memra-engine 0.137.0

From-scratch CUDA LLM inference engine for NVIDIA RTX 50-series (sm_120a) and Hopper (sm_90a) - custom kernels, no frameworks
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
//! Isolated full-replay dense-tail experiment; no shared replay/runtime edits.
//! Both arms retain full replay/device sampler/diet, differing only in captured
//! dense M=1 kernel functions. First capture is timed once for EACH scored arm.
use memra_engine::dsv4_gpu::{DecodeState, Dsv4Gpu, Dsv4SampleCfg, dsv4_pos_uniform, dsv4_prof_on};
use memra_engine::dsv4_sampler::{Dsv4DeviceSampler, Dsv4Sampler, dsv4_sampler};
use memra_gguf::dsv4_forward::ActQuantVariant;
use memra_tokenizer::Tokenizer;
use sha2::{Digest, Sha256};
use std::{
    ffi::c_int,
    path::{Path, PathBuf},
    time::Instant,
};

const PRIME: usize = 256;
const OUTPUT: usize = 256;
const CAPACITY: usize = PRIME + OUTPUT + 8;
const SOURCE_SHA: &str = "f6e175a6f2588953568746fec0cd43fcd046405f74b5c71ce071fe7f37238ded";
const FP8_NODES: &str = "dsv4_dense_exact_tail_fp8_kernel";
const DOT_NODES: &str = "dsv4_dense_exact_tail_dots_kernel";
const CONTROL_FP8: &str = "dsv4_gemv_fp8_m_kernel";
const CONTROL_DOTS: &str = "dsv4_dots_f32acc_mrow_kernel";

// Existing gate-only C ABI. Selection runs only on this host thread before
// capture; captured functions never read it. No runtime/serving interface added.
unsafe extern "C" {
    fn memra_dsv4_dense_exact_tail_set_for_gate(enabled: c_int) -> c_int;
    fn memra_dsv4_dense_exact_tail_counts_for_gate(fp8: *mut u64, dots: *mut u64) -> c_int;
}
fn enqueues() -> [u64; 2] {
    let mut c = [0u64; 2];
    let rc = unsafe { memra_dsv4_dense_exact_tail_counts_for_gate(&mut c[0], &mut c[1]) };
    assert_eq!(rc, 0, "dense enqueue read");
    c
}
fn drain(gpu: &Dsv4Gpu) {
    for stage in &gpu.stages {
        stage.gpu.stream().synchronize().expect("both-rank drain");
    }
}
fn select(gpu: &Dsv4Gpu, on: bool) {
    drain(gpu);
    assert_eq!(
        unsafe { memra_dsv4_dense_exact_tail_set_for_gate(i32::from(on)) },
        0
    );
}
fn sha_f32(row: &[f32]) -> String {
    assert!(row.iter().all(|v| v.is_finite()), "finite final logits");
    let mut h = Sha256::new();
    for v in row {
        h.update(v.to_bits().to_le_bytes());
    }
    format!("{:x}", h.finalize())
}
fn sha_tokens(tokens: &[u32]) -> String {
    let mut h = Sha256::new();
    for v in tokens {
        h.update(v.to_le_bytes());
    }
    format!("{:x}", h.finalize())
}
fn looped(tokens: &[u32]) -> bool {
    (1usize..=32).any(|width| {
        let length = width * 4usize.max(32usize.div_ceil(width));
        tokens
            .windows(length)
            .any(|span| span.chunks_exact(width).all(|c| c == &span[..width]))
    })
}
type Identity = (String, [u64; 2], [u64; 2]);
fn identity(gpu: &Dsv4Gpu, state: &DecodeState) -> Identity {
    let logits = gpu
        .read_decode_logits_for_gate(state)
        .expect("final logits");
    let cache = gpu
        .tp_ep_cache_digest_for_gate(state)
        .expect("cache digest");
    let hidden = gpu
        .tp_ep_hidden_digest_for_gate(state)
        .expect("hidden digest");
    assert_eq!(cache[0], cache[1], "cache rank symmetry");
    assert_eq!(hidden[0], hidden[1], "hidden rank symmetry");
    (sha_f32(&logits), cache, hidden)
}
fn state(gpu: &Dsv4Gpu) -> DecodeState {
    gpu.alloc_decode_state_for_transient(CAPACITY, 1)
        .expect("independent state")
}
fn epochs(gpu: &Dsv4Gpu, before: &[Vec<u32>; 2], steps: u32) {
    let after = gpu
        .full_token_ar_epochs_for_gate()
        .expect("device AR epochs");
    let attention = memra_engine::tp_ar::ar_blocks_for(4096) as usize;
    let expert = memra_engine::tp_ar::ar_blocks_for(6 * 4096) as usize;
    for rank in 0..2 {
