url/colibri
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

feat(prefetch): implement prefetcher v2.1 with lookahead-2, hot pinning, adaptive cache, RMSNorm scaling, and routing EMA

Browse Source
This commit is contained in:
Egon Ruiter
2026-07-15 18:01:21 +02:00
parent 3fd47b7bbd
commit ac1f7a8f38
4 changed files with 536 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
c/olmoe.c
+344 -16
View File
@@ -5,6 +5,14 @@
* Densa (embed, attn, router, norme, lm_head) residente in RAM (float32).
* Expert letti dal disco on-demand via pread+fadvise(DONTNEED), cache LRU per-layer.
* Matmul multi-thread con OpenMP (niente BLAS).
*
* ENV VARS:
* PILOT=0/1/2 : 0=no prefetch, 1=1-layer lookahead, 2=2-layer lookahead [IMPROVEMENT 1]
* HOT=N : pin top-N hot experts per layer permanently (never evict) [IMPROVEMENT 2]
* WARMUP=N : tokens before hot pinning activates (default 5) [IMPROVEMENT 2]
* REBAL=N : rebalance cache per-layer every N tokens (0=off) [IMPROVEMENT 3]
* WIDE=N : prefetch top-K*N candidates (default 1, try 2 or 3) [IMPROVEMENT 4]
* (expert queue is sorted by eid for SSD locality) [IMPROVEMENT 5]
*/
#define _GNU_SOURCE
#include <stdio.h>
@@ -12,11 +20,22 @@
#include <string.h>
#include <math.h>
#include <time.h>
#include <pthread.h>
#if defined(__APPLE__) || defined(__linux__) || defined(__FreeBSD__)
#include <sys/resource.h>
#include <unistd.h>
#endif
#include "st.h"
#ifdef _WIN32
#include <windows.h>
#define sleep_ms(ms) Sleep(ms)
#else
#define sleep_ms(ms) usleep((ms) * 1000)
#endif
/* ---------- config ---------- */
typedef struct {
int hidden, n_layers, n_heads, n_kv_heads, head_dim;
@@ -33,22 +52,44 @@ typedef struct {
* Ogni weight [out,in] tenuto come int8 (per-riga) + scala float per riga.
* Cosi' la RAM-cache scende da 4 byte/param (f32) a 1 byte/param: e' il
* meccanismo che fa stare GLM-5.2 nei 15 GB. dequant-on-use nel matmul. */
typedef struct { int eid; int8_t *g, *u, *d; float *gs, *us, *ds; uint64_t used; } Slot;
typedef struct { Slot *slots; int n, cap; } LCache;
/* IMPROVEMENT 2: pinned=1 means this slot is never evicted (hot expert). */
typedef struct { int eid; int pinned; int8_t *g, *u, *d; float *gs, *us, *ds; uint64_t used; } Slot;
/* IMPROVEMENT 3: per-layer hit/miss stats for adaptive rebalancing. */
typedef struct { Slot *slots; int n, cap; uint64_t layer_hits, layer_miss; } LCache;
typedef struct {
Cfg c;
shards S;
int quant_bits; /* bit di quantizzazione degli expert (2..8); storage int8, niente f32 (#134) */
int quant_bits;
float *embed, *lm_head, *final_norm;
Layer *L;
LCache *cache; /* [n_layers] */
uint64_t clock, hits, miss;
/* kv-cache per-layer: K,V come [H * maxT * head_dim] */
float **K, **V; int kv_len, max_t;
double dense_load_s;
/* IMPROVEMENT 2: expert frequency heatmap */
uint32_t *freq;
int freq_token_count, hot_pinned, hot_n, warmup_tokens;
/* IMPROVEMENT 3: adaptive rebalance */
int token_count, rebal_interval, total_cap;
/* PREDICTION IMPROVEMENT A: per-layer smoothed gate logits across tokens.
* momentum_logits[l*E .. (l+1)*E-1] = EMA of recent gate outputs.
* Blended with fresh gate prediction: final = (1-smooth)*fresh + smooth*ema.
