LLM并行处理实践：性能增强的关键技术-Python教程-PHP中文网

LLM Parallel Processing in Practice: Key Techniques for Performance Enhancement

要点

掌握LLM申请中的并行处理策略
实施高效的批处理机制
构建可扩展的文档处理系统
优化系统性能和资源利用率

并行处理用例

在LLM应用中，并行处理特别适合：

批量文档处理
多模型并行推理
大规模数据分析
实时流处理

批处理策略设计

1. 基本架构

from typing import List, Dict, Any
from dataclasses import dataclass
import asyncio
from langchain.chat_models import ChatOpenAI
from langchain.callbacks import AsyncCallbackHandler

@dataclass
class BatchConfig:
    """Batch processing configuration"""
    batch_size: int = 5
    max_concurrent_tasks: int = 3
    timeout_seconds: int = 30
    retry_attempts: int = 2

class BatchProcessor:
    def __init__(self, config: BatchConfig):
        self.config = config
        self.llm = ChatOpenAI(
            temperature=0,
            request_timeout=config.timeout_seconds
        )
        self.semaphore = asyncio.Semaphore(
            config.max_concurrent_tasks
        )

    async def process_batch(
        self, 
        items: List[Any]
    ) -> List[Dict]:
        """Main batch processing function"""
        batches = self._create_batches(items)
        results = []

        for batch in batches:
            batch_results = await self._process_batch_with_semaphore(
                batch
            )
            results.extend(batch_results)

        return results

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2. 异步处理实现

class AsyncBatchProcessor(BatchProcessor):
    async def _process_single_item(
        self, 
        item: Any
    ) -> Dict:
        """Process single item"""
        async with self.semaphore:
            for attempt in range(self.config.retry_attempts):
                try:
                    return await self._execute_processing(item)
                except Exception as e:
                    if attempt == self.config.retry_attempts - 1:
                        return self._create_error_response(item, e)
                    await asyncio.sleep(2 ** attempt)

    async def _execute_processing(
        self, 
        item: Any
    ) -> Dict:
        """Execute specific processing logic"""
        task = asyncio.create_task(
            self.llm.agenerate([item])
        )
        try:
            result = await asyncio.wait_for(
                task,
                timeout=self.config.timeout_seconds
            )
            return {
                "status": "success",
                "input": item,
                "result": result
            }
        except asyncio.TimeoutError:
            task.cancel()
            raise

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真实案例：批量文档处理系统

1. 系统架构

class DocumentBatchProcessor:
    def __init__(self):
        self.config = BatchConfig(
            batch_size=10,
            max_concurrent_tasks=5
        )
        self.processor = AsyncBatchProcessor(self.config)
        self.results_manager = ResultsManager()

    async def process_documents(
        self, 
        documents: List[str]
    ) -> Dict:
        """Process document batches"""
        try:
            preprocessed = await self._preprocess_documents(
                documents
            )
            results = await self.processor.process_batch(
                preprocessed
            )
            return await self.results_manager.merge_results(
                results
            )
        except Exception as e:
            return self._handle_batch_error(e, documents)

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2. 资源控制机制

class ResourceController:
    def __init__(self):
        self.token_limit = 4096
        self.request_limit = 100
        self._request_count = 0
        self._token_count = 0
        self._reset_time = None

    async def check_limits(self) -> bool:
        """Check resource limits"""
        await self._update_counters()
        return (
            self._request_count < self.request_limit and
            self._token_count < self.token_limit
        )

    async def track_usage(
        self, 
        tokens_used: int
    ):
        """Track resource usage"""
        self._token_count += tokens_used
        self._request_count += 1

    async def wait_if_needed(self):
        """Wait for resource release if necessary"""
        if not await self.check_limits():
            wait_time = self._calculate_wait_time()
            await asyncio.sleep(wait_time)

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3. 结果合并策略

class ResultsManager:
    def __init__(self):
        self.merge_strategies = {
            "text": self._merge_text_results,
            "embeddings": self._merge_embedding_results,
            "classifications": self._merge_classification_results
        }

    async def merge_results(
        self, 
        results: List[Dict]
    ) -> Dict:
        """Merge processing results"""
        merged = {
            "success_count": 0,
            "error_count": 0,
            "results": []
        }

        for result in results:
            if result["status"] == "success":
                merged["success_count"] += 1
                merged["results"].append(
                    await self._process_result(result)
                )
            else:
                merged["error_count"] += 1

        return merged

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性能优化指南

1. 内存管理

class MemoryManager:
    def __init__(self, max_memory_mb: int = 1024):
        self.max_memory = max_memory_mb * 1024 * 1024
        self.current_usage = 0

    async def monitor_memory(self):
        """Monitor memory usage"""
        import psutil
        process = psutil.Process()
        memory_info = process.memory_info()

        if memory_info.rss > self.max_memory:
            await self._trigger_memory_cleanup()

    async def _trigger_memory_cleanup(self):
        """Trigger memory cleanup"""
        import gc
        gc.collect()

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2. 性能监控

class PerformanceMonitor:
    def __init__(self):
        self.metrics = {
            "processing_times": [],
            "error_rates": [],
            "throughput": []
        }

    async def record_metrics(
        self, 
        batch_size: int, 
        duration: float, 
        errors: int
    ):
        """Record performance metrics"""
        self.metrics["processing_times"].append(duration)
        self.metrics["error_rates"].append(errors / batch_size)
        self.metrics["throughput"].append(
            batch_size / duration
        )

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