Model Compression: Bringing LLMs Everywhere
With advanced compression techniques, compress tens-of-GB LLMs down to MB scale while maintaining performance, enabling AI to run on phones, edge devices, and even embedded systems.
Core Compression Techniques
🔢 Quantization
- • INT8/INT4 quantization
- • Mixed-precision quantization
- • Dynamic quantization
- • Quantization-aware training
✂️ Model Pruning
- • Structured pruning
- • Unstructured pruning
- • Dynamic sparsity
- • Channel pruning
📚 Knowledge Distillation
- • Teacher–student models
- • Self-distillation
- • Feature distillation
- • Relation distillation
🔄 Low-rank Factorization
- • Matrix factorization
- • LoRA adapters
- • SVD
- • Tucker decomposition
Quantization in Detail
Performance Comparison: FP32 → INT4
import torch
import torch.nn as nn
from transformers import AutoModel
class QuantizationEngine:
"""Model quantization engine"""
def quantize_model(self, model, quantization_config):
"""Perform model quantization"""
# 1. Collect calibration data
calibration_data = self.collect_calibration_data(model)
# 2. Compute quantization parameters
quant_params = self.calculate_quantization_params(
model,
calibration_data,
method=quantization_config['method'] # 'symmetric' or 'asymmetric'
)
# 3. Apply quantization
if quantization_config['bits'] == 8:
quantized_model = self.int8_quantization(model, quant_params)
elif quantization_config['bits'] == 4:
quantized_model = self.int4_quantization(model, quant_params)
# 4. Quantization-aware fine-tuning (optional)
if quantization_config.get('qat', False):
quantized_model = self.quantization_aware_training(
quantized_model,
training_data=quantization_config['training_data']
)
return quantized_model
def benchmark_quantization(self, original_model, quantized_model):
"""Performance benchmark test"""
results = {
'model_size': {
'original': self.get_model_size(original_model), # 13GB
'quantized': self.get_model_size(quantized_model), # 3.2GB
'compression_ratio': '4.1x'
},
'inference_speed': {
'original': self.measure_latency(original_model), # 245ms
'quantized': self.measure_latency(quantized_model), # 62ms
'speedup': '3.9x'
},
'accuracy': {
'original': self.evaluate_accuracy(original_model), # 92.5%
'quantized': self.evaluate_accuracy(quantized_model), # 91.8%
'degradation': '-0.7%'
}
}
return resultsQuantization Results Comparison
| Precision | Model Size | Inference Latency | Accuracy | Memory Usage |
|---|---|---|---|---|
| FP32 (original) | 13GB | 245ms | 92.5% | 16GB |
| FP16 | 6.5GB | 125ms | 92.3% | 8GB |
| INT8 | 3.2GB | 62ms | 91.8% | 4GB |
| INT4 | 1.6GB | 35ms | 89.2% | 2GB |
Knowledge Distillation
Teacher–Student Architecture
Distillation Process
🎓 Teacher Model
- • Parameters: 175B
- • Layers: 96
- • Hidden size: 12288
- • Accuracy: 95.2%
👶 Student Model
- • Parameters: 1.3B
- • Layers: 24
- • Hidden size: 2048
- • Target accuracy: > 90%
Distillation Strategies
1Soft-label distillation: transfer teacher probability distribution
2Feature distillation: match intermediate representations
3Attention distillation: learn attention patterns
Model Pruning Techniques
Structured Pruning in Practice
Pruning Results Analysis
Attention head pruningRemove 30% redundant heads
FFN layer pruningCompress 40% neurons
Layer pruningRemove 6 redundant layers
-65%
Parameters reduced
2.8x
Speedup
-2.1%
Accuracy drop
Edge Deployment Optimization
Mobile Deployment Solutions
Deployment Architecture Comparison
☁️ Cloud
- • Latency: 200–500ms
- • Cost: $0.01/request
- • Privacy: Data uploaded
- • Reliability: Network-dependent
🖥️ Edge server
- • Latency: 20–50ms
- • Cost: $0.001/request
- • Privacy: Local processing
- • Reliability: High availability
📱 On-device
- • Latency: < 10ms
- • Cost: $0
- • Privacy: Fully local
- • Reliability: Works offline
Real-world Case Studies
Mobile Keyboard AI
Compression Strategy
INT8 quantization + knowledge distillation + structured pruning
Results
- • Model size: 2GB → 45MB
- • Response time: < 5ms
- • Accuracy retained: 95%
In-vehicle Voice Assistant
Compression Strategy
Mixed-precision quantization + LoRA fine-tuning
Results
- • Deployment chip: Qualcomm 8155
- • Power consumption reduced: 70%
- • Offline recognition rate: 92%
Choosing Compression Techniques
Best Practices by Scenario
📱 Mobile applications
Recommend: INT8 + distillation; keep model size under 100MB
🚗 Embedded devices
Recommend: INT4 + aggressive pruning; fit tight compute budgets
🖥️ Edge servers
Recommend: FP16 + structured pruning to balance performance and accuracy