        assert_eq!(before[rank].len(), 72);
        assert_eq!(after[rank].len(), 72);
        for block in 0..72 {
            let per_step = 43 * (u32::from(block < attention) + u32::from(block < expert));
            assert_eq!(
                after[rank][block].wrapping_sub(before[rank][block]),
                per_step * steps,
                "AR epoch rank {rank} block {block}"
            );
        }
    }
}
fn captures_once(gpu: &Dsv4Gpu, state: &DecodeState) {
    assert_eq!(
        gpu.full_token_replay_captures_for_gate(state).unwrap(),
        [1, 1]
    );
    for rank in gpu.full_token_replay_census_for_gate(state).unwrap() {
        assert_eq!(rank[0][2], 86, "43 layers, two ARs each");
        assert_eq!(rank[0][3], 1, "embedding");
        assert_eq!(rank[0][4], 86, "HC posts");
        assert_eq!(rank[0][6], 0, "unsupported forward nodes");
        assert_eq!(rank[1][6], 0, "unsupported commit nodes");
    }
}
fn replay_delta(
    gpu: &Dsv4Gpu,
    state: &DecodeState,
    before: [[u64; 2]; 2],
    steps: u64,
) -> [[u64; 2]; 2] {
    let after = gpu.full_token_replay_counts_for_gate(state).unwrap();
    for r in 0..2 {
        for segment in 0..2 {
            assert_eq!(after[r][segment] - before[r][segment], steps);
        }
    }
    after
}
fn count_kernel(dot: &str, needle: &str) -> usize {
    // CUDA verbose DOT has one ID record per kernel, with symbol and geometry.
    // Counting this record avoids graph labels/edges or repeated pointer text.
    dot.lines()
        .filter(|line| line.trim_start().starts_with("| {ID |") && line.contains(needle))
        .count()
}
fn dense_census(gpu: &Dsv4Gpu, state: &DecodeState, on: bool, dir: &Path) -> [[String; 2]; 2] {
    captures_once(gpu, state);
    std::fs::create_dir_all(dir).expect("graph directory");
    gpu.dump_full_token_replay_for_gate(state, dir)
        .expect("public graph dump");
    let mut hashes: [[String; 2]; 2] = Default::default();
    for (rank, row) in hashes.iter_mut().enumerate() {
        for (segment, hash) in row.iter_mut().enumerate() {
            let path = dir.join(format!("full-token-rank{rank}-segment{segment}.dot"));
            let dot = std::fs::read_to_string(path).expect("DOT");
            let expected = if segment == 0 {
                [494, 253]
            } else if rank == 1 {
                [0, 2]
            } else {
                [0, 0]
            };
            let candidate = [count_kernel(&dot, FP8_NODES), count_kernel(&dot, DOT_NODES)];
            let control = [
                count_kernel(&dot, CONTROL_FP8),
                count_kernel(&dot, CONTROL_DOTS),
            ];
            assert_eq!(
                candidate,
                if on { expected } else { [0, 0] },
                "candidate rank={rank} segment={segment}"
            );
            assert_eq!(
                control,
                if on { [0, 0] } else { expected },
                "control rank={rank} segment={segment}"
            );
            *hash = format!("{:x}", Sha256::digest(dot.as_bytes()));
            println!(
                "DENSE_CENSUS on={on} rank={rank} segment={segment} candidate={candidate:?} control={control:?} dot_sha256={hash}"
            );
        }
    }
    hashes
}
struct Arm {
    state: DecodeState,
    on: bool,
    graph_hashes: Option<[[String; 2]; 2]>,
}
impl Arm {
    fn new(gpu: &Dsv4Gpu, prefix: &DecodeState, cfg: Dsv4SampleCfg, on: bool) -> Self {
        let mut state = state(gpu);
        gpu.restore_full_token_prefix_for_gate(&mut state, prefix)
            .expect("initial restore");
        // gpu is boxed at a stable address and outlives every Arm; its weights,
        // numeric controls and runtime configuration stay fixed throughout.
        unsafe { gpu.arm_full_token_replay_mode_for_gate(&mut state, cfg, false) }
            .expect("arm full replay");
        assert_eq!(
            gpu.full_token_replay_captures_for_gate(&state).unwrap(),
            [0, 0]
        );
        Self {
            state,
            on,
            graph_hashes: None,
        }
    }
    fn prepare(&self, gpu: &Dsv4Gpu) -> bool {
        let captures = gpu
            .full_token_replay_captures_for_gate(&self.state)
            .unwrap();
        let first = captures == [0, 0];
        if first {
            select(gpu, self.on);
        } else {
            assert_eq!(captures, [1, 1]);
        }
        first
    }
    fn check_enqueues(&self, before: [u64; 2], first: bool) {
        let after = enqueues();
        let expected = if first && self.on { [988, 508] } else { [0, 0] };
        assert_eq!(
            [after[0] - before[0], after[1] - before[1]],
            expected,
            "host enqueues describe capture, never graph replay"
        );
    }
    fn census(&mut self, gpu: &Dsv4Gpu, dir: &Path) {
        let hashes = dense_census(gpu, &self.state, self.on, dir);
        if let Some(prior) = &self.graph_hashes {
            assert_eq!(prior, &hashes, "stable retained graphs after reset");
        } else {
            self.graph_hashes = Some(hashes);
        }
    }
}
fn eager_step(
    gpu: &Dsv4Gpu,
    s: &mut DecodeState,
    sampler: &mut Dsv4DeviceSampler,
    cfg: &Dsv4SampleCfg,
    token: u32,
) -> u32 {
    select(gpu, false);
    let before = enqueues();
    gpu.decode_step_device_logits(token, s)
        .expect("eager control forward");
    let next = gpu
        .sample_device_logits(s, sampler, cfg, &[], None)
        .expect("eager control sample");
    assert_eq!(before, enqueues());
    next
}
fn refusal_cells(
    gpu: &Dsv4Gpu,
    prefix: &DecodeState,
    cfg: Dsv4SampleCfg,
    inputs: &[u32],
    on: bool,
    output: &Path,
) {
    for rank in 0..2 {
        for (position, layer) in [(259usize, 0usize), (383, 21), (511, 42)] {
            let mut failed = Arm::new(gpu, prefix, cfg, on);
            let first = failed.prepare(gpu);
            let before_host = enqueues();
            for &token in &inputs[..position - PRIME] {
                gpu.decode_sample_full_token_for_gate(token, &mut failed.state)
                    .expect("fault setup");
            }
            failed.check_enqueues(before_host, first);
            failed.census(
                gpu,
                &output.join(format!("fault-{}-{rank}-{position}", usize::from(on))),
            );
            let cache = gpu.tp_ep_cache_digest_for_gate(&failed.state).unwrap();
            let counts = gpu
                .full_token_replay_counts_for_gate(&failed.state)
                .unwrap();
            let host = enqueues();
            let code = 40043 + rank as i32;
            gpu.arm_attention_tp_join_refusal_for_gate(layer, rank, code)
                .unwrap();
            let error = gpu
                .decode_sample_full_token_for_gate(inputs[position - PRIME], &mut failed.state)
                .unwrap_err();
            assert!(error.contains("one-shot reduction refused"), "{error}");
            let mut words = [0, 0];
            words[rank] = code;
