Cycle 3 (MC interpolation) closure: M1'''=100%, R'''=0.067 RED, M4=-19.5%
Third daedalus-fourier kernel — VP9 8-tap regular subpel filter,
horizontal direction, 8-wide output. Multiply-heavy by design to
stress V3D's no-DP4A deficit. Full cycle Phase 1-7 + M4'''.
Phase 5''' second-model review delivered cleanly — caught 1 RED
bug pre-implementation (src_off off-by-3 indexing convention) and
2 YELLOW gaps (assert MUST language, shaderdb filter-LUT gate).
Without the review, M1''' would have failed silently on first run
with cryptic "high-index source pixels wrong" symptoms.
Phase 6 v1 first-light: M1''' 100.0000% bit-exact (65536/65536
blocks across all 16 mx phases). Phase 5''' filter-LUT prediction
materialised exactly: 197 uniforms (gate was 144), 2 threads (down
from cycle-2's 4 due to register pressure).
Performance:
M2''' = 1.413 Mblock/s (707.9 ns/block)
M3''' = 20.997 Mblock/s (NEON baseline phase3)
R''' = 0.067 (RED band — structural mismatch)
shaderdb: 488 inst, 2 threads, 197 uniforms, 25 max-temps, 0 spills
M4''' concurrent matrix (8s windows):
NEON 1-core 14.479 Mblock/s
NEON 4-core 15.248 Mblock/s <- baseline (compute-bound,
not bandwidth-saturated
like cycles 1+2!)
QPU only 1.380 Mblock/s
MIXED NEON-3 + QPU 12.277 Mblock/s <- -19.5% (FAIL gate)
MIXED NEON-4 + QPU 12.158 Mblock/s <- -20.3%
NEW cross-cycle finding (Phase 9 lesson 2): compute-bound CPU
workloads make the QPU-offload story collapse. Cycles 1+2 were
bandwidth-saturated (4-core scaling 0.56-0.82x of 1-core), so
freeing a CPU core via QPU offload added throughput. Cycle 3 MC
is compute-bound (4-core scaling 1.05x of 1-core — near-linear),
no free cycles to free. QPU contribution (0.45 Mblock/s in
contention) doesn't compensate for losing 1 NEON core delivering
~3.8 Mblock/s.
But 30fps@1080p floor: PASS in every config (1.4x to 15.7x
isolation margin). Per project_30fps_floor_is_fine.md, user-facing
test never fails — daily YouTube playback works fine on any CPU/QPU
split.
DEPLOYMENT RECIPE for higgs (cycle 3 confirmed split):
IDCT (k1) -> QPU (R=0.92, +7% mixed, frees CPU core)
LPF (k2) -> QPU (R=0.41, +7% mixed, frees CPU core)
MC (k3) -> CPU (R=0.067, -19.5% mixed — stays on CPU)
Entropy -> CPU (structurally serial)
Mixed-substrate deployment, not "QPU does everything". Realistic for
higgs: entropy + MC on 2-3 ARM cores; IDCT + LPF dispatched to QPU
concurrently; 1-2 ARM cores left for vscode etc.
New artifacts:
- src/v3d_mc_8h.comp — GLSL kernel
- tests/vp9_mc_ref.c — standalone C ref (REGULAR filter
embedded; clean transcription)
- tests/bench_neon_mc.c — M1'''_c + M3''' bench
- tests/bench_v3d_mc.c — M1''' + M2''' bench with contract
asserts + 30fps margin display
- tests/bench_concurrent_mc.c — M4''' pthread bench
- external/ffmpeg-snapshot/libavcodec/aarch64/vp9mc_neon.S (vendored)
- external/ffmpeg-snapshot/libavcodec/vp9_subpel_filters_table.c
(hand-extracted; provides
ff_vp9_subpel_filters symbol
without dragging in full vp9dsp.c)
- docs/k3_mc_phase{1,2,3,4,5,7}.md — full cycle documentation
Memory updates: project_30fps_floor_is_fine.md (user's 30fps target
recalibration), MEMORY.md index updated.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
@@ -0,0 +1,286 @@
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/*
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* Cycle 3 M4''' — concurrent CPU(NEON MC) + QPU(V3D MC) throughput.
