app.py

import gradio as gr
from transformers import AutoConfig
from typing import Dict, Any, Tuple, Optional
import math

def get_model_config(model_id: str) -> AutoConfig:
    """获取模型配置信息"""
    try:
        # 使用transformers的AutoConfig，更加可靠
        config = AutoConfig.from_pretrained(
            model_id, 
            trust_remote_code=True,  # 支持自定义模型
            revision="main"
        )
        return config
    except Exception as e:
        raise Exception(f"无法获取模型配置: {str(e)}")

def analyze_attention_mechanism(config: AutoConfig) -> Dict[str, Any]:
    """分析注意力机制类型"""
    model_type = getattr(config, "model_type", "").lower()
    architecture = getattr(config, "architectures", [])
    
    # 检测各种优化技术
    attention_info = {
        "uses_gqa": False,
        "uses_mla": False,
        "uses_sliding_window": False,
        "attention_type": "Multi-Head Attention (MHA)"
    }
    
    # 检测GQA (Grouped Query Attention)
    num_attention_heads = getattr(config, "num_attention_heads", getattr(config, "n_head", 0))
    num_key_value_heads = getattr(config, "num_key_value_heads", num_attention_heads)
    
    if num_key_value_heads < num_attention_heads and num_key_value_heads > 0:
        attention_info["uses_gqa"] = True
        attention_info["attention_type"] = "Grouped Query Attention (GQA)"
    
    # 检测MLA (Multi-head Latent Attention) - 主要在DeepSeek-V2等模型中
    if "deepseek" in model_type or any("deepseek" in str(arch).lower() for arch in architecture):
        if hasattr(config, "kv_lora_rank") or hasattr(config, "q_lora_rank"):
            attention_info["uses_mla"] = True
            attention_info["attention_type"] = "Multi-head Latent Attention (MLA)"
    
    # 检测滑动窗口注意力
    if hasattr(config, "sliding_window") or hasattr(config, "attention_window_size"):
        attention_info["uses_sliding_window"] = True
    
    # 特殊模型类型检测
    if "llama" in model_type:
        attention_info["attention_type"] = "RoPE + GQA" if attention_info["uses_gqa"] else "RoPE + MHA"
    elif "mistral" in model_type:
        attention_info["attention_type"] = "Sliding Window + GQA" if attention_info["uses_gqa"] else "Sliding Window + MHA"
    elif "qwen" in model_type:
        attention_info["attention_type"] = "QWen Attention (GQA)" if attention_info["uses_gqa"] else "QWen Attention"
    
    return attention_info

def calculate_kv_cache_size(config: AutoConfig, sequence_length: int = 2048, batch_size: int = 1) -> Dict[str, Any]:
    """计算KV cache大小"""
    
    # 获取基本参数，兼容不同的参数名
    num_layers = getattr(config, "num_hidden_layers", getattr(config, "n_layer", getattr(config, "num_layers", 0)))
    num_attention_heads = getattr(config, "num_attention_heads", getattr(config, "n_head", 0))
    num_key_value_heads = getattr(config, "num_key_value_heads", num_attention_heads)
    hidden_size = getattr(config, "hidden_size", getattr(config, "n_embd", getattr(config, "d_model", 0)))
    
    # 计算head dimension
    head_dim = hidden_size // num_attention_heads if num_attention_heads > 0 else 0
    
    # 如果是MLA，需要特殊处理
    kv_lora_rank = getattr(config, "kv_lora_rank", 0)
    if kv_lora_rank > 0:  # MLA架构
        # MLA中KV的维度被压缩
        effective_kv_dim = kv_lora_rank
    else:
        effective_kv_dim = head_dim * num_key_value_heads
    
    # 计算每个token的KV cache大小 (Key + Value)
    # 使用FP16 (2 bytes per element)
    bytes_per_element = 2
    kv_size_per_token_per_layer = 2 * effective_kv_dim * bytes_per_element  # K + V
    
    # 总的KV cache大小
    total_kv_cache_bytes = kv_size_per_token_per_layer * num_layers * sequence_length * batch_size
    
    # 转换为更友好的单位
    def format_bytes(bytes_val):
        if bytes_val < 1024:
            return f"{bytes_val} B"
        elif bytes_val < 1024**2:
            return f"{bytes_val/1024:.2f} KB"
        elif bytes_val < 1024**3:
            return f"{bytes_val/(1024**2):.2f} MB"
        else:
            return f"{bytes_val/(1024**3):.2f} GB"
    
    return {
        "num_layers": num_layers,
        "num_attention_heads": num_attention_heads,
        "num_key_value_heads": num_key_value_heads,
        "head_dim": head_dim,
        "hidden_size": hidden_size,
        "effective_kv_dim": effective_kv_dim,
        "kv_size_per_token": format_bytes(kv_size_per_token_per_layer * num_layers),
        "total_kv_cache": format_bytes(total_kv_cache_bytes),
        "total_kv_cache_bytes": total_kv_cache_bytes,
        "kv_lora_rank": kv_lora_rank
    }

def analyze_model(model_id: str, sequence_length: int = 2048, batch_size: int = 1) -> str:
    """分析模型并返回结果"""
    try:
        # 获取模型配置
        config = get_model_config(model_id)
        
