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el/lang/runtime/eg_cosine_batch_strategy_metal_hand.m
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bigmerge b3f410fc91
El SDK CI - dev / build-and-test (pull_request) Failing after 4m29s
engram: batch-cosine Adapter/Strategy/Factory over ggml, supersedes hand-rolled PR #114
Stop hand-rolling GPU kernels for batch cosine similarity — use ggml (the
MIT-licensed compute library underneath llama.cpp, installed standalone via
Homebrew) as the preferred backend, without ripping out PR #114's
carefully-verified hand-rolled Metal shader.

Structure: one stable public adapter (eg_cosine_batch.h, zero #ifdef at call
sites) backed by three selectable concrete Strategies behind an internal
vtable (eg_cosine_batch_strategy.h) chosen by a Factory (eg_cosine_batch.c):

  - eg_cosine_batch_strategy_ggml.c    — NEW. ggml + dynamically-loaded Metal
                                          backend plugin (ggml_backend_load_all_from_path
                                          + ggml_mul_mat for the batched dot
                                          product), gather/scatter around the
                                          -2.0 sentinel contract.
  - eg_cosine_batch_strategy_metal_hand.m — PR #114's original hand-rolled
                                          Metal shader bridge, preserved
                                          almost verbatim, now one strategy
                                          among several rather than the only
                                          option. eg_cosine_batch.metal kept
                                          byte-identical to the original.
  - eg_cosine_batch_strategy_cpu.c     — universal always-false fallback
                                          (direct descendant of PR #114's
                                          eg_metal_cosine_stub.c).

Selection: EL_COSINE_BATCH_STRATEGY=ggml|metal|cpu|auto (default: ggml first,
then hand-rolled Metal, then CPU — first available wins), plus back-compat
EL_METAL_COSINE=0 to disable every GPU-backed strategy. build_vindex_bench.sh
compiles all three strategies on Darwin, CPU-fallback-only elsewhere.

vindex_bench.c now reports BRUTE-GGML and BRUTE-METAL side by side against
the same CPU oracle, on the same dataset, in one run (real numbers vs. real
store snapshot in the PR body).
2026-08-15 17:16:41 -05:00

359 lines
17 KiB
Objective-C

/* eg_cosine_batch_strategy_metal_hand.m — the HAND-ROLLED-METAL Strategy.
*
* This is PR #114's original Objective-C bridge (formerly eg_metal_cosine.m)
* exposing the hand-written Metal compute shader (eg_cosine_batch.metal) as
* one concrete EgCosineBatchStrategy. It is preserved here almost verbatim —
* real, carefully verified work, not discarded — now living behind the
* Adapter/Strategy/Factory restructuring (see eg_cosine_batch.h and
* eg_cosine_batch_strategy.h) alongside the new ggml-Metal strategy
* (eg_cosine_batch_strategy_ggml.c) and the universal CPU fallback
* (eg_cosine_batch_strategy_cpu.c). The factory in eg_cosine_batch.c prefers
* ggml by default when both are available; this strategy remains selectable
* via EL_COSINE_BATCH_STRATEGY=metal, and is what the factory falls back to
* if ggml's backend plugin fails to load/init for any reason.
*
* Apple-only (Metal has no other platform). This file is excluded from the
* build entirely on non-Darwin — see build_vindex_bench.sh, which only
* compiles/links this file and defines EG_HAVE_STRATEGY_METAL_HAND when
* `uname` is Darwin. On Linux the factory never sees this strategy at all —
* callers must always be prepared for the "no real strategy available"
* fallback via the CPU strategy, which is also exactly what happens here on
* Apple hardware with no usable GPU.
*
* Design (unchanged from PR #114):
* - Device/queue/pipeline are created lazily, once, and cached in static
* globals — every call after the first only allocates buffers + submits.
* - The Metal shader source is embedded as a C string literal (kMetalSrc
* below) rather than loaded from a file at runtime or shipped as a
* precompiled .metallib. Chosen over newLibraryWithFile: /a .metallib
* because the engram binary can be invoked from an arbitrary working
* directory (launchd job, nsbx sandbox, CI) and a file-path shader would
* be one relocation away from silently falling back to CPU for reasons
* that have nothing to do with Metal availability. Embedding costs one
* runtime shader compile (~tens of ms) on first use, amortized over the
* process lifetime, in exchange for a genuinely self-contained binary.