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* Same pthread/barrier pattern as bench_concurrent{,_lpf}.c.
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* License: BSD-2-Clause.
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <stddef.h>
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#include <time.h>
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#include <getopt.h>
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#include <pthread.h>
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#include <sched.h>
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#include <assert.h>
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#include <vulkan/vulkan.h>
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#include "v3d_runner.h"
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extern void ff_vp9_put_regular8_h_neon(
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uint8_t *dst, ptrdiff_t dst_stride,
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const uint8_t *src, ptrdiff_t src_stride,
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int h, int mx, int my);
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#define SRC_W 16
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#define DST_W 8
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#define SRC_H 8
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#define DST_H 8
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#define SRC_BYTES (SRC_H * SRC_W)
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#define DST_BYTES (DST_H * DST_W)
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static inline uint64_t xs_step(uint64_t *s) {
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uint64_t x = *s; x ^= x << 13; x ^= x >> 7; x ^= x << 17; return *s = x;
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}
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static uint64_t xs_init(uint64_t s) { return s ? s : 0xa57edbeef5717ULL; }
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static double now_s(void) {
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struct timespec t; clock_gettime(CLOCK_MONOTONIC_RAW, &t);
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return t.tv_sec + t.tv_nsec * 1e-9;
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}
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static volatile int g_stop = 0;
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static pthread_barrier_t g_start;
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/* --- NEON worker ----------- */
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#define NEON_BATCH 8192
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typedef struct {
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int worker_id, affinity_core;
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uint64_t blocks_done;
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double elapsed_s;
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} neon_args;
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static void *neon_worker(void *p)
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{
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neon_args *a = p;
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cpu_set_t cs; CPU_ZERO(&cs); CPU_SET(a->affinity_core, &cs);
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pthread_setaffinity_np(pthread_self(), sizeof(cs), &cs);
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uint64_t s = xs_init((uint64_t) a->worker_id * 0xc01dbeefULL);
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uint8_t *master = malloc((size_t) NEON_BATCH * SRC_BYTES);
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uint8_t *work = malloc((size_t) NEON_BATCH * SRC_BYTES);
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uint8_t *dsts = malloc((size_t) NEON_BATCH * DST_BYTES);
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int *mxs = malloc(NEON_BATCH * sizeof(int));
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for (int i = 0; i < NEON_BATCH; i++) {
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for (int j = 0; j < SRC_BYTES; j++)
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master[(size_t)i * SRC_BYTES + j] = (uint8_t)(xs_step(&s) & 0xff);
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mxs[i] = (int)(xs_step(&s) & 15);
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}
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pthread_barrier_wait(&g_start);
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double t0 = now_s();
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uint64_t done = 0;
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while (!g_stop) {
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memcpy(work, master, (size_t) NEON_BATCH * SRC_BYTES);
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for (int i = 0; i < NEON_BATCH; i++)
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ff_vp9_put_regular8_h_neon(
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dsts + (size_t)i * DST_BYTES, DST_W,
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work + (size_t)i * SRC_BYTES + 3, SRC_W,
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DST_H, mxs[i], 0);
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done += NEON_BATCH;
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}
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a->elapsed_s = now_s() - t0;
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a->blocks_done = done;
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free(master); free(work); free(dsts); free(mxs);
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return NULL;
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}
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/* --- QPU worker ----------- */
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typedef struct {
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int affinity_core, n_blocks;
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uint64_t blocks_done;
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double elapsed_s;
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} qpu_args;
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typedef struct {
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uint32_t n_blocks, dst_stride_u8, src_stride_u8, _pad;
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} push_consts;
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static void *qpu_worker(void *p)
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{
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qpu_args *a = p;
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cpu_set_t cs; CPU_ZERO(&cs); CPU_SET(a->affinity_core, &cs);
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pthread_setaffinity_np(pthread_self(), sizeof(cs), &cs);
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v3d_runner *r = v3d_runner_create();