* Captures routing consistency across tokens (same token tends to reuse experts). */
float *momentum_logits; /* [n_layers * n_experts], EMA of gate logits */
float pilot_smooth; /* SMOOTH env: EMA coefficient 0.0-0.9 (default 0.3) */
uint8_t *is_pinned; /* [n_layers * n_experts], 1 if expert is globally pinned */
} Model;
static pthread_mutex_t g_pilot_mx = PTHREAD_MUTEX_INITIALIZER;
static struct { int l, e; } pilot_q[4096];
static volatile unsigned pilot_r = 0, pilot_w = 0;
static Model *pilot_m = NULL;
static int g_pilot = 0;
static int g_wide = 1; /* IMPROVEMENT 4: top-K * g_wide candidates prefetched */
static void pilot_prefetch(Model *m, int lnext, const float *x, int S);
/* ---------- utility ---------- */
static double now_s(void) { struct timespec t; clock_gettime(CLOCK_MONOTONIC, &t); return t.tv_sec + t.tv_nsec*1e-9; }
#if defined(__APPLE__)
@@ -209,8 +250,24 @@ static void model_init(Model *m, const char *snap, int cap, int bits) {
LD(gate, "mlp.gate.weight");
#undef LD
}
m->total_cap = cap;
m->cache = calloc(c->n_layers, sizeof(LCache));
for (int i = 0; i < c->n_layers; i++) { m->cache[i].cap = cap; m->cache[i].slots = calloc(cap, sizeof(Slot)); }
/* IMPROVEMENT 2: frequency heatmap for hot expert pinning */
m->freq = calloc((size_t)c->n_layers * c->n_experts, sizeof(uint32_t));
m->hot_pinned = 0; m->freq_token_count = 0;
m->hot_n = getenv("HOT") ? atoi(getenv("HOT")) : 0;
m->warmup_tokens = getenv("WARMUP") ? atoi(getenv("WARMUP")) : 5;
/* IMPROVEMENT 3: adaptive rebalance */
m->rebal_interval = getenv("REBAL") ? atoi(getenv("REBAL")) : 0;
m->token_count = 0;
/* PREDICTION A: routing momentum — EMA of gate logits across tokens.
* Initialized to zero; first token sets EMA = fresh logits. */
m->momentum_logits = calloc((size_t)c->n_layers * c->n_experts, sizeof(float));
float sv = getenv("SMOOTH") ? (float)atof(getenv("SMOOTH")) : 0.3f;
if (sv < 0.f) sv = 0.f; if (sv > 0.95f) sv = 0.95f;
m->pilot_smooth = sv;
m->is_pinned = calloc((size_t)c->n_layers * c->n_experts, sizeof(uint8_t));
m->dense_load_s = now_s() - t0;
}
@@ -233,10 +290,13 @@ static void load_expert_w(Model *m, const char *name, int8_t *q, float *scale, i
/* ---------- cache expert: ritorna i pesi quantizzati (q+scale) da cache o disco ---------- */
static void expert_get(Model *m, int layer, int eid, Slot **out) {
LCache *lc = &m->cache[layer];
pthread_mutex_lock(&g_pilot_mx);
for (int i = 0; i < lc->n; i++) if (lc->slots[i].eid == eid) {
m->hits++; lc->slots[i].used = ++m->clock; *out = &lc->slots[i]; return;
m->hits++; lc->layer_hits++; lc->slots[i].used = ++m->clock; *out = &lc->slots[i];
pthread_mutex_unlock(&g_pilot_mx);
return;
}
m->miss++;
m->miss++; lc->layer_miss++;
Cfg *c = &m->c;
int64_t ng = (int64_t)c->inter * c->hidden, nd = (int64_t)c->hidden * c->inter;
Slot *s;
@@ -244,15 +304,107 @@ static void expert_get(Model *m, int layer, int eid, Slot **out) {
s = &lc->slots[lc->n++];
s->g = malloc(ng); s->u = malloc(ng); s->d = malloc(nd);
s->gs = falloc(c->inter); s->us = falloc(c->inter); s->ds = falloc(c->hidden);
} else { int lru = 0; for (int i = 1; i < lc->n; i++) if (lc->slots[i].used < lc->slots[lru].used) lru = i; s = &lc->slots[lru]; }
s->pinned = 0;
} else {
/* IMPROVEMENT 2: LRU eviction — never evict pinned experts */
int lru = -1;
for (int i = 0; i < lc->n; i++) {
if (lc->slots[i].pinned) continue;
if (lru < 0 || lc->slots[i].used < lc->slots[lru].used) lru = i;
}
if (lru < 0) lru = 0; /* all pinned: fallback evict oldest */
s = &lc->slots[lru];
s->pinned = 0;
}
s->eid = -1;
s->used = ++m->clock;
pthread_mutex_unlock(&g_pilot_mx);
float *tmp = falloc(ng > nd ? ng : nd);
char nm[256];
snprintf(nm,sizeof(nm),"model.layers.%d.mlp.experts.%d.gate_proj.weight",layer,eid); load_expert_w(m,nm,s->g,s->gs,c->inter,c->hidden,tmp);
snprintf(nm,sizeof(nm),"model.layers.%d.mlp.experts.%d.up_proj.weight", layer,eid); load_expert_w(m,nm,s->u,s->us,c->inter,c->hidden,tmp);
snprintf(nm,sizeof(nm),"model.layers.%d.mlp.experts.%d.down_proj.weight",layer,eid); load_expert_w(m,nm,s->d,s->ds,c->hidden,c->inter,tmp);
free(tmp);
s->eid = eid; s->used = ++m->clock;
pthread_mutex_lock(&g_pilot_mx);
s->eid = eid;
s->pinned = m->is_pinned[layer * c->n_experts + eid];
s->used = ++m->clock;
*out = s;
pthread_mutex_unlock(&g_pilot_mx);
}
/* ---------- IMPROVEMENT 2: pin top-N hot experts per layer ---------- */
static void pin_hot_experts(Model *m) {
Cfg *c = &m->c;
if (m->hot_n <= 0 || m->hot_pinned) return;
m->hot_pinned = 1;
int hn = m->hot_n < c->n_experts ? m->hot_n : c->n_experts;
int pinned_total = 0;
for (int l = 0; l < c->n_layers; l++) {
uint32_t *freq_l = m->freq + (int64_t)l * c->n_experts;
int hot_eids[256];
/* Find top hn experts by activation frequency */
for (int k = 0; k < hn; k++) {
int best = -1; uint32_t bv = 0;
for (int e = 0; e < c->n_experts; e++) {
int already = 0;
for (int j = 0; j < k; j++) if (hot_eids[j] == e) { already=1; break; }
if (!already && freq_l[e] > bv) { bv = freq_l[e]; best = e; }
}
if (best < 0 || bv == 0) { hn = k; break; }
hot_eids[k] = best;
}
/* Mark already-cached hot experts as pinned; enqueue uncached ones */
for (int k = 0; k < hn; k++) {
int eid = hot_eids[k];
m->is_pinned[l * c->n_experts + eid] = 1; // Mark globally
LCache *lc = &m->cache[l];
int found = 0;
pthread_mutex_lock(&g_pilot_mx);
for (int i = 0; i < lc->n; i++) {
if (lc->slots[i].eid == eid) { lc->slots[i].pinned = 1; found = 1; break; }
}
pthread_mutex_unlock(&g_pilot_mx);
if (!found) {
unsigned w = __atomic_load_n(&pilot_w, __ATOMIC_RELAXED);
unsigned r = __atomic_load_n(&pilot_r, __ATOMIC_ACQUIRE);
if (w - r < 4096) {
pilot_q[w & 4095].l = l; pilot_q[w & 4095].e = eid;
__atomic_store_n(&pilot_w, w + 1, __ATOMIC_RELEASE);
}
}
pinned_total++;
}
}
printf("[HOT] Pinned %d experts (top-%d/layer) after %d warmup tokens\n",
pinned_total, m->hot_n, m->freq_token_count);
}
/* ---------- IMPROVEMENT 3: adaptive per-layer cache rebalancing ---------- */
static void rebalance_cache(Model *m) {
Cfg *c = &m->c;
uint64_t total_miss = 0;
for (int l = 0; l < c->n_layers; l++) total_miss += m->cache[l].layer_miss;
if (total_miss == 0) return;
int min_cap = 4;
int budget = m->total_cap - min_cap * c->n_layers;
if (budget < 0) budget = 0;
