Comprehensive evaluation across TOFU, MUSE, and WMDP benchmarks
Token-level softmax probabilities on forget sets — how well does each model memorize its training data?
Pretrained knowledge (forget data in pretraining only)
Knowledge injected via fine-tuning
Mean token probability by position — 100 examples per category
shaded = ±1 std · QA: position 0 = first answer token
Token probability density + average vocabulary rank per bin
colored curve = KDE density (left axis) · white bars + curve = avg rank (right axis, needs rerun) · gold dashed = mean · purple dotted = median
Domain
Task
Color mode
P =50%bottom-P% by prob = selected for demotion
L =chunk_size (L tokens per training sample)S =skip_tokens (context prefix, no loss)
lowhigh
Mean token probability vs duplication level —
MUSE News — Token Probability Analysis
Llama-2-7b-hf continued-pretrained on 300 news articles. The "full model" stores high verbatim memory for these articles — this view would show per-token softmax probabilities on forget set texts.
Models fine-tuned on 200 fictional author biographies and Q&A pairs. The forget set (forget10 = 200 authors, 10% of all) is memorized via SFT. Q&A format means individual answer tokens carry very high probability.
Real-World Knowledge Unlearning benchmark. 200 Wikipedia entities (people, organizations) the model knows from pretraining. Unlike TOFU, memorization comes from pretraining data, not explicit fine-tuning.
Weapons of Mass Destruction Proxy benchmark. Hazardous biosecurity and chemistry knowledge from pretraining. Measured as MCQ accuracy; token probs on answer choices reflect the model's "confidence" in dangerous knowledge.
Full Model vs Retain90 (gold) vs SHRED P=50 — why SHRED achieves higher MU
Key Insight
SHRED P=50 achieves MU=0.637 — higher than the full model (0.627).
Truth Ratio = P(correct) / (P(correct) + P(perturbed)) Measures calibration: can the model distinguish real answers from paraphrased versions? 0.5 = random, higher = better.
Why MU is higher: The full model is over-memorized. SHRED redistributes logits, improving calibration:
• Truth Ratio ↑ across all splits — especially ra (+0.04) and wf (+0.09)
• Probability ↑ on ra/wf — model becomes more confident on retain knowledge
• ROUGE ↓ on retain (0.769 vs 0.982) — less verbatim memorization
MU = harmonic mean across splits. SHRED's better calibration compensates for lower raw ROUGE, yielding a higher overall MU.
Training Convergence — P=50%, LR=1e-5, by Batch Size
Wall-clock time vs metrics at each checkpoint
Training step vs metrics at each checkpoint
Privacy Leak (MIA) vs Step — TOFU ShredFF (P=50%, LR=1e-5)
Fixed slice P=50%, LR=1e-5 across BS ∈ {1,2,4,8,20,40}. Each line = one config.
Optimal = 0. Negative = under-unlearned, Positive = over-unlearned. Dashed lines = baselines.
Real-World Knowledge Unlearning | 200 famous people, zero-shot entity removal | LLaMA-3-8B-Instruct | Baselines from RWKU paper (Jin et al. 2024)
Baseline Performance — Meta-Llama-3-8B-Instruct — "Before (ours)" = our eval pipeline on the base model; other rows are from the RWKU paper (different eval protocol, not directly comparable)
Method
Forget ↓
Neighbor ↑
MIA
Utility ↑
FB
QA
AA
All
FB
QA
All
FM↑
RM↓
Gen
Rea
Tru
Fac
Flu
Key Observations
• ICU best forget (All: 12.8) but destroys neighbors (55.7 vs 90.7)
• NPO (Full) best trainable method (All: 26.2) with decent neighbors (72.6)
• GA* catastrophic MIA scores (1640.9) — over-optimization
• LoRA variants consistently underperform Full across all methods
• All methods trade neighbor quality for forgetting — SHRED may offer better locality
Benchmark Comparison
Criteria
TOFU
MUSE
RWKU
Targets
—
2
200
Forget Probes
4,000
220
13,131
Real-World
✗
✓
✓
Zero-Shot
✗
✗
✓
Adversarial
✗
✗
✓
Neighbor
✓
✗
✓
MIA
✗
✗
✓
Multi-scenario memorization benchmark — Copyright, Privacy, Test contamination
Hubble(C) — Copyright
passages_gutenberg_popular • paraphrases_paws
⏳ Not yet started
Hubble(P) — Privacy
biographies_yago • chats_personachat
⏳ Not yet started
Hubble(T) — Test Contamination
testset_MMLU • testset_ellie
⏳ Not yet started
Robustness to relearning — can the unlearned model recover forgotten knowledge via fine-tuning?
Relearning Attack Protocol
Take unlearned model (SHRED, GradAscent, GradDiff, NPO, RMU)
Fine-tune on forget set with LR ∈ {1e-6, 5e-6, 1e-5} for 1–5 epochs
Eval forget_prob at each epoch → recovery curve
Steeper recovery = weaker unlearning
⏳ Not yet started
⏳ Relearning curve — epochs vs forget_prob recovery
Continual learning after unlearning — does forgetting persist when the model learns new knowledge?
Continual Learning Protocol
Unlearn with SHRED (P=50, best config) on forget10
Continue training on retain/holdout data
Measure: forget_prob stays low, MU doesn’t degrade
Compare: do baselines retain unlearning after new learning?
⏳ Not yet started
⏳ Continual learning — training steps vs forget_prob / MU
DESIGN
Document tiled into non-overlapping [T context] + [C target] windows, stride = T+C (no overlap, no wasted tokens).