        # 分析注意力机制
        attention_info = analyze_attention_mechanism(config)
        
        # 计算KV cache大小
        kv_info = calculate_kv_cache_size(config, sequence_length, batch_size)
        
        # 格式化输出
        result = f"""
## 模型信息分析 - {model_id}

        ### 基本参数
- **模型类型**: {getattr(config, 'model_type', 'Unknown')}
- **层数**: {kv_info['num_layers']}
- **隐藏层大小**: {kv_info['hidden_size']}
- **注意力头数**: {kv_info['num_attention_heads']}
- **KV头数**: {kv_info['num_key_value_heads']}
- **每个头的维度**: {kv_info['head_dim']}

### 注意力机制优化
- **注意力类型**: {attention_info['attention_type']}
- **使用GQA**: {'✅ 是' if attention_info['uses_gqa'] else '❌ 否'}
- **使用MLA**: {'✅ 是' if attention_info['uses_mla'] else '❌ 否'}
- **滑动窗口**: {'✅ 是' if attention_info['uses_sliding_window'] else '❌ 否'}

### KV Cache 存储分析
- **序列长度**: {sequence_length}
- **批量大小**: {batch_size}
- **有效KV维度**: {kv_info['effective_kv_dim']}
- **每个token的KV存储**: {kv_info['kv_size_per_token']}
- **总KV Cache大小**: {kv_info['total_kv_cache']}

### 优化效果分析
"""
        
        # 计算GQA的内存节省
        if attention_info['uses_gqa']:
            original_kv_heads = kv_info['num_attention_heads']
            actual_kv_heads = kv_info['num_key_value_heads']
            memory_reduction = (1 - actual_kv_heads / original_kv_heads) * 100
            result += f"- **GQA内存节省**: {memory_reduction:.1f}% (KV头数从{original_kv_heads}减少到{actual_kv_heads})\n"
        
        # MLA的特殊说明
        if attention_info['uses_mla']:
            result += f"- **MLA压缩**: KV维度被压缩到{kv_info['kv_lora_rank']}维\n"
        
        # 内存使用建议
        total_gb = kv_info['total_kv_cache_bytes'] / (1024**3)
        if total_gb > 8:
            result += f"\n⚠️ **内存警告**: KV Cache需要{total_gb:.2f}GB内存，建议使用高端GPU"
        elif total_gb > 4:
            result += f"\n💡 **内存提示**: KV Cache需要{total_gb:.2f}GB内存，中等配置可运行"
        else:
            result += f"\n✅ **内存友好**: KV Cache仅需{total_gb:.2f}GB内存"
            
        return result
        
    except Exception as e:
        return f"❌ 分析失败: {str(e)}"

# 创建Gradio界面
def create_interface():
    with gr.Blocks(title="Hugging Face模型KV Cache分析器", theme=gr.themes.Soft()) as iface:
        gr.Markdown("# 🤗 Hugging Face模型KV Cache分析器")
        gr.Markdown("输入模型ID来分析其KV cache大小和注意力机制优化情况")
        
        with gr.Row():
            with gr.Column(scale=3):
                model_input = gr.Textbox(
                    label="模型ID",
                    placeholder="例如: microsoft/DialoGPT-medium, meta-llama/Llama-2-7b-hf",
                    value="microsoft/DialoGPT-medium"
                )
            with gr.Column(scale=1):
                seq_len_input = gr.Number(
                    label="序列长度",
                    value=2048,
                    minimum=1,
                    maximum=131072
                )
            with gr.Column(scale=1):
                batch_size_input = gr.Number(
                    label="批量大小", 
                    value=1,
                    minimum=1,
                    maximum=128
                )
        
        analyze_btn = gr.Button("🔍 分析模型", variant="primary", size="lg")
        
        output = gr.Markdown(label="分析结果")
        
        # 添加一些示例模型
        gr.Markdown("### 💡 热门模型示例")
        example_models = [
            ["deepseek-ai/DeepSeek-V3-0324", 32768, 1],
            ["Qwen/Qwen3-8B", 32768, 1],
        ]
        
        gr.Examples(
            examples=example_models,
            inputs=[model_input, seq_len_input, batch_size_input],
            outputs=output,
            fn=analyze_model,
            cache_examples=False
        )
        
        analyze_btn.click(
            fn=analyze_model,
            inputs=[model_input, seq_len_input, batch_size_input],
            outputs=output
        )
        
        gr.Markdown("""
        ### 📖 说明
        - **GQA**: Grouped Query Attention，通过减少KV头数来节省内存
        - **MLA**: Multi-head Latent Attention，通过低秩分解压缩KV cache
        - **滑动窗口**: 限制注意力范围来减少计算和内存使用
        - KV Cache大小计算基于FP16精度 (每个元素2字节)
        - 使用 `transformers.AutoConfig` 获取配置，支持自定义模型
        
        ### 🛠️ 安装依赖
        ```bash
        pip install gradio transformers torch
        ```
        """)
    
    return iface

if __name__ == "__main__":
    app = create_interface()
    app.launch(share=True)