            assert_eq!(gpu.tp_ep_ar_refusal_words().unwrap(), words);
            assert_eq!(failed.state.pos, position);
            assert_eq!(
                gpu.tp_ep_cache_digest_for_gate(&failed.state).unwrap(),
                cache
            );
            let after = gpu
                .full_token_replay_counts_for_gate(&failed.state)
                .unwrap();
            for r in 0..2 {
                assert_eq!(after[r], [counts[r][0] + 1, counts[r][1]], "refusal commit");
            }
            assert!(
                gpu.decode_sample_full_token_for_gate(inputs[position - PRIME], &mut failed.state)
                    .unwrap_err()
                    .contains("unfinished transaction")
            );
            assert!(
                gpu.restore_full_token_prefix_for_gate(&mut failed.state, prefix)
                    .is_err(),
                "reset bypassed quarantine"
            );
            assert_eq!(
                gpu.full_token_replay_counts_for_gate(&failed.state)
                    .unwrap(),
                after
            );
            assert_eq!(host, enqueues());
            captures_once(gpu, &failed.state);
            println!(
                "REFUSAL on={on} rank={rank} layer={layer} position={position} cache_unchanged=true position_unchanged=true no_commit=true retry_quarantined=true"
            );
            gpu.set_tp_ep_ar_refusal_words_for_gate([0, 0]).unwrap();
        }
    }
}
fn run(gpu: &Dsv4Gpu, prompt: &[u32], tokenizer: &Tokenizer, output: &Path, reverse: bool) {
    let cfg = Dsv4SampleCfg {
        temperature: 1.0,
        top_p: 1.0,
        top_k: 0,
        seed: 20260907,
    };
    select(gpu, false);
    let mut prefix = state(gpu);
    gpu.prefill_with_cache_chunked(&prompt[..1], &mut prefix, 1)
        .expect("prime first");
    for &token in &prompt[1..PRIME] {
        gpu.decode_step_device_logits(token, &mut prefix)
            .expect("prime");
    }
    let mut sampler = gpu.device_sampler().unwrap();
    let first = gpu
        .sample_device_logits(&prefix, &mut sampler, &cfg, &[], None)
        .expect("initial carry draw");
    assert_eq!(prefix.pos, PRIME);
    assert_eq!(gpu.tp_ep_ar_refusal_words().unwrap(), [0, 0]);
    let prefix_identity = identity(gpu, &prefix);
    let mut eager = state(gpu);
    gpu.restore_full_token_prefix_for_gate(&mut eager, &prefix)
        .unwrap();
    let mut control = Arm::new(gpu, &prefix, cfg, false);
    let mut candidate = Arm::new(gpu, &prefix, cfg, true);
    let mut inputs = Vec::with_capacity(OUTPUT);
    let mut carry = first;
    for step in 0..OUTPUT {
        assert_ne!(carry, tokenizer.eos_id(), "correctness early EOS");
        inputs.push(carry);
        let before_epochs = gpu.full_token_ar_epochs_for_gate().unwrap();
        let next = eager_step(gpu, &mut eager, &mut sampler, &cfg, carry);
        for arm in [&mut control, &mut candidate] {
            let capturing = arm.prepare(gpu);
            let host = enqueues();
            let actual = gpu
                .decode_sample_full_token_for_gate(carry, &mut arm.state)
                .expect("correctness full replay");
            assert_eq!(
                actual, next,
                "first/changing sample step={step} on={}",
                arm.on
