simple_memory_calculator.py

from huggingface_hub import HfApi, hf_hub_download
from typing import Dict, Optional
import json
import os


class SimpleMemoryCalculator:
    def __init__(self):
        self.hf_api = HfApi()
        self.cache = {}
        
        # Known model memory requirements (in GB for FP16)
        self.known_models = {
            "black-forest-labs/FLUX.1-schnell": {
                "params_billions": 12.0,
                "fp16_gb": 24.0,
                "inference_fp16_gb": 36.0
            },
            "black-forest-labs/FLUX.1-dev": {
                "params_billions": 12.0,
                "fp16_gb": 24.0,
                "inference_fp16_gb": 36.0
            },
            "stabilityai/stable-diffusion-xl-base-1.0": {
                "params_billions": 3.5,
                "fp16_gb": 7.0,
                "inference_fp16_gb": 12.0
            },
            "runwayml/stable-diffusion-v1-5": {
                "params_billions": 0.86,
                "fp16_gb": 1.7,
                "inference_fp16_gb": 4.0
            }
        }
    
    def get_model_memory_requirements(self, model_id: str) -> Dict:
        """
        Get memory requirements for a model, using known values or estimating from file sizes.
        """
        if model_id in self.cache:
            return self.cache[model_id]
        
        # Check if we have known values
        if model_id in self.known_models:
            known = self.known_models[model_id]
            result = {
                'model_id': model_id,
                'total_params': int(known['params_billions'] * 1e9),
                'total_params_billions': known['params_billions'],
                'memory_fp32_gb': known['fp16_gb'] * 2,
                'memory_fp16_gb': known['fp16_gb'],
                'memory_bf16_gb': known['fp16_gb'],
                'memory_int8_gb': known['fp16_gb'] / 2,
                'estimated_inference_memory_fp16_gb': known['inference_fp16_gb'],
                'estimated_inference_memory_bf16_gb': known['inference_fp16_gb'],
                'source': 'known_values'
            }
            self.cache[model_id] = result
            return result
        
        # Try to estimate from HuggingFace API
        try:
            return self._estimate_from_api(model_id)
        except Exception as e:
            # Fallback to generic estimation
            return self._generic_estimation(model_id, str(e))
    
    def _estimate_from_api(self, model_id: str) -> Dict:
        """Estimate memory from HuggingFace model info."""
        try:
            print(f"Fetching model info for: {model_id}")
            model_info = self.hf_api.model_info(model_id)
            print(f"Successfully fetched model info for: {model_id}")
            
            # Get file sizes from model repo
            total_size_bytes = 0
            safetensor_files = []
            files_without_size = 0
            
            for sibling in model_info.siblings:
                if sibling.rfilename.endswith('.safetensors'):
                    file_size_bytes = sibling.size
                    if file_size_bytes is None or file_size_bytes == 0:
                        files_without_size += 1
                        print(f"Warning: No size info for {sibling.rfilename}")
                        # Try to estimate based on typical safetensor file sizes
                        if 'unet' in sibling.rfilename.lower():
                            file_size_bytes = 3_400_000_000  # ~3.4GB typical for UNet
                        elif 'text_encoder' in sibling.rfilename.lower():
                            file_size_bytes = 500_000_000   # ~500MB typical for text encoder
                        elif 'vae' in sibling.rfilename.lower():
                            file_size_bytes = 160_000_000   # ~160MB typical for VAE
                        else:
                            file_size_bytes = 500_000_000   # Default fallback
                        print(f"  → Using estimated size: {file_size_bytes / (1024**3):.2f} GB")
                    else:
                        print(f"File {sibling.rfilename}: {file_size_bytes / (1024**3):.2f} GB")
                    
                    size_mb = file_size_bytes / (1024 * 1024)
                    safetensor_files.append({
                        'filename': sibling.rfilename,
                        'size_mb': size_mb,
                        'estimated': file_size_bytes != sibling.size
                    })
                    total_size_bytes += file_size_bytes
            
            print(f"Found {len(safetensor_files)} safetensor files, total size: {total_size_bytes / (1024**3):.2f} GB")
            if files_without_size > 0:
                print(f"Warning: {files_without_size} files had no size info, used estimates")
            
            # Estimate parameters from file size (assuming FP16)
            total_size_gb = total_size_bytes / (1024**3)
            estimated_params = int((total_size_bytes / 2))  # 2 bytes per param for FP16
            estimated_params_billions = estimated_params / 1e9
            
