG_VALIDATOR} -V --target-env vulkan1.3
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-o ${LPF_SPV}
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${CMAKE_SOURCE_DIR}/src/v3d_lpf_h_4_8.comp
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DEPENDS ${CMAKE_SOURCE_DIR}/src/v3d_lpf_h_4_8.comp
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COMMENT "glslang: v3d_lpf_h_4_8.comp -> v3d_lpf_h_4_8.spv"
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VERBATIM
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)
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add_custom_target(daedalus_shaders ALL DEPENDS ${NOOP_SPV} ${IDCT8_SPV} ${LPF_SPV})
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# v3d_runner — reusable Vulkan plumbing.
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add_library(v3d_runner STATIC src/v3d_runner.c)
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target_include_directories(v3d_runner PUBLIC src)
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target_link_libraries(v3d_runner PUBLIC Vulkan::Vulkan)
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target_compile_options(v3d_runner PRIVATE -O2)
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add_executable(bench_vulkan_dispatch tests/bench_vulkan_dispatch.c)
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add_dependencies(bench_vulkan_dispatch daedalus_shaders)
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target_link_libraries(bench_vulkan_dispatch PRIVATE Vulkan::Vulkan)
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target_compile_options(bench_vulkan_dispatch PRIVATE -O2)
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add_executable(bench_v3d_idct
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tests/bench_v3d_idct.c
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tests/vp9_idct8_ref.c
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)
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add_dependencies(bench_v3d_idct daedalus_shaders)
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target_link_libraries(bench_v3d_idct PRIVATE v3d_runner Vulkan::Vulkan)
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target_compile_options(bench_v3d_idct PRIVATE -O2)
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# Cycle 2 — QPU LPF bench.
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add_executable(bench_v3d_lpf
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tests/bench_v3d_lpf.c
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tests/vp9_lpf_ref.c
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)
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add_dependencies(bench_v3d_lpf daedalus_shaders)
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target_link_libraries(bench_v3d_lpf PRIVATE v3d_runner Vulkan::Vulkan)
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target_compile_options(bench_v3d_lpf PRIVATE -O2)
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# M4 — concurrent CPU(NEON) + QPU bench. Links the FFmpeg NEON
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# snapshot so we can run real NEON kernels on pinned CPU cores
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# while the QPU runs its dispatch loop concurrently.
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add_executable(bench_concurrent
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tests/bench_concurrent.c
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${FFASM_SOURCES}
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)
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add_dependencies(bench_concurrent daedalus_shaders)
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target_link_libraries(bench_concurrent PRIVATE v3d_runner Vulkan::Vulkan pthread)
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target_compile_options(bench_concurrent PRIVATE -O3 -march=armv8-a+simd)
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# Cycle 2 M4'' — concurrent LPF.
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add_executable(bench_concurrent_lpf
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tests/bench_concurrent_lpf.c
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${FFASM_LPF_SOURCES}
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)
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add_dependencies(bench_concurrent_lpf daedalus_shaders)
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target_link_libraries(bench_concurrent_lpf PRIVATE v3d_runner Vulkan::Vulkan pthread)
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target_compile_options(bench_concurrent_lpf PRIVATE -O3 -march=armv8-a+simd)
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endif()
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# ---- Summary ----------------------------------------------------------------
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message(STATUS "daedalus-fourier build configured for ${CMAKE_SYSTEM_PROCESSOR}")
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message(STATUS " FFmpeg snapshot: ${FFSNAP}")
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message(STATUS " Build type: ${CMAKE_BUILD_TYPE}")
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message(STATUS " Targets: bench_neon_idct"
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"$<$<BOOL:${DAEDALUS_BUILD_VULKAN}>:; bench_vulkan_dispatch>")
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