* Source of truth for review/tooling is eg_cosine_batch.metal — this
* string MUST be kept byte-identical to that file (a comment marks both
* ends of the copy).
* - Buffers use MTLResourceStorageModeShared: on Apple Silicon's unified
* memory, CPU and GPU read the same physical pages, so filling a buffer
* is a plain memcpy and there is no separate "upload" step.
* - ANY failure at ANY step (no device, pipeline compile error, buffer
* allocation failure, bad args) returns false and leaves out_scores
* untouched. This function is called from the request-handling hot path
* of a long-lived daemon — it must never throw, crash, or hang it.
*/
#import <Foundation/Foundation.h>
#import <Metal/Metal.h>
#include "eg_cosine_batch_strategy.h"
#include <string.h>
#include <stdlib.h>
/* ── BEGIN embedded shader source (keep in sync with eg_cosine_batch.metal) ── */
static const char* kEgCosineBatchMetalSrc =
"#include <metal_stdlib>\n"
"using namespace metal;\n"
"struct EgCosineParams { uint n; uint dim; };\n"
"kernel void eg_cosine_batch_kernel(\n"
" device const float* query [[buffer(0)]],\n"
" device const float* node_matrix [[buffer(1)]],\n"
" device const int* node_dims [[buffer(2)]],\n"
" constant EgCosineParams& p [[buffer(3)]],\n"
" device float* out_scores [[buffer(4)]],\n"
" uint gid [[thread_position_in_grid]])\n"
"{\n"
" if (gid >= p.n) return;\n"
" if (node_dims[gid] != int(p.dim)) { out_scores[gid] = -2.0f; return; }\n"
" device const float* row = node_matrix + (uint64_t)gid * (uint64_t)p.dim;\n"
" float dot0 = 0.0f, dot1 = 0.0f, dot2 = 0.0f, dot3 = 0.0f;\n"
" float na0 = 0.0f, na1 = 0.0f, na2 = 0.0f, na3 = 0.0f;\n"
" float nb0 = 0.0f, nb1 = 0.0f, nb2 = 0.0f, nb3 = 0.0f;\n"
" uint d = 0;\n"
" uint dim4 = p.dim & ~3u;\n"
" for (; d < dim4; d += 4) {\n"
" float a0 = row[d], b0 = query[d];\n"
" float a1 = row[d+1], b1 = query[d+1];\n"
" float a2 = row[d+2], b2 = query[d+2];\n"
" float a3 = row[d+3], b3 = query[d+3];\n"
" dot0 += a0*b0; dot1 += a1*b1; dot2 += a2*b2; dot3 += a3*b3;\n"
" na0 += a0*a0; na1 += a1*a1; na2 += a2*a2; na3 += a3*a3;\n"
" nb0 += b0*b0; nb1 += b1*b1; nb2 += b2*b2; nb3 += b3*b3;\n"
" }\n"
" float dot = (dot0 + dot1) + (dot2 + dot3);\n"
" float na = (na0 + na1) + (na2 + na3);\n"
" float nb = (nb0 + nb1) + (nb2 + nb3);\n"
" for (; d < p.dim; d++) {\n"
" float a = row[d], b = query[d];\n"
" dot += a*b; na += a*a; nb += b*b;\n"
" }\n"
" if (na <= 0.0f || nb <= 0.0f) { out_scores[gid] = -2.0f; return; }\n"
" out_scores[gid] = dot / sqrt(na * nb);\n"
"}\n"
"struct EgCosineMultiParams { uint n; uint dim; uint nq; };\n"
"kernel void eg_cosine_batch_multi_kernel(\n"
" device const float* queries [[buffer(0)]],\n"
" device const float* node_matrix [[buffer(1)]],\n"
" device const int* node_dims [[buffer(2)]],\n"
" constant EgCosineMultiParams& p [[buffer(3)]],\n"
" device float* out_scores [[buffer(4)]],\n"
" uint2 gid [[thread_position_in_grid]])\n"
"{\n"
" uint nid = gid.x, qid = gid.y;\n"
" if (nid >= p.n || qid >= p.nq) return;\n"
" uint64_t out_idx = (uint64_t)qid * (uint64_t)p.n + (uint64_t)nid;\n"