for (int l = 0; l < c->n_layers; l++) {
double frac = (double)m->cache[l].layer_miss / (double)total_miss;
int new_cap = min_cap + (int)(frac * budget + 0.5);
LCache *lc = &m->cache[l];
if (new_cap > lc->cap) {
Slot *ns = realloc(lc->slots, new_cap * sizeof(Slot));
if (ns) {
memset(ns + lc->cap, 0, (new_cap - lc->cap) * sizeof(Slot));
lc->slots = ns; lc->cap = new_cap;
}
}
lc->layer_hits = 0; lc->layer_miss = 0;
}
}
/* ---------- RoPE su un vettore di una testa (head_dim) a posizione assoluta pos ---------- */
@@ -337,6 +489,11 @@ static void moe(Model *m, Layer *l, int layer, float *x, int S, float *out) {
idx[kk] = best; val[kk] = bv;
}
if (c->norm_topk) { float sm=0; for(int kk=0;kk<K;kk++) sm+=val[kk]; for(int kk=0;kk<K;kk++) val[kk]/=sm; }
/* IMPROVEMENT 2: update activation heatmap (before pinning activates) */
if (!m->hot_pinned && m->freq) {
uint32_t *freq_l = m->freq + (int64_t)layer * E;
for (int kk = 0; kk < K; kk++) if (idx[kk] >= 0) freq_l[idx[kk]]++;
}
const float *xs = x + (int64_t)s*D;
for (int kk = 0; kk < K; kk++) {
Slot *e; expert_get(m, layer, idx[kk], &e);
@@ -363,12 +520,26 @@ static float *step(Model *m, const int *ids, int S, int pos_base) {
for (int s = 0; s < S; s++) rmsnorm_row(nrm + (int64_t)s*D, x + (int64_t)s*D, l->in_ln, D, c->eps);
attention(m, l, i, nrm, S, pos_base, tmp);
for (int64_t j = 0; j < (int64_t)S*D; j++) x[j] += tmp[j];
/* IMPROVEMENT 1: PILOT=1 -> 1-layer lookahead */
if (g_pilot >= 1 && S <= 8 && i + 1 < c->n_layers)
pilot_prefetch(m, i + 1, x, S);
for (int s = 0; s < S; s++) rmsnorm_row(nrm + (int64_t)s*D, x + (int64_t)s*D, l->post_ln, D, c->eps);
moe(m, l, i, nrm, S, tmp);
for (int64_t j = 0; j < (int64_t)S*D; j++) x[j] += tmp[j];
/* PREDICTION IMPROVEMENT C (Residual gate trick):
* PILOT=2 -> prefetch layer i+2 using completed state x (containing MoE residual). */
if (g_pilot >= 2 && S <= 8 && i + 2 < c->n_layers)
pilot_prefetch(m, i + 2, x, S);
}
/* IMPROVEMENT 2: count tokens; trigger hot pinning after warmup */
m->token_count++; m->freq_token_count++;
if (!m->hot_pinned && m->hot_n > 0 && m->freq_token_count >= m->warmup_tokens)
pin_hot_experts(m);
/* IMPROVEMENT 3: periodic adaptive rebalance */
if (m->rebal_interval > 0 && m->token_count % m->rebal_interval == 0)
rebalance_cache(m);
m->kv_len = pos_base + S;
/* solo l'ultimo token -> logits */
float *last = falloc(D);
rmsnorm_row(last, x + (int64_t)(S-1)*D, m->final_norm, D, c->eps);
float *logit = falloc(c->vocab);
@@ -377,6 +548,155 @@ static float *step(Model *m, const int *ids, int S, int pos_base) {
return logit;
}
static void pilot_realload(Model *m, int layer, int eid) {
LCache *lc = &m->cache[layer];
Cfg *c = &m->c;
int64_t ng = (int64_t)c->inter * c->hidden, nd = (int64_t)c->hidden * c->inter;
pthread_mutex_lock(&g_pilot_mx);
for (int i = 0; i < lc->n; i++) {
if (lc->slots[i].eid == eid) { pthread_mutex_unlock(&g_pilot_mx); return; }
}
Slot *s;
if (lc->n < lc->cap) {
s = &lc->slots[lc->n++];
s->g = malloc(ng); s->u = malloc(ng); s->d = malloc(nd);
s->gs = falloc(c->inter); s->us = falloc(c->inter); s->ds = falloc(c->hidden);
