41 lines
1.4 KiB
Markdown
41 lines
1.4 KiB
Markdown
---
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title: "Performance Contracts"
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type: concept
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tags: [performance, latency, engineering]
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sources: [lsp-index-engineer]
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last_updated: 2026-04-25
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---
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## Definition
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性能契约（Performance Contracts）是 LSP/Index Engineer 定义的量化性能约束体系，为 graphd 系统的每个关键操作设定明确的延迟、吞吐量和资源上限，作为所有实现决策的北极星指标。
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## Contract Table
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| Operation | Constraint | Notes |
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|-----------|-----------|-------|
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| `/graph` endpoint | <100ms | 数据集 <10k 节点 |
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| `/nav/:symId` (cached) | <20ms | 缓存命中 |
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| `/nav/:symId` (uncached) | <60ms | 缓存未命中 |
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| WebSocket event stream | <50ms latency | 端到端推送延迟 |
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| Memory usage | <500MB | 典型项目 |
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| Go-to-definition | <150ms | 任意符号 |
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| Hover documentation | <60ms | 悬停响应 |
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| Graph update propagation | <500ms | 文件保存后 |
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| Symbol scale | 100k+ symbols | 无性能降级 |
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## Measurement Strategy
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- **基准测试**：每次提交后运行基准测试套件
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- **Profiling**：识别性能瓶颈并优先处理
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- **P99 监控**：关注 P99 而非平均值，确保长尾性能
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## Optimization Techniques
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- 内存映射文件（Memory-mapped files）
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- 零拷贝网络传输（io_uring）
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- 无锁数据结构（Lock-free data structures）
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- SIMD 优化图操作
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- 批量 LSP 请求以减少往返开销
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- 主动缓存 + 精确失效
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