            # Estimate inference memory (model + activations)
            inference_multiplier = 1.5  # Conservative estimate
            estimated_inference_memory = total_size_gb * inference_multiplier
            
            result = {
                'model_id': model_id,
                'total_params': estimated_params,
                'total_params_billions': estimated_params_billions,
                'memory_fp32_gb': total_size_gb * 2,
                'memory_fp16_gb': total_size_gb,
                'memory_bf16_gb': total_size_gb,
                'memory_int8_gb': total_size_gb / 2,
                'estimated_inference_memory_fp16_gb': estimated_inference_memory,
                'estimated_inference_memory_bf16_gb': estimated_inference_memory,
                'safetensors_files': safetensor_files,
                'files_without_size': files_without_size,
                'source': 'api_estimation'
            }
            
            self.cache[model_id] = result
            return result
            
        except Exception as api_error:
            print(f"API Error for model {model_id}: {type(api_error).__name__}: {str(api_error)}")
            # Re-raise with more context
            raise Exception(f"HuggingFace API Error: {type(api_error).__name__}: {str(api_error)}")                
    
    def _generic_estimation(self, model_id: str, error_msg: str) -> Dict:
        """Generic fallback estimation."""
        # Default to medium-sized model estimates
        default_params_billions = 3.0
        default_fp16_gb = 6.0
        
        return {
            'model_id': model_id,
            'total_params': int(default_params_billions * 1e9),
            'total_params_billions': default_params_billions,
            'memory_fp32_gb': default_fp16_gb * 2,
            'memory_fp16_gb': default_fp16_gb,
            'memory_bf16_gb': default_fp16_gb,
            'memory_int8_gb': default_fp16_gb / 2,
            'estimated_inference_memory_fp16_gb': default_fp16_gb * 1.5,
            'estimated_inference_memory_bf16_gb': default_fp16_gb * 1.5,
            'source': 'generic_fallback',
            'error': error_msg
        }
    
    def get_memory_recommendation(self, model_id: str, available_vram_gb: float) -> Dict:
        """Get memory recommendations based on available VRAM."""
        memory_info = self.get_model_memory_requirements(model_id)
        
        recommendations = {
            'model_id': model_id,
            'available_vram_gb': available_vram_gb,
            'model_memory_fp16_gb': memory_info['memory_fp16_gb'],
            'estimated_inference_memory_fp16_gb': memory_info['estimated_inference_memory_fp16_gb'],
            'recommendations': []
        }
        
        inference_memory_fp16 = memory_info['estimated_inference_memory_fp16_gb']
        model_memory_fp16 = memory_info['memory_fp16_gb']
        
        # Determine recommendations
        if available_vram_gb >= inference_memory_fp16:
            recommendations['recommendations'].append("✅ Full model can fit in VRAM")
            recommendations['recommended_precision'] = 'float16'
            recommendations['cpu_offload'] = False
            recommendations['attention_slicing'] = False
            
        elif available_vram_gb >= model_memory_fp16:
            recommendations['recommendations'].append("⚠️ Model weights fit, enable memory optimizations")
            recommendations['recommended_precision'] = 'float16'
            recommendations['cpu_offload'] = False
            recommendations['attention_slicing'] = True
            recommendations['vae_slicing'] = True
            
        elif available_vram_gb >= model_memory_fp16 * 0.7:
            recommendations['recommendations'].append("🔄 Use CPU offloading for some components")
            recommendations['recommended_precision'] = 'float16'
            recommendations['cpu_offload'] = True
            recommendations['attention_slicing'] = True
            recommendations['vae_slicing'] = True
            
        else:
            recommendations['recommendations'].append("🔄 Requires sequential CPU offloading")
            recommendations['recommended_precision'] = 'float16'
            recommendations['sequential_offload'] = True
            recommendations['attention_slicing'] = True
            recommendations['vae_slicing'] = True
        
        return recommendations
    
    def format_memory_info(self, model_id: str) -> str:
        """Format memory information for display."""
        info = self.get_model_memory_requirements(model_id)
        
        source_text = {
            'known_values': '📊 Known model specifications',
            'api_estimation': '🔍 Estimated from model files',
            'generic_fallback': '⚠️ Generic estimation (API error)'
        }.get(info.get('source', 'unknown'), '❓ Unknown source')
        
        # Add warning if file sizes were estimated
        if info.get('files_without_size', 0) > 0:
            source_text += f" (⚠️ {info['files_without_size']} files used size estimates)"
        
        output = f"""
🤖 **Memory Analysis for {model_id}**

{source_text}

🔢 **Parameters**: {info['total_params_billions']:.1f}B parameters

💾 **Model Memory Requirements**:
   • FP32: {info['memory_fp32_gb']:.1f} GB
   • FP16/BF16: {info['memory_fp16_gb']:.1f} GB
   • INT8: {info['memory_int8_gb']:.1f} GB

🚀 **Estimated Inference Memory**:
   • FP16: {info['estimated_inference_memory_fp16_gb']:.1f} GB
   • BF16: {info['estimated_inference_memory_bf16_gb']:.1f} GB
"""
        
        if 'error' in info:
            output += f"\n⚠️ **Note**: {info['error']}"
        
        return output.strip()


# Quick test
if __name__ == "__main__":
    calc = SimpleMemoryCalculator()
    
    models = [
        "black-forest-labs/FLUX.1-schnell",
        "stabilityai/stable-diffusion-xl-base-1.0",
        "runwayml/stable-diffusion-v1-5"
    ]
    
    for model in models:
        print(f"\n{'='*60}")
        print(calc.format_memory_info(model))
        
        # Test recommendations
        for vram in [8, 16, 24]:
            rec = calc.get_memory_recommendation(model, vram)
            print(f"\n💡 {vram}GB VRAM: {rec['recommendations'][0]}")