Files
llama.cpp/tools/tuning/fa-vec.cpp
T
2026-08-05 16:22:33 +08:00

555 lines
21 KiB
C++

#include "fa-vec.h"
#include "bench.h"
#include "ggml-backend.h"
#include "ggml-metal-tuning.h"
#include "ggml.h"
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <random>
#include <set>
#include <string>
#include <vector>
// GQA spec-decode shape: enough query heads to keep the GPU busy so the Q>1 K/V-reuse
// benefit is visible. nh KV heads, nr2 query heads each, nr3 batches.
static const int FA_NH = 4;
static const int FA_NR2 = 8;
static const int FA_NR3 = 1;
struct fa_shape {
int dk;
int dv;
int ne01; // query rows
int ne11; // KV length
ggml_type type_kv;
};
// mirrors test_flash_attn_ext::build_graph for the subset this tuner sweeps
// (mask=true, sinks=false, prec=F32, type_K==type_V, no permute)
static ggml_tensor * fa_build_graph(ggml_context * ctx, const fa_shape & s) {
const int64_t dk_padded = GGML_PAD(s.dk, ggml_blck_size(s.type_kv));
const int64_t dv_padded = GGML_PAD(s.dv, ggml_blck_size(s.type_kv));
ggml_tensor * q = ggml_new_tensor_4d(ctx, GGML_TYPE_F32, dk_padded, s.ne01, FA_NH * FA_NR2, FA_NR3);
ggml_set_name(q, "q");
// K/V are views of a 2x-tall parent, as they are of the KV cache in production
ggml_tensor * k0 = ggml_new_tensor_4d(ctx, s.type_kv, dk_padded, 2 * s.ne11, FA_NH, FA_NR3);
ggml_tensor * k = ggml_view_4d(ctx, k0, dk_padded, s.ne11, FA_NH, FA_NR3, k0->nb[1], k0->nb[2], k0->nb[3], 0);
ggml_set_name(k, "k");
ggml_tensor * v = nullptr;
if (dk_padded == 576 && dv_padded == 512) {
// MLA: the V cache is a sub-view of the K cache
v = ggml_view_4d(ctx, k, dv_padded, s.ne11, FA_NH, FA_NR3, k->nb[1], k->nb[2], k->nb[3], 0);
} else {
ggml_tensor * v0 = ggml_new_tensor_4d(ctx, s.type_kv, dv_padded, 2 * s.ne11, FA_NH, FA_NR3);
v = ggml_view_4d(ctx, v0, dv_padded, s.ne11, FA_NH, FA_NR3, v0->nb[1], v0->nb[2], v0->nb[3], 0);
}
ggml_set_name(v, "v");
ggml_tensor * m = ggml_new_tensor_4d(ctx, GGML_TYPE_F16, s.ne11, s.ne01, 1, FA_NR3);
ggml_set_name(m, "m");
ggml_tensor * out = ggml_flash_attn_ext(ctx, q, k, v, m, 1.0f / sqrtf((float) s.dk), 0.0f, 0.0f);
ggml_flash_attn_ext_set_prec(out, GGML_PREC_F32);
ggml_set_name(out, "out");
return out;
}
static uint64_t fa_op_flops(const fa_shape & s) {
// Q*K^T is ne01 x dk x ne11, P*V is ne01 x ne11 x dv, per head
return (uint64_t) 2 * FA_NH * FA_NR2 * s.ne01 * (s.dk + s.dv) * s.ne11 * FA_NR3;
}
static void fa_init_uniform(ggml_tensor * t, std::mt19937 & rng, float min, float max) {
const size_t nels = ggml_nelements(t);
std::vector<float> data(nels);
std::uniform_real_distribution<float> dist(min, max);
for (size_t i = 0; i < nels; i++) {
data[i] = dist(rng);
}
if (t->type == GGML_TYPE_F32) {
ggml_backend_tensor_set(t, data.data(), 0, nels * sizeof(float));
return;
}
GGML_ASSERT(ggml_is_quantized(t->type) || t->type == GGML_TYPE_F16 || t->type == GGML_TYPE_BF16);
GGML_ASSERT(nels % ggml_blck_size(t->type) == 0);
std::vector<float> imatrix(t->ne[0], 1.0f);
const float * im = imatrix.data();
if (!ggml_quantize_requires_imatrix(t->type)) {
// when the imatrix is optional, exercise both paths; pick via one of the random numbers
if (data[0] > 0.5f * (min + max)) {
im = nullptr;
}
}
const size_t blck_size = ggml_blck_size(t->type);
const size_t n_blocks = nels / blck_size;
std::vector<uint8_t> dataq(ggml_row_size(t->type, nels));
ggml_quantize_chunk(t->type, data.data(), dataq.data(), 0, n_blocks, blck_size, im);
ggml_backend_tensor_set(t, dataq.data(), 0, dataq.size());
}
// mirrors init_tensor_kq_mask: f16 mask with ~20% of its blocks set to -INF or zero.
