UNIX 系統性能

本教程的目的是引進性能分析師提供的免費工具，來監視和管理UNIX系統的性能，以及如何診斷和修復性能問題在Unix環境提供指引。

UNIX具有以下主要資源類型，需要進行監測和調整：

CPU
內存
磁盤空間
通信線路
I/O 時間
網絡時間
應用程序

性能組件：

有以下主要的五個組成部分的系統總時間的推移：

組件

描述

User state CPU

The actual amount of time the CPU spends running the users program in the user state. It includes time spent executing library calls, but does not include time spent in the kernel on its behalf.

System state CPU

This is the amount of time the CPU spends in the system state on behalf of this program. All I/O routines require kernel services. The programmer can affect this value by the use of blocking for I/O transfers.

I/O Time and Network Time

These are the amount of time spent moving data and servicing I/O requests

Virtual Memory Performance

This includes context switching and swapping.

Application Program

Time spent running other programs - when the system is not servicing this application because another application currently has the CPU.

性能工具：

UNIX提供了重要的工具來測量和微調Unix系統的性能：

命令

描述

nice/renice

Run a program with modified scheduling priority

netstat

Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

time

Time a simple command or give resource usage

uptime

System Load Average

Report a snapshot of the current processes.

vmstat

Report virtual memory statistics

gprof

Display call graph profile data

prof

Process Profiling

top

Display system tasks

您可以使用聯機幫助幫助這裏提到的每個命令的語法檢查完成。