Loss and SHRED demotion applied only to target. Standard causal attention — no custom mask needed.
Currently running: T=128, C=256 (stride=384).
Document tiled into non-overlapping L-token chunks. Full causal attention, KL loss on all positions.
First S tokens per chunk excluded from P%-demotion selection (limited context → unreliable probabilities).
Currently running: L ∈ {128, 512, 2048}, S ∈ {0, 8, 32}.
Precompute only — bidirectional (no causal mask) forward pass on each L-token chunk to compute selection probabilities.
Each token's probability is conditioned on all surrounding tokens (past and future), not just past tokens.
This removes position bias entirely: early tokens no longer appear artificially harder.
Training still uses standard causal attention — only the selection step is non-causal.
Token probability by position — context size comparison
How much context each token sees determines prediction confidence and SHRED signal strength.
Autoregressive = full causal (growing context, position bias). Sliding window-8 = every token sees exactly 8 prior tokens. T=128 ShredLong = every target token sees exactly 128 prior tokens (data pending).
Attention mask grid
Rows = query token, Columns = key token. Each cell: attended (filled) or blocked (−∞).
Cell meaning
Attends (0 in additive mask)
Blocked (−∞ in additive mask)
Token regions
Context (T tokens) — no loss
Target (C tokens) — SHRED demotion
Key property: every target token attends to
exactly T prior tokens — eliminating the position bias that would otherwise
make early tokens appear harder to predict.
Context rows use standard causal attention
(growing window). Target rows use a fixed
T-wide sliding window.
SHRED on QA datasets — coming soon.
SHRED Unlearning — Resource requirements
GPU requirements per training run
One SHRED run = 50 epochs on MUSE News forget set (~2K sequences). Lower bound: QLoRA (4-bit base + LoRA r=32) + 8-bit Adam. Upper bound: full BF16 fine-tune with AdamW FP32 master states + FSDP.
To complete the paper's planned experiments (full model × benchmark × method matrix + ablations on robustness, relearning attacks, sequential unlearning, and scaling laws), we estimate:
Experiment category
Configs
GPU-hours
Timeline (GC A100)
Complete MUSE grid (Books + News) all models
~160 runs
3,200
~3 weeks on 8× A100
TOFU sequential unlearning (forget01 → 05 → 10)
~60 runs
400
~3 days on 8× A100
Relearning attack robustness (k% sweep)
~100 runs
500
~4 days on 8× A100
WMDP bio+cyber × methods
~40 runs
800
~1 week on 8× A100
RWKU 200-entity sweep
~80 runs
1,600
~2 weeks on 8× A100
Scaling: SHRED on 13B/70B (future work)
~30 runs
2,000
~2 weeks on 8× H100
TOTAL planned
~470 runs
~8,500 GPU-h
~6-8 weeks on 8× A100
Scaling to Larger Models — GPU Requirements
Estimated GPU setup to train SHRED on frontier open-weight models. Lower bound: QLoRA (4-bit base + LoRA adapters, r=32) + 8-bit Adam — memory-optimized, quality trade-off acceptable for unlearning.
Upper bound: full BF16 fine-tuning with AdamW in FP32 — paper-quality results, reference-grade.
Memory accounting: weights + gradients + optimizer state (2× weights for Adam) + activations.
Model
Params
LoRA + 8-bit (lower bound)
Full BF16 (upper bound)
GPU setup
Peak mem
GPU-h / run
GPU setup
Peak mem
GPU-h / run
Gemma 4 31B
31 B
1× A100 80G
~32 GB
~28h
4× H100 80G (FSDP)
~370 GB
~70h
Llama 3.3 70B
70.6 B
1× H100 80G
~52 GB
~60h
8-16× H100 80G (FSDP+offload)
~840 GB
~160h
Llama 3.1 405B
405 B
4× H100 80G (FSDP)
~260 GB
~240h
64× H100 80G (multi-node FSDP)
~4.8 TB
~600h
GPU-hours estimated on the MUSE News forget set (~2K sequences, 50 epochs). Linear scaling with # chunks. Multi-GPU numbers include communication overhead (~15-25% vs ideal).
LoRA path enables rapid iteration & ablation; full BF16 path gives the reference numbers for the paper's scaling claim. Running both for Gemma 2 9B (~1,260 h total) provides a LoRA-vs-full comparison to validate the QLoRA-SHRED path on smaller model before committing H100 budget on 70B+.
Why Scale Up
Problem: Regulatory frameworks (GDPR Art. 17, EU AI Act) require deployed LLMs to support right-to-be-forgotten requests. Retraining from scratch on a 70B model costs millions. Current unlearning methods either destroy utility or leak private data via MIA.
Contribution:SHRED achieves competitive forgetting with no retain data, matches specialized methods on MIA leakage (~0), and discovers a principled small-batch-is-better phenomenon. The self-distillation framing generalizes naturally to continual learning (SDFT) and RL (SDPO).
What scale-up enables:
Production-scale validation: Gemma 27B / Llama 70B / 405B on real deployment data (currently bottlenecked at 7B by single-GPU memory)
Online unlearning: stream of forget requests over days — requires sustained training infrastructure
Adversarial robustness: relearning attacks need many fine-tuning rounds per unlearned model
Cross-domain transfer: code, medical, legal, multilingual — each needs separate grid sweeps
LoRA-vs-full comparison: establish whether parameter-efficient unlearning preserves SHRED's MIA guarantees — key practical question for deployers