// the -INF blocks are what drives the kernel's skip-INF path, so this pattern is
// load-bearing for the timings, not just for numerics.
static void fa_init_kq_mask(ggml_tensor * t, std::mt19937 & rng, float min, float max) {
GGML_ASSERT(t->type == GGML_TYPE_F16);
const int32_t ne0 = (int32_t) t->ne[0];
const int32_t ne1 = (int32_t) t->ne[1];
const int32_t ne2 = (int32_t) t->ne[2];
const int32_t ne3 = (int32_t) t->ne[3];
std::vector<float> data_f32(size_t(ne0) * ne1 * ne2 * ne3);
std::vector<ggml_fp16_t> data_f16(size_t(ne0) * ne1 * ne2 * ne3);
std::uniform_real_distribution<float> dis(min, max);
for (size_t i = 0; i < data_f32.size(); i++) {
data_f32[i] = dis(rng);
}
const int blck0 = 128;
const int blck1 = 64;
const int n_inf_zero_blocks = 0.2 * (ne0 * ne1 * ne2 * ne3) / (blck0 * blck1);
for (int b = 0; b < n_inf_zero_blocks; b++) {
const int p3 = (int) (rng() % ne3);
const int p2 = (int) (rng() % ne2);
const int p1 = (int) (rng() % ne1);
const int p0 = (int) (rng() % ne0);
const bool inf = rng() & 1;
for (int i1 = 0; i1 < blck1 && p1 + i1 < ne1; i1++) {
const int idx = p3 * ne2 * ne1 * ne0 + p2 * ne1 * ne0 + (p1 + i1) * ne0 + p0;
for (int i0 = 0; i0 < blck0 && p0 + i0 < ne0; i0++) {
data_f32[idx + i0] = inf ? -INFINITY : 0.0f;
}
}
}
ggml_fp32_to_fp16_row(data_f32.data(), data_f16.data(), ne0 * ne1 * ne2 * ne3);
ggml_backend_tensor_set(t, data_f16.data(), 0, data_f16.size() * sizeof(ggml_fp16_t));
}
static unsigned fa_cell_seed(const fa_shape & s, unsigned base) {
unsigned h = base;
for (int v : { s.dk, s.dv, s.ne01, s.ne11, (int) s.type_kv }) {
h = h * 1000003u + (unsigned) v;
}
return h;
}
static void fa_init_tensors(ggml_context * ctx, const fa_shape & s, unsigned base_seed) {
std::mt19937 rng(fa_cell_seed(s, base_seed));
for (ggml_tensor * t = ggml_get_first_tensor(ctx); t != NULL; t = ggml_get_next_tensor(ctx, t)) {
if (t->view_src != NULL) {
continue; // views share their parent's data
}
if (strcmp(t->name, "m") == 0) {
fa_init_kq_mask(t, rng, -1.0f, 1.0f);
} else {
fa_init_uniform(t, rng, -1.0f, 1.0f);
}
}
}
using set_override_t = void (*)(int, int);
using clear_override_t = void (*)(void);
using bucket_t = int (*)(int64_t);
using baseline_ne_t = int (*)(int, int);
using device_token_t = const char * (*) (ggml_backend_dev_t);
struct fa_procs {
set_override_t set_ov = nullptr;
clear_override_t clr_ov = nullptr;
bucket_t ne11_bucket = nullptr;
bucket_t ne01_bucket = nullptr;
baseline_ne_t baseline_ne = nullptr;
device_token_t dev_token = nullptr;
bool ok() const { return set_ov && clr_ov && ne11_bucket && ne01_bucket && baseline_ne && dev_token; }
};
static fa_procs fa_resolve_procs(ggml_backend_dev_t dev) {
ggml_backend_reg_t reg = ggml_backend_dev_backend_reg(dev);
fa_procs p;
p.set_ov = (set_override_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_metal_tuning_set_fa_vec_override");
p.clr_ov =
(clear_override_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_metal_tuning_clear_fa_vec_override");
p.ne11_bucket = (bucket_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_metal_tuning_fa_vec_ne11_bucket");
p.ne01_bucket = (bucket_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_metal_tuning_fa_vec_ne01_bucket");
p.baseline_ne =
(baseline_ne_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_metal_tuning_fa_vec_baseline_ne");
p.dev_token = (device_token_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_metal_tuning_device_token");
return p;
}
static bool fa_filter_has(const char * filter, const char * name) {
if (!filter) {
return true;
}
const std::string f = std::string(",") + filter + ",";
return f.find(std::string(",") + name + ",") != std::string::npos;
}
struct fa_cand {
int Q, NE;
};
struct fa_point {
int dk, dv, ne11, ne01;
std::vector<double> t;
};
// base_i identifies the (Q=1, baseline NE) anchor configuration.