            );
            arm.check_enqueues(host, capturing);
            assert_eq!(arm.state.pos, PRIME + step + 1);
            assert_eq!(
                identity(gpu, &arm.state),
                identity(gpu, &eager),
                "logits/cache/hidden step={step}"
            );
            assert_eq!(gpu.tp_ep_ar_refusal_words().unwrap(), [0, 0]);
            assert_eq!(
                gpu.full_token_replay_counts_for_gate(&arm.state).unwrap(),
                [[step as u64 + 1; 2]; 2]
            );
            captures_once(gpu, &arm.state);
            if step == 0 {
                arm.census(
                    gpu,
                    &output.join(if arm.on { "qual-on" } else { "qual-off" }),
                );
            }
        }
        epochs(gpu, &before_epochs, 3);
        if step == 0 {
            assert_eq!(
                gpu.full_token_replay_census_for_gate(&control.state)
                    .unwrap(),
                gpu.full_token_replay_census_for_gate(&candidate.state)
                    .unwrap(),
                "candidate changes kernel identity, not graph structure/counts"
            );
        }
        carry = next;
        if step == 0 || (PRIME + step + 1).is_multiple_of(4) {
            println!(
                "EXACT position={} next_token={carry} eager_off_graph_off_graph_on_identical=true",
                PRIME + step + 1
            );
        }
    }
    assert!(!looped(&inputs));
    let expected_tokens = sha_tokens(&inputs);
    let expected_identity = identity(gpu, &eager);
    let expected_next = carry;
    // Restore into the SAME captured allocations, then replay the changing tape
    // once more to prove stable reset independently of the timed rows.
    for arm in [&mut control, &mut candidate] {
        gpu.restore_full_token_prefix_for_gate(&mut arm.state, &prefix)
            .unwrap();
        assert_eq!(identity(gpu, &arm.state), prefix_identity);
        let counts = gpu.full_token_replay_counts_for_gate(&arm.state).unwrap();
        let before_epochs = gpu.full_token_ar_epochs_for_gate().unwrap();
        let host = enqueues();
        let mut token = first;
        for &expected in &inputs {
            assert_eq!(token, expected);
            token = gpu
                .decode_sample_full_token_for_gate(token, &mut arm.state)
                .unwrap();
        }
        assert_eq!(token, expected_next);
        assert_eq!(identity(gpu, &arm.state), expected_identity);
        assert_eq!(enqueues(), host);
        replay_delta(gpu, &arm.state, counts, OUTPUT as u64);
        epochs(gpu, &before_epochs, OUTPUT as u32);
        arm.census(
            gpu,
            &output.join(if arm.on {
                "qual-reset-on"
            } else {
                "qual-reset-off"
            }),
        );
    }
    drop(control);
    drop(candidate);
    drop(eager);
    refusal_cells(gpu, &prefix, cfg, &inputs, false, output);
    refusal_cells(gpu, &prefix, cfg, &inputs, true, output);
    println!(
        "PASS dense model correctness, two retained resets, and 12 live refusal cells; timing begins"
    );

    // BOTH scored arms are new and uncaptured, independent of qualification.
    // First ON row and first OFF row each include their actual graph-capture cost.