s->pinned = 0;
} else {
/* IMPROVEMENT 2: never evict pinned experts */
int lru = -1;
for (int i = 0; i < lc->n; i++) {
if (lc->slots[i].pinned) continue;
if (lru < 0 || lc->slots[i].used < lc->slots[lru].used) lru = i;
}
if (lru < 0) { pthread_mutex_unlock(&g_pilot_mx); return; } /* all pinned, skip */
s = &lc->slots[lru]; s->pinned = 0;
}
s->eid = -1; s->used = ++m->clock;
pthread_mutex_unlock(&g_pilot_mx);
float *tmp = falloc(ng > nd ? ng : nd);
char nm[256];
snprintf(nm, sizeof(nm), "model.layers.%d.mlp.experts.%d.gate_proj.weight", layer, eid);
load_expert_w(m, nm, s->g, s->gs, c->inter, c->hidden, tmp);
snprintf(nm, sizeof(nm), "model.layers.%d.mlp.experts.%d.up_proj.weight", layer, eid);
load_expert_w(m, nm, s->u, s->us, c->inter, c->hidden, tmp);
snprintf(nm, sizeof(nm), "model.layers.%d.mlp.experts.%d.down_proj.weight", layer, eid);
load_expert_w(m, nm, s->d, s->ds, c->hidden, c->inter, tmp);
free(tmp);
pthread_mutex_lock(&g_pilot_mx);
s->eid = eid;
s->pinned = m->is_pinned[layer * c->n_experts + eid];
s->used = ++m->clock;
pthread_mutex_unlock(&g_pilot_mx);
}
static void *pilot_worker(void *arg) {
(void)arg;
while (1) {
unsigned r = __atomic_load_n(&pilot_r, __ATOMIC_ACQUIRE);
unsigned w = __atomic_load_n(&pilot_w, __ATOMIC_ACQUIRE);
if (r == w) {
sleep_ms(1);
continue;
}
int layer = pilot_q[r & 4095].l;
int eid = pilot_q[r & 4095].e;
pilot_realload(pilot_m, layer, eid);
__atomic_store_n(&pilot_r, r + 1, __ATOMIC_RELEASE);
}
return NULL;
}
static void pilot_prefetch(Model *m, int lnext, const float *x, int S) {
if (lnext < 0 || lnext >= m->c.n_layers) return;
Cfg *c = &m->c; int D = c->hidden, E = c->n_experts;
/* IMPROVEMENT 4: wide prefetch — top K * g_wide candidates */
int cand = c->topk * g_wide;
if (cand > E) cand = E;
if (!pilot_m) {
pilot_m = m;
pthread_t t;
pthread_create(&t, NULL, pilot_worker, NULL);
}
float *logits = falloc((int64_t)S * E);
Layer *l = &m->L[lnext];
// PREDICTION IMPROVEMENT B: Apply RMSNorm to x using destination layer's post_ln
// This scales inputs to the distribution expected by l->gate.
float *nrm_x = falloc((int64_t)S * D);
for (int s = 0; s < S; s++) {
rmsnorm_row(nrm_x + (int64_t)s * D, x + (int64_t)s * D, l->post_ln, D, c->eps);
}
matmul(logits, nrm_x, l->gate, S, D, E);
free(nrm_x);
for (int s = 0; s < S; s++) {
float *pr = logits + (int64_t)s * E;
// PREDICTION IMPROVEMENT A: Apply routing momentum (EMA of gate logits)
float *blended = pr;
float *ema = m->momentum_logits + (int64_t)lnext * E;
if (m->pilot_smooth > 0.f) {
blended = falloc(E);
int is_zero = 1;
for (int e = 0; e < E; e++) { if (ema[e] != 0.f) { is_zero = 0; break; } }
if (is_zero) {
for (int e = 0; e < E; e++) {
ema[e] = pr[e];
blended[e] = pr[e];
}
} else {
for (int e = 0; e < E; e++) {
blended[e] = (1.f - m->pilot_smooth) * pr[e] + m->pilot_smooth * ema[e];
ema[e] = blended[e]; // update EMA
}
}
}
int idx[128]; /* up to topk * 4 */
for (int kk = 0; kk < cand; kk++) {
int best = -1; float bv = -1e30f;
for (int e = 0; e < E; e++) {
int taken = 0; for (int j = 0; j < kk; j++) if (idx[j] == e) { taken=1; break; }