static std::vector<fa_cand> fa_build_cands(const fa_procs & procs, int dk, int dv, int & base_i) {
const int base_ne = procs.baseline_ne(dk, dv);
std::vector<fa_cand> cands;
base_i = -1;
for (int ne : ggml_metal_tuning::fa_vec_legal_ne(dk, dv)) {
for (int Q : { 1, 2, 4 }) {
if (Q == 1 && ne == base_ne) {
base_i = (int) cands.size();
}
cands.push_back({ Q, ne });
}
}
GGML_ASSERT(base_i >= 0);
return cands;
}
bool tuner_fa_vec_run(ggml_backend_t backend, ggml_backend_dev_t dev, const tuner_opts & opts) {
const fa_procs procs = fa_resolve_procs(dev);
if (!procs.ok()) {
fprintf(stderr, "error: metal fa_vec tuning procs unavailable\n");
return false;
}
const char * dev_token = procs.dev_token(dev);
struct shape_t {
int dk, dv;
};
const shape_t shapes[] = {
{ 32, 32 },
{ 64, 64 },
{ 96, 96 },
{ 128, 128 },
{ 192, 192 },
{ 192, 128 },
{ 256, 256 },
{ 320, 256 },
{ 512, 512 },
{ 576, 512 }
};
const int ne11_rep[] = { 512, 2048, 8192, 32768 }; // ne11 bucket representatives
const int ne01_rep[] = { 1, 2, 3, 4, 5, 6, 7, 8, 16 }; // point buckets (1-4) + tail mod-4 cycle + anchor
struct dtype_t {
ggml_type type;
const char * token;
};
const dtype_t dtypes[] = {
{ GGML_TYPE_F16, "GGML_TYPE_F16" },
{ GGML_TYPE_Q4_0, "GGML_TYPE_Q4_0" },
{ GGML_TYPE_Q4_1, "GGML_TYPE_Q4_1" },
{ GGML_TYPE_Q5_0, "GGML_TYPE_Q5_0" },
{ GGML_TYPE_Q5_1, "GGML_TYPE_Q5_1" },
{ GGML_TYPE_Q8_0, "GGML_TYPE_Q8_0" },
};
const double TUNE_TAU = 0.05; // max POINTWISE regret to ride a domain default
const double TUNE_THETA = 1.05; // min AGGREGATE bucket speedup vs baseline to tune at all
const cooldown_opts cool = {
opts.cooldown, opts.cool_drift, opts.cool_eps, opts.cool_max_wait, opts.cool_max_retry,
};
fprintf(stderr, "seed=%u reps=%d cooldown=%s (drift=%.2f eps=%.2f max_wait=%ds max_retry=%d)\n", opts.seed,
opts.reps, cool.enabled ? "on" : "off", cool.drift, cool.eps, cool.max_wait, cool.max_retry);
fprintf(stderr, "device token: %s\n", dev_token);
int n_untrusted = 0;
printf("// ==== BEGIN fa_vec_tuned_table rows (%s) ====\n", dev_token);
for (const auto & dtype : dtypes) {
const ggml_type type_kv = dtype.type;
if (!fa_filter_has(opts.dtype_filter, ggml_type_name(type_kv))) {
continue;
}
fprintf(stderr, "\n### dtype=%s\n", ggml_type_name(type_kv));
std::vector<fa_point> pts;
for (auto s : shapes) {
if (!fa_filter_has(opts.dk_filter, std::to_string(s.dk).c_str())) {
continue;
}
int base_i = 0;
std::vector<fa_cand> cands = fa_build_cands(procs, s.dk, s.dv, base_i);
for (int ne11 : ne11_rep) {
for (int ne01 : ne01_rep) {
const fa_shape sh = { s.dk, s.dv, ne01, ne11, type_kv };
perf_cell cell = build_perf_cell(
backend, [&](ggml_context * ctx) { return fa_build_graph(ctx, sh); },
[&](ggml_context * ctx) { fa_init_tensors(ctx, sh, opts.seed); },
[&](ggml_tensor *) { return fa_op_flops(sh); });
if (cell.gf == nullptr) {
continue;
}
// randomize candidate order to decorrelate thermal drift across the cell
std::vector<int> order((size_t) cands.size());
for (size_t i = 0; i < order.size(); ++i) {