    let mut arms = [
        Arm::new(gpu, &prefix, cfg, false),
        Arm::new(gpu, &prefix, cfg, true),
    ];
    let mut walls = [0u128; 2];
    let mut rates = [Vec::new(), Vec::new()];
    let mut first_capture_rows = [0usize; 2];
    let schedule = if reverse {
        "OFF ON ON OFF"
    } else {
        "ON OFF OFF ON"
    };
    println!(
        "PROTOCOL blocks={schedule:?} rows_per_block=5 rows=20 prime=256 output=256 both_full_replay=true device_sampler=true diet=true splitk=false cadence=false gu_n32=false first_capture_each_arm_inside_timing=true initial_carry_outside_timing=true final_next_draw_inside_timing=true timing_scope=sample_plus_forward_envelope control_hash_provenance=host_reconstructed_intended_sequence"
    );
    for row in 0..20 {
        let on = matches!(row / 5, 0 | 3) != reverse;
        let index = usize::from(on);
        let active = &mut arms[index];
        gpu.restore_full_token_prefix_for_gate(&mut active.state, &prefix)
            .expect("stable row restore");
        assert_eq!(identity(gpu, &active.state), prefix_identity);
        let first_capture = active.prepare(gpu);
        let host = enqueues();
        let before_counts = gpu
            .full_token_replay_counts_for_gate(&active.state)
            .unwrap();
        let before_epochs = gpu.full_token_ar_epochs_for_gate().unwrap();
        let mut carry = first;
        let mut tokens = Vec::with_capacity(OUTPUT);
        let start = Instant::now();
        for _ in 0..OUTPUT {
            assert_ne!(carry, tokenizer.eos_id(), "early EOS row");
            tokens.push(carry);
            carry = gpu
                .decode_sample_full_token_for_gate(carry, &mut active.state)
                .expect("scored replay");
        }
        drain(gpu);
        let wall = start.elapsed().as_nanos();
        assert!(!looped(&tokens));
        assert_eq!(sha_tokens(&tokens), expected_tokens);
        assert_eq!(carry, expected_next);
        assert_eq!(active.state.pos, 512);
        assert_eq!(identity(gpu, &active.state), expected_identity);
        assert_eq!(gpu.tp_ep_ar_refusal_words().unwrap(), [0, 0]);
        active.check_enqueues(host, first_capture);
        let counts = replay_delta(gpu, &active.state, before_counts, OUTPUT as u64);
        epochs(gpu, &before_epochs, OUTPUT as u32);
        captures_once(gpu, &active.state);
        // Dump once after first capture and again after the arm's final reset.
        // All rows still assert captures/replays/epochs; no repeated DOT I/O is timed.
        if first_capture || rates[index].len() == 9 {
            active.census(
                gpu,
                &output.join(format!("row-{row:02}-{}", if on { "on" } else { "off" })),
            );
        }
        first_capture_rows[index] += usize::from(first_capture);
        walls[index] += wall;
        let rate = OUTPUT as f64 * 1e9 / wall as f64;
        rates[index].push(rate);
        let mut h = Sha256::new();
        for (i, &token) in tokens.iter().enumerate() {
            h.update((u64::from(token) | (((PRIME + i) as u64) << 32)).to_le_bytes());
            h.update(
                dsv4_pos_uniform(cfg.seed, PRIME + i + 1)
                    .to_bits()
                    .to_le_bytes(),
            );
            h.update(0u64.to_le_bytes());
        }
        println!(
            r#"MEASURE {{"row":{row},"dense_on":{on},"generated_tokens":256,"decode_wall_ns":{wall},"decode_tok_s":{rate},"first_capture":{first_capture},"timing_scope":"sample_plus_forward_envelope","eligible":true,"full_replay":true,"splitk":false,"generated_sha256":"{expected_tokens}","final_logits_sha256":"{}","final_cache_digest":{:?},"final_hidden_digest":{:?},"device_replays":{counts:?},"captures":[1,1],"control_sha256":"{:x}"}}"#,
            expected_identity.0,
            expected_identity.1,