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if (!r) return NULL;
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int n_blocks = a->n_blocks;
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size_t meta_bytes = (size_t) n_blocks * 4 * sizeof(uint32_t);
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size_t src_bytes = (size_t) n_blocks * SRC_BYTES;
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size_t dst_bytes = (size_t) n_blocks * DST_BYTES;
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v3d_buffer buf_meta = {0}, buf_dst = {0}, buf_src = {0};
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v3d_runner_create_buffer(r, meta_bytes, &buf_meta);
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v3d_runner_create_buffer(r, dst_bytes, &buf_dst);
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v3d_runner_create_buffer(r, src_bytes, &buf_src);
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uint64_t s = 0xfeedfacecafebabeULL;
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uint8_t *master = malloc(src_bytes);
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for (size_t i = 0; i < src_bytes; i++) master[i] = (uint8_t)(xs_step(&s) & 0xff);
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memcpy(buf_src.mapped, master, src_bytes);
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uint32_t *meta = buf_meta.mapped;
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assert(DST_W >= 8); assert(SRC_W >= 15);
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for (int i = 0; i < n_blocks; i++) {
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meta[4*i + 0] = (uint32_t)((size_t)i * DST_BYTES); /* dst_off */
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meta[4*i + 1] = (uint32_t)((size_t)i * SRC_BYTES); /* src_off (RAW, no +3) */
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meta[4*i + 2] = (uint32_t)(xs_step(&s) & 15); /* mx */
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meta[4*i + 3] = 0;
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}
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v3d_pipeline pipe = {0};
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v3d_runner_create_pipeline(r, "v3d_mc_8h.spv", 3, sizeof(push_consts), &pipe);
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v3d_buffer bufs[3] = { buf_meta, buf_dst, buf_src };
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v3d_runner_bind_buffers(r, &pipe, bufs, 3);
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const uint32_t bpw = 32;
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uint32_t gc = (uint32_t)((n_blocks + bpw - 1) / bpw);
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push_consts pc = { .n_blocks = (uint32_t) n_blocks,
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.dst_stride_u8 = DST_W,
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.src_stride_u8 = SRC_W };
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VkCommandBuffer cb = v3d_runner_alloc_cmdbuf(r);
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VkCommandBufferBeginInfo cbbi = { .sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO };
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vkBeginCommandBuffer(cb, &cbbi);
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vkCmdBindPipeline(cb, VK_PIPELINE_BIND_POINT_COMPUTE, pipe.pipeline);
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vkCmdBindDescriptorSets(cb, VK_PIPELINE_BIND_POINT_COMPUTE,
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pipe.layout, 0, 1, &pipe.desc_set, 0, NULL);
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vkCmdPushConstants(cb, pipe.layout, VK_SHADER_STAGE_COMPUTE_BIT,
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0, sizeof(pc), &pc);
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vkCmdDispatch(cb, gc, 1, 1);
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vkEndCommandBuffer(cb);
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for (int i = 0; i < 5; i++) v3d_runner_submit_wait(r, cb);
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pthread_barrier_wait(&g_start);
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double t0 = now_s();
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uint64_t done = 0;
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while (!g_stop) {
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memset(buf_dst.mapped, 0, dst_bytes);
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v3d_runner_submit_wait(r, cb);
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done += n_blocks;
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}
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a->elapsed_s = now_s() - t0;
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a->blocks_done = done;
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free(master);
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v3d_runner_destroy_pipeline(r, &pipe);
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v3d_runner_destroy_buffer(r, &buf_src);
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v3d_runner_destroy_buffer(r, &buf_dst);
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v3d_runner_destroy_buffer(r, &buf_meta);
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v3d_runner_destroy(r);
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return NULL;
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}
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typedef struct { double duration_s; } timer_args;
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static void *timer_thread(void *p) {
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timer_args *a = p;
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pthread_barrier_wait(&g_start);
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double end = now_s() + a->duration_s;
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while (now_s() < end) {
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struct timespec ts = {0, 1000000}; nanosleep(&ts, NULL);
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}
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g_stop = 1;
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return NULL;
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}
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enum mode { MODE_NEON, MODE_QPU, MODE_MIXED };
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int main(int argc, char **argv)
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{
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enum mode mode = MODE_NEON;
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int n_neon = 4, qpu_core = 3, qpu_n_blocks = 65536;
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double duration = 8.0;
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static struct option opts[] = {