order[i] = (int) i;
}
std::shuffle(order.begin(), order.end(), std::mt19937(opts.seed));
char label[128];
snprintf(label, sizeof(label), "dk=%d ne11=%d", s.dk, ne11);
cell_result r = measure_cell(
backend, cell, opts.reps, order, [&](int i) { procs.set_ov(cands[i].Q, cands[i].NE); },
[&]() { procs.clr_ov(); }, base_i, cool, label);
if (r.anchor_min > 0.0) {
fprintf(stderr, "# noise dk=%d dv=%d ne11=%d ne01=%d spread=%.1f%%\n", s.dk, s.dv, ne11, ne01,
100.0 * (r.anchor_max - r.anchor_min) / r.anchor_min);
}
if (!r.trusted) {
n_untrusted++;
fprintf(stderr, "# DROP untrusted cell dk=%d dv=%d ne11=%d ne01=%d\n", s.dk, s.dv, ne11, ne01);
continue;
}
int best_i = -1;
for (size_t i = 0; i < cands.size(); ++i) {
if (r.t[i] > 0.0 && (best_i < 0 || r.t[i] < r.t[best_i])) {
best_i = (int) i;
}
}
const double base_t = r.t[base_i];
const bool keep = best_i >= 0 && base_t > 0.0 && r.t[best_i] < base_t * 0.98;
fprintf(stderr, "# dtype=%s dk=%d dv=%d ne11=%d ne01=%d:", ggml_type_name(type_kv), s.dk, s.dv,
ne11, ne01);
for (size_t i = 0; i < cands.size(); ++i) {
fprintf(stderr, " Q%dNE%d=%.1f%s", cands[i].Q, cands[i].NE, r.t[i],
(int) i == best_i ? "*" : "");
}
if (keep) {
fprintf(stderr, " => Q%d,NE%d %.2fx\n", cands[best_i].Q, cands[best_i].NE,
base_t / r.t[best_i]);
} else {
fprintf(stderr, " => baseline\n");
}
pts.push_back({ s.dk, s.dv, ne11, ne01, r.t });
}
}
}
// compress into pasteable rows. per (dk,dv) and ne01 domain {decode==1, batch>=2},
// emit one ne11-collapsed default cfg (ne11_b=-1) plus a per-bucket exception wherever
// the default's pointwise regret vs the bucket target, or its aggregate slowdown vs
// baseline, exceeds TUNE_TAU.
std::vector<std::string> rows_out;
char rbuf[192];
for (auto s : shapes) {
if (!fa_filter_has(opts.dk_filter, std::to_string(s.dk).c_str())) {
continue;
}
int base_i = 0;
std::vector<fa_cand> cands = fa_build_cands(procs, s.dk, s.dv, base_i);
struct bkt_t {
int b11, b01, Ti;
std::vector<double> agg;
std::vector<const fa_point *> bp;
};
std::set<std::pair<int, int>> buckets;
for (int ne11 : ne11_rep) {
const int b11 = procs.ne11_bucket(ne11);
if (b11 == 0) {
continue;
}
for (int ne01 : ne01_rep) {
buckets.insert({ b11, procs.ne01_bucket(ne01) });
}
}
std::vector<bkt_t> bks;
for (const auto & bb : buckets) {
const int b11 = bb.first, b01 = bb.second;
std::vector<const fa_point *> bp;
for (const auto & p : pts) {
if (p.dk == s.dk && p.dv == s.dv && procs.ne11_bucket(p.ne11) == b11 &&
procs.ne01_bucket(p.ne01) == b01) {
bp.push_back(&p);
}
}
fprintf(stderr, "# bucket dk=%d dv=%d ne11_b=%d ne01_b=%d samples=%zu\n", s.dk, s.dv, b11, b01,
bp.size());
if (bp.empty()) {
fprintf(stderr, "# WARN empty bucket dk=%d dv=%d ne11_b=%d ne01_b=%d\n", s.dk, s.dv, b11, b01);
continue;
}
std::vector<double> agg(cands.size(), 0.0), worst(cands.size(), 0.0);
for (const auto * p : bp) {
double bestt = 0.0;
for (size_t i = 0; i < cands.size(); ++i) {
if (p->t[i] > 0.0 && (bestt == 0.0 || p->t[i] < bestt)) {
bestt = p->t[i];
}
}