            expected_identity.2,
            h.finalize()
        );
    }
    assert_eq!(first_capture_rows, [1, 1]);
    assert_eq!([rates[0].len(), rates[1].len()], [10, 10]);
    let pooled = walls.map(|w| 10.0 * OUTPUT as f64 * 1e9 / w as f64);
    let means = rates.map(|r| r.iter().sum::<f64>() / r.len() as f64);
    println!(
        r#"SUMMARY {{"rows":20,"off_pooled_tok_s":{},"on_pooled_tok_s":{},"off_mean_tok_s":{},"on_mean_tok_s":{},"pooled_delta_pct":{},"mean_delta_pct":{},"first_capture_rows_per_arm":[1,1],"identity":true,"decision":"return to root; no automatic merge or promotion"}}"#,
        pooled[0],
        pooled[1],
        means[0],
        means[1],
        100.0 * (pooled[1] / pooled[0] - 1.0),
        100.0 * (means[1] / means[0] - 1.0)
    );
    select(gpu, false);
}
fn main() {
    let args: Vec<_> = std::env::args().collect();
    assert!(
        args.len() == 4 || (args.len() == 5 && args[4] == "--reverse"),
        "usage: dsv4_dense_exact_tail_gate <model-dir> <source.txt> <new-output-dir> [--reverse]"
    );
    assert!(!dsv4_prof_on(), "unprofiled sampled envelope only");
    for (name, value) in [
        ("MEMRA_DSV4_DECODE_PATH", "device"),
        ("MEMRA_DSV4_EXPERT_ARM", "native"),
        ("MEMRA_DSV4_DENSE_ARM", "fp8"),
        ("MEMRA_DSV4_DOTS_ARM", "f32x"),
        ("MEMRA_DSV4_EP", "pair"),
        ("MEMRA_DSV4_MOE_PROGRAM", "matrix"),
        ("MEMRA_DSV4_GROUPED_ROUTE", "device"),
        ("MEMRA_DSV4_VERIFY_TOPK", "device"),
        ("MEMRA_DSV4_PREFILL_MOE", "reference"),
        ("MEMRA_DSV4_DRAFTER", "off"),
        ("MEMRA_DSV4_SMALL_KERNEL_DIET", "1"),
        ("MEMRA_MOE_F16G", "2"),
        ("MEMRA_F16G_SK", "32"),
    ] {
        assert_eq!(
            std::env::var(name).as_deref(),
            Ok(value),
            "requires {name}={value}"
        );
    }
    assert_eq!(dsv4_sampler().unwrap(), Dsv4Sampler::Device);
    // Pin the historical control program independently of the graph default.
    memra_engine::set_moe_m1_graph_splitk_for_gate(false);
    memra_engine::set_moe_m1_splitk_for_gate(false);
    assert!(!memra_engine::moe_m1_splitk_on());
    // This source pin contains neither cadence nor GU N32 implementation. The
    // controller binds the source; no future-default support is inferred.
    let source = std::fs::read_to_string(&args[2]).expect("source tape");
    assert_eq!(
        format!("{:x}", Sha256::digest(source.as_bytes())),
        SOURCE_SHA
    );
    let tokenizer = Tokenizer::from_hf_dir(Path::new(&args[1])).expect("tokenizer");
    let prompt = tokenizer.encode(
        &format!("Review this inference engine source:\n\n{source}"),
        true,
    );
    assert!(prompt.len() >= PRIME);
    let output = PathBuf::from(&args[3]);
    std::fs::create_dir(&output).expect("new output directory");
    Dsv4Gpu::set_tp_ep_topology_for_gate(true);
    Dsv4Gpu::set_attention_tp_for_gate(true);
    let gpu = Box::new(
        Dsv4Gpu::load(
            Path::new(&args[1]),
            &[0, 1],
            ActQuantVariant::RefFp8Round,
            PRIME + OUTPUT + 32,
        )
        .expect("pinned TP2 model"),
    );
    assert!(gpu.topology().is_tp_ep());
    assert_eq!(gpu.topology().layers, 43);
    assert!(gpu.attention_tp_geometry().is_some() && gpu.small_kernel_diet_enabled());
    gpu.set_grouped_route_validation_for_gate(false);
    gpu.set_grouped_mirror_validation_for_gate(false);
    gpu.set_grouped_gu_fuse_for_gate(true);
    gpu.set_grouped_m1_tc_for_gate(true);
    memra_engine::set_moe_f16g_gu_m1_tc_for_gate(true);
    memra_engine::set_moe_f16g_gu_half2_for_gate(true);
    memra_engine::set_moe_f16g_down_m1_half2_for_gate(true);
    gpu.set_dense_wo_a_grouped_for_gate(false);
    gpu.set_index_topk_radix_for_gate(true);
    run(&gpu, &prompt[..PRIME], &tokenizer, &output, args.len() == 5);
}