Master Linux Performance Monitoring: nmon, perf, top, iostat, sar, dstat & htop

Overview

Using a Huawