perf-网络协议栈性能分析

Linux perf:系统性能监控和分析工具 Linuxperf是 Linux 2.6+ 后内置于内核源码树中的性能剖析(profiling)工具,它基于事件采样,以性能事件为基础,针对 CPU 相关性能指标与操作系统相关性能指标进行性能剖析,可用于性能瓶颈查找与热点代码的定位。包含在 Linux 内核tools/perf下,通过命令perf实现一组子命令:stat , record , report ,[…] 阅读详情

分析 Linux 网络协议栈性能有多种方式和工具。本文主要通过 Perf 生成 On-CPU 火焰图的方式,分析 Linux 内核网络协议栈在特定场景下的性能瓶颈,从而知晓当前协议栈的网络状况。

文章相关视频详解:

深入浅出Linux内核网络协议栈

Linux内核内存管理专题训练营-学习视频

关于 On/Off-CPU

概念定义

1

2

3

On-CPU: where threads are spending time running on-CPU.

Off-CPU: where time is spent waiting while blocked on I/O, locks, timers, paging/swapping, etc.

 

On/Off-CPU 选择

在工程实践中,如果是 CPU 消耗型使用 On-CPU 火焰图,如果是 IO 消耗型则使用 Off-CPU 火焰图。如果无法确定, 可以通过压测工具来确认: 通过压测工具看能否让 CPU 使用率趋于饱和,从而判断是否为 CPU 消耗型。

分析方法

Perf 火焰图整个图形看起来就像一团跳动的火焰,这也正是其名字的由来。燃烧在火

滴滴Linux内核工程师笔试解析:从C语言到内核机制 操作系统底层原理是理解计算机系统运行的核心,其中进程调度、内存管理、并发同步等机制共同决定了系统的性能与稳定性。C语言作为内核开发的基础语言,其指针、内存对齐等知识点直接影响对底层实现的理解。掌握这些概念,不仅有助于分析内核源代码,还能在实际工程中定位性能瓶颈,例如通过ftrace、perf等工具优化高并发场景下的网络协议栈与块I/O路径。从通用技术原理出发,逐步深入到中断处理、文件系统等细节,能够构建完整的知识体系。本文以滴滴2018校招Linux内核工程师笔试为切入点,系统梳理了笔试中的高频考点与答题思 阅读详情

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