for (size_t i = 0; i < cands.size(); ++i) {
agg[i] += p->t[i];
if (p->t[i] > 0.0 && bestt > 0.0) {
worst[i] = std::max(worst[i], p->t[i] / bestt);
}
}
}
int robust = 0;
for (size_t i = 1; i < cands.size(); ++i) {
if (worst[i] < worst[robust] || (worst[i] == worst[robust] && (cands[i].Q < cands[robust].Q ||
(cands[i].Q == cands[robust].Q &&
cands[i].NE < cands[robust].NE)))) {
robust = (int) i;
}
}
const bool tune = robust != base_i && agg[base_i] > 0.0 && agg[robust] > 0.0 &&
agg[base_i] / agg[robust] >= TUNE_THETA;
bks.push_back({ b11, b01, tune ? robust : base_i, agg, bp });
}
// pointwise regret of default cfg d vs the bucket target: a ratio-of-sums lets a
// default that wins on aligned ne01 hide a large penalty on a misaligned point
auto reg_pointwise = [&](const bkt_t * b, int d) {
double r = 0.0;
for (const auto * p : b->bp) {
const double td = p->t[d], tT = p->t[b->Ti];
if (td > 0.0 && tT > 0.0) {
r = std::max(r, td / tT - 1.0);
}
}
return r;
};
for (int dom = 0; dom <= 1; ++dom) { // 0 = decode (ne01==1), 1 = batch (ne01>=2)
std::vector<const bkt_t *> db;
for (const auto & b : bks) {
if ((dom == 0) == (b.b01 == 0)) {
db.push_back(&b);
}
}
if (db.empty()) {
continue;
}
// default cfg = the one minimizing (#rows, total achieved time, Q, NE)
int bestD = -1, bestRows = 1 << 30;
double bestTot = 0.0;
for (size_t d = 0; d < cands.size(); ++d) {
int rows = ((int) d != base_i) ? 1 : 0;
double tot = 0.0;
for (const auto * b : db) {
const double base_agg = b->agg[base_i];
const double reg = reg_pointwise(b, (int) d);
const double slow = base_agg > 0.0 ? b->agg[d] / base_agg - 1.0 : 0.0;
if (reg > TUNE_TAU || slow > TUNE_TAU) {
rows++;
tot += b->agg[b->Ti];
} else {
tot += b->agg[d];
}
}
const bool better =
bestD < 0 || rows < bestRows ||
(rows == bestRows &&
(tot < bestTot ||
(tot == bestTot && (cands[d].Q < cands[bestD].Q ||
(cands[d].Q == cands[bestD].Q && cands[d].NE < cands[bestD].NE)))));
if (better) {
bestD = (int) d;
bestRows = rows;
bestTot = tot;
}
}
if (bestD != base_i) {
snprintf(rbuf, sizeof(rbuf), " { { %s, %s, %d, %d, -1, %d }, { %d, %d } },", dev_token,
dtype.token, s.dk, s.dv, dom, cands[bestD].Q, cands[bestD].NE);
rows_out.emplace_back(rbuf);
}
for (const auto * b : db) {
const double base_agg = b->agg[base_i];
const double reg = reg_pointwise(b, bestD);
const double slow = base_agg > 0.0 ? b->agg[bestD] / base_agg - 1.0 : 0.0;
if (reg <= TUNE_TAU && slow <= TUNE_TAU) {
continue;
}
snprintf(rbuf, sizeof(rbuf), " { { %s, %s, %d, %d, %d, %d }, { %d, %d } },", dev_token,
dtype.token, s.dk, s.dv, b->b11, b->b01, cands[b->Ti].Q, cands[b->Ti].NE);
rows_out.emplace_back(rbuf);
}
}
}
printf("\n // ---- %s: %zu rows ----\n", ggml_type_name(type_kv), rows_out.size());
for (const auto & r : rows_out) {
printf("%s\n", r.c_str());
}
fflush(stdout);
}
printf("// ==== END fa_vec_tuned_table rows (%s) ====\n", dev_token);
if (n_untrusted > 0) {
fprintf(stderr, "\n%d cells excluded as untrusted (see DROP lines above)\n", n_untrusted);
}
return true;
}