if (!taken && blended[e] > bv) { bv = blended[e]; best = e; }
}
idx[kk] = best;
}
if (blended != pr) free(blended);
/* IMPROVEMENT 5: sort candidates by eid for sequential SSD read locality */
for (int a = 0; a < cand-1; a++)
for (int b = a+1; b < cand; b++)
if (idx[b] >= 0 && (idx[a] < 0 || idx[a] > idx[b])) { int t = idx[a]; idx[a] = idx[b]; idx[b] = t; }
for (int kk = 0; kk < cand; kk++) {
int eid = idx[kk];
if (eid < 0) continue;
int found = 0;
pthread_mutex_lock(&g_pilot_mx);
LCache *lc = &m->cache[lnext];
for (int z = 0; z < lc->n; z++) {
if (lc->slots[z].eid == eid) { found = 1; break; }
}
pthread_mutex_unlock(&g_pilot_mx);
if (!found) {
unsigned w2 = __atomic_load_n(&pilot_w, __ATOMIC_RELAXED);
unsigned r2 = __atomic_load_n(&pilot_r, __ATOMIC_ACQUIRE);
if (w2 - r2 < 4096) {
pilot_q[w2 & 4095].l = lnext;
pilot_q[w2 & 4095].e = eid;
__atomic_store_n(&pilot_w, w2 + 1, __ATOMIC_RELEASE);
}
}
}
}
free(logits);
}
/* generazione greedy. prompt[np] -> riempie out[np+n_new] */
static void generate(Model *m, const int *prompt, int np, int n_new, int *out) {
Cfg *c = &m->c;
@@ -411,22 +731,30 @@ static int *read_int_array(jval *o, const char *key, int *n_out) {
int main(int argc, char **argv) {
const char *snap = getenv("SNAP");
if (!snap) { fprintf(stderr, "set SNAP=<snapshot directory>\n"); return 1; }
int cap = argc > 1 ? atoi(argv[1]) : 16;
int bits = argc > 2 ? atoi(argv[2]) : 8;
if (bits < 2 || bits > 8) { /* expert storage is int8_t: bits>8 truncates in quantize_rows (#134). f32 mode is not implemented here — int8 is already token-exact vs the oracle. */
fprintf(stderr, "quant_bits must be 2..8 (got %d); OLMoE experts are int8-backed, no f32 mode\n", bits);
g_pilot = getenv("PILOT") ? atoi(getenv("PILOT")) : 0;
g_wide = getenv("WIDE") ? atoi(getenv("WIDE")) : 1;
if (g_wide < 1) g_wide = 1;
if (g_wide > 4) g_wide = 4;
int hot_n = getenv("HOT") ? atoi(getenv("HOT")) : 0;
int rebal = getenv("REBAL") ? atoi(getenv("REBAL")) : 0;
int cap = argc > 1 ? atoi(argv[1]) : 16;
int bits = argc > 2 ? atoi(argv[2]) : 8;
if (bits < 2 || bits > 8) {
fprintf(stderr, "quant_bits must be 2..8 (got %d)\n", bits);
return 1;
}
const char *refpath = argc > 3 ? argv[3] : "ref.json";
FILE *f = fopen(refpath, "rb"); if(!f){perror(refpath);return 1;}
printf("== Streaming C engine v2 | cache=%d/layer bits=%d pilot=%d wide=%d hot=%d rebal=%d ==\n",
cap, bits, g_pilot, g_wide, hot_n, rebal);
FILE *f = fopen(refpath, "rb"); if (!f) { perror(refpath); return 1; }
fseek(f,0,SEEK_END); long n=ftell(f); fseek(f,0,SEEK_SET);
char *buf=malloc(n+1); if(fread(buf,1,n,f)!=(size_t)n){} buf[n]=0; fclose(f);
char *buf=malloc(n+1); if (fread(buf,1,n,f)!=(size_t)n) {} buf[n]=0; fclose(f);
char *arena=NULL; jval *ref = json_parse(buf, &arena);
int np, nfull; int *prompt = read_int_array(ref,"prompt_ids",&np); int *full = read_int_array(ref,"full_ids",&nfull);
int n_new = nfull - np;
printf("== Streaming C engine, cache = %d experts/layer, experts @ %d-bit ==\n", cap, bits);
Model m; model_init(&m, snap, cap, bits);
printf("resident weights loaded in %.1fs | RSS after load: %.2f GB\n", m.dense_load_s, rss_gb());