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{"mode", required_argument, 0, 'm'},
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{"neon-threads", required_argument, 0, 'n'},
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{"qpu-core", required_argument, 0, 'c'},
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{"qpu-blocks", required_argument, 0, 'b'},
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{"duration", required_argument, 0, 'd'},
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{0,0,0,0}
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};
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for (int c; (c = getopt_long(argc, argv, "m:n:c:b:d:", opts, 0)) != -1;) {
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switch (c) {
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case 'm':
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if (!strcmp(optarg, "neon-only")) mode = MODE_NEON;
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else if (!strcmp(optarg, "qpu-only")) mode = MODE_QPU;
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else if (!strcmp(optarg, "mixed")) mode = MODE_MIXED;
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else { fprintf(stderr, "bad mode\n"); return 2; }
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break;
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case 'n': n_neon = atoi(optarg); break;
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case 'c': qpu_core = atoi(optarg); break;
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case 'b': qpu_n_blocks = atoi(optarg); break;
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case 'd': duration = atof(optarg); break;
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default: return 2;
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}
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}
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int has_qpu = (mode == MODE_QPU || mode == MODE_MIXED);
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int has_neon = (mode == MODE_NEON || mode == MODE_MIXED);
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int n_workers = (has_neon ? n_neon : 0) + (has_qpu ? 1 : 0);
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int barrier_count = n_workers + 1 + 1;
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printf("=== M4''' concurrent MC bench ===\n");
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printf(" mode: %s, neon: %d, qpu: core %d / %d blocks, %.1fs\n",
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mode == MODE_NEON ? "neon-only" : mode == MODE_QPU ? "qpu-only" : "mixed",
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has_neon ? n_neon : 0,
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has_qpu ? qpu_core : -1,
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has_qpu ? qpu_n_blocks : 0,
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duration);
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pthread_barrier_init(&g_start, NULL, barrier_count);
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pthread_t timer_tid; timer_args ta = { .duration_s = duration };
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pthread_create(&timer_tid, NULL, timer_thread, &ta);
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pthread_t neon_tids[16] = {0};
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neon_args n_args[16] = {0};
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if (has_neon) {
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for (int i = 0; i < n_neon; i++) {
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n_args[i] = (neon_args){ .worker_id = i, .affinity_core = i };
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pthread_create(&neon_tids[i], NULL, neon_worker, &n_args[i]);
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}
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}
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pthread_t qpu_tid = 0;
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qpu_args q_args = {0};
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if (has_qpu) {
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q_args = (qpu_args){ .affinity_core = qpu_core, .n_blocks = qpu_n_blocks };
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pthread_create(&qpu_tid, NULL, qpu_worker, &q_args);
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}
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pthread_barrier_wait(&g_start);
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pthread_join(timer_tid, NULL);
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if (has_neon) for (int i = 0; i < n_neon; i++) pthread_join(neon_tids[i], NULL);
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if (has_qpu) pthread_join(qpu_tid, NULL);
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uint64_t total = 0; double max_e = 0;
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if (has_neon) {
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printf("NEON per-thread:\n");
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for (int i = 0; i < n_neon; i++) {
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double mbs = n_args[i].blocks_done / n_args[i].elapsed_s / 1e6;
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printf(" core %d: %.3f Mblock/s\n", n_args[i].affinity_core, mbs);
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total += n_args[i].blocks_done;
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if (n_args[i].elapsed_s > max_e) max_e = n_args[i].elapsed_s;
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}
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}
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if (has_qpu) {
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double mbs = q_args.blocks_done / q_args.elapsed_s / 1e6;
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printf("QPU (core %d): %.3f Mblock/s\n", q_args.affinity_core, mbs);
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total += q_args.blocks_done;
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if (q_args.elapsed_s > max_e) max_e = q_args.elapsed_s;
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}
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double total_mbs = total / max_e / 1e6;
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printf("\n=== AGGREGATE ===\n");
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printf(" Mblock/s : %.3f\n", total_mbs);
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printf(" 30fps@1080p floor: 0.972 Mblock/s — %.1fx margin\n",
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total_mbs / 0.972);
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pthread_barrier_destroy(&g_start);
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return 0;
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}
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