" if (node_dims[nid] != int(p.dim)) { out_scores[out_idx] = -2.0f; return; }\n"
" device const float* row = node_matrix + (uint64_t)nid * (uint64_t)p.dim;\n"
" device const float* query = queries + (uint64_t)qid * (uint64_t)p.dim;\n"
" float dot0 = 0.0f, dot1 = 0.0f, dot2 = 0.0f, dot3 = 0.0f;\n"
" float na0 = 0.0f, na1 = 0.0f, na2 = 0.0f, na3 = 0.0f;\n"
" float nb0 = 0.0f, nb1 = 0.0f, nb2 = 0.0f, nb3 = 0.0f;\n"
" uint d = 0;\n"
" uint dim4 = p.dim & ~3u;\n"
" for (; d < dim4; d += 4) {\n"
" float a0 = row[d], b0 = query[d];\n"
" float a1 = row[d+1], b1 = query[d+1];\n"
" float a2 = row[d+2], b2 = query[d+2];\n"
" float a3 = row[d+3], b3 = query[d+3];\n"
" dot0 += a0*b0; dot1 += a1*b1; dot2 += a2*b2; dot3 += a3*b3;\n"
" na0 += a0*a0; na1 += a1*a1; na2 += a2*a2; na3 += a3*a3;\n"
" nb0 += b0*b0; nb1 += b1*b1; nb2 += b2*b2; nb3 += b3*b3;\n"
" }\n"
" float dot = (dot0 + dot1) + (dot2 + dot3);\n"
" float na = (na0 + na1) + (na2 + na3);\n"
" float nb = (nb0 + nb1) + (nb2 + nb3);\n"
" for (; d < p.dim; d++) {\n"
" float a = row[d], b = query[d];\n"
" dot += a*b; na += a*a; nb += b*b;\n"
" }\n"
" if (na <= 0.0f || nb <= 0.0f) { out_scores[out_idx] = -2.0f; return; }\n"
" out_scores[out_idx] = dot / sqrt(na * nb);\n"
"}\n";
/* ── END embedded shader source ── */
typedef struct EgCosineParamsC { uint32_t n; uint32_t dim; } EgCosineParamsC;
typedef struct EgCosineMultiParamsC { uint32_t n; uint32_t dim; uint32_t nq; } EgCosineMultiParamsC;
static id<MTLDevice> g_device = nil;
static id<MTLCommandQueue> g_queue = nil;
static id<MTLComputePipelineState> g_pipeline = nil; /* single-query kernel */
static id<MTLComputePipelineState> g_pipeline_multi = nil; /* multi-query kernel */
static bool g_init_attempted = false;
static bool g_init_ok = false;
/* Lazy, one-time setup. Never throws — every Metal call here is the
* "returns nil/NSError on failure" flavor, not an exception-throwing one. */
static bool eg_metal_ensure_init(void) {
if (g_init_attempted) return g_init_ok;
g_init_attempted = true;
@autoreleasepool {
id<MTLDevice> dev = MTLCreateSystemDefaultDevice();
if (!dev) return false;
id<MTLCommandQueue> q = [dev newCommandQueue];
if (!q) return false;
NSError* err = nil;
NSString* src = [NSString stringWithUTF8String:kEgCosineBatchMetalSrc];
MTLCompileOptions* opts = [MTLCompileOptions new];
id<MTLLibrary> lib = [dev newLibraryWithSource:src options:opts error:&err];
if (!lib) return false;
id<MTLFunction> fn = [lib newFunctionWithName:@"eg_cosine_batch_kernel"];
if (!fn) return false;
id<MTLComputePipelineState> pipe = [dev newComputePipelineStateWithFunction:fn error:&err];
if (!pipe) return false;
id<MTLFunction> fnMulti = [lib newFunctionWithName:@"eg_cosine_batch_multi_kernel"];
if (!fnMulti) return false;
id<MTLComputePipelineState> pipeMulti = [dev newComputePipelineStateWithFunction:fnMulti error:&err];
if (!pipeMulti) return false;
g_device = dev;
g_queue = q;
g_pipeline = pipe;
g_pipeline_multi = pipeMulti;
g_init_ok = true;
return true;
}
}
static bool mh_available(void) {
return eg_metal_ensure_init();
}
static bool mh_batch(const float* query, int32_t qdim,
const float* const* node_ptrs,
const int32_t* node_dims,
int32_t n,
double* out_scores) {
if (!query || qdim <= 0 || !node_ptrs || !node_dims || n <= 0 || !out_scores) return false;
if (!eg_metal_ensure_init()) return false;
@autoreleasepool {
const size_t dim = (size_t)qdim;
const size_t nu = (size_t)n;
/* Gather into a packed row-major matrix — EngramNode.emb is one
* malloc per node, not a contiguous array, so this copy is
* unavoidable regardless of backend. Rows whose real dim doesn't
* match qdim are zero-filled (harmless: the kernel sentinels them
* via node_dims before ever reading the row). */
float* matrix = (float*)calloc(nu * dim, sizeof(float));
int32_t* dims_i32 = (int32_t*)malloc(nu * sizeof(int32_t));
if (!matrix || !dims_i32) { free(matrix); free(dims_i32); return false; }
for (size_t i = 0; i < nu; i++) {
dims_i32[i] = node_dims[i];
if (node_ptrs[i] && node_dims[i] == qdim) {
memcpy(matrix + i * dim, node_ptrs[i], dim * sizeof(float));
}
/* else: leave zero-filled; node_dims[i] != qdim (or missing)
* makes the kernel sentinel it to -2.0 without reading the row. */
}
id<MTLBuffer> bufQuery = [g_device newBufferWithBytes:query
length:dim * sizeof(float)
options:MTLResourceStorageModeShared];
id<MTLBuffer> bufMatrix = [g_device newBufferWithBytes:matrix
length:nu * dim * sizeof(float)
options:MTLResourceStorageModeShared];
id<MTLBuffer> bufDims = [g_device newBufferWithBytes:dims_i32
length:nu * sizeof(int32_t)
options:MTLResourceStorageModeShared];
EgCosineParamsC params = { (uint32_t)nu, (uint32_t)dim };
id<MTLBuffer> bufParams = [g_device newBufferWithBytes:&params
length:sizeof(params)
options:MTLResourceStorageModeShared];
id<MTLBuffer> bufOut = [g_device newBufferWithLength:nu * sizeof(float)
options:MTLResourceStorageModeShared];
free(matrix); free(dims_i32);
if (!bufQuery || !bufMatrix || !bufDims || !bufParams || !bufOut) return false;
id<MTLCommandBuffer> cmd = [g_queue commandBuffer];
if (!cmd) return false;
id<MTLComputeCommandEncoder> enc = [cmd computeCommandEncoder];
if (!enc) return false;
[enc setComputePipelineState:g_pipeline];
[enc setBuffer:bufQuery offset:0 atIndex:0];
[enc setBuffer:bufMatrix offset:0 atIndex:1];
[enc setBuffer:bufDims offset:0 atIndex:2];
[enc setBuffer:bufParams offset:0 atIndex:3];
[enc setBuffer:bufOut offset:0 atIndex:4];
NSUInteger tgSize = g_pipeline.maxTotalThreadsPerThreadgroup;
if (tgSize > 256) tgSize = 256;
if (tgSize < 1) tgSize = 1;
MTLSize gridSize = MTLSizeMake(nu, 1, 1);
MTLSize threadgroupSize = MTLSizeMake(tgSize, 1, 1);
[enc dispatchThreads:gridSize threadsPerThreadgroup:threadgroupSize];
[enc endEncoding];
[cmd commit];
[cmd waitUntilCompleted];
if (cmd.status != MTLCommandBufferStatusCompleted) return false;
const float* results = (const float*)bufOut.contents;
if (!results) return false;
for (size_t i = 0; i < nu; i++) out_scores[i] = (double)results[i];
return true;
}
}
static bool mh_batch_multi(const float* queries, int32_t qdim, int32_t nq,
const float* const* node_ptrs,
const int32_t* node_dims,
int32_t n,
double* out_scores) {
if (!queries || qdim <= 0 || nq <= 0 || !node_ptrs || !node_dims || n <= 0 || !out_scores) return false;
if (!eg_metal_ensure_init()) return false;
@autoreleasepool {
const size_t dim = (size_t)qdim;
const size_t nu = (size_t)n;
const size_t nqu = (size_t)nq;
float* matrix = (float*)calloc(nu * dim, sizeof(float));
int32_t* dims_i32 = (int32_t*)malloc(nu * sizeof(int32_t));
if (!matrix || !dims_i32) { free(matrix); free(dims_i32); return false; }
for (size_t i = 0; i < nu; i++) {
dims_i32[i] = node_dims[i];
if (node_ptrs[i] && node_dims[i] == qdim) {
memcpy(matrix + i * dim, node_ptrs[i], dim * sizeof(float));
}
}
/* This is the ONE upload of node_matrix for the whole nq-query batch —
* the fix for the measured re-upload-per-query slowdown. */
id<MTLBuffer> bufMatrix = [g_device newBufferWithBytes:matrix
length:nu * dim * sizeof(float)
options:MTLResourceStorageModeShared];
id<MTLBuffer> bufDims = [g_device newBufferWithBytes:dims_i32
length:nu * sizeof(int32_t)
options:MTLResourceStorageModeShared];
id<MTLBuffer> bufQueries = [g_device newBufferWithBytes:queries
length:nqu * dim * sizeof(float)
options:MTLResourceStorageModeShared];
EgCosineMultiParamsC params = { (uint32_t)nu, (uint32_t)dim, (uint32_t)nqu };
id<MTLBuffer> bufParams = [g_device newBufferWithBytes:&params
length:sizeof(params)
options:MTLResourceStorageModeShared];
id<MTLBuffer> bufOut = [g_device newBufferWithLength:nqu * nu * sizeof(float)
options:MTLResourceStorageModeShared];
free(matrix); free(dims_i32);
if (!bufMatrix || !bufDims || !bufQueries || !bufParams || !bufOut) return false;
id<MTLCommandBuffer> cmd = [g_queue commandBuffer];
if (!cmd) return false;
id<MTLComputeCommandEncoder> enc = [cmd computeCommandEncoder];
if (!enc) return false;
[enc setComputePipelineState:g_pipeline_multi];
[enc setBuffer:bufQueries offset:0 atIndex:0];
[enc setBuffer:bufMatrix offset:0 atIndex:1];
[enc setBuffer:bufDims offset:0 atIndex:2];
[enc setBuffer:bufParams offset:0 atIndex:3];
[enc setBuffer:bufOut offset:0 atIndex:4];
/* 2D dispatch: x over nodes, y over queries. Threadgroup width picked
* from the pipeline's own limit, height fixed at 1 — nq is typically
* small (tens to low hundreds) relative to n (thousands+), so tiling
* the wide axis (n) is what matters for occupancy. */
NSUInteger tgWidth = g_pipeline_multi.maxTotalThreadsPerThreadgroup;
if (tgWidth > 256) tgWidth = 256;
if (tgWidth < 1) tgWidth = 1;
MTLSize gridSize = MTLSizeMake(nu, nqu, 1);
MTLSize threadgroupSize = MTLSizeMake(tgWidth, 1, 1);
[enc dispatchThreads:gridSize threadsPerThreadgroup:threadgroupSize];
[enc endEncoding];
[cmd commit];
[cmd waitUntilCompleted];
if (cmd.status != MTLCommandBufferStatusCompleted) return false;
const float* results = (const float*)bufOut.contents;
if (!results) return false;
for (size_t i = 0; i < nqu * nu; i++) out_scores[i] = (double)results[i];
return true;
}
}
static const EgCosineBatchStrategy g_metal_hand_strategy = {
.name = "metal-hand",
.available = mh_available,
.batch = mh_batch,
.batch_multi = mh_batch_multi,
};
const EgCosineBatchStrategy* eg_cosine_batch_strategy_metal_hand(void) {
return &g_metal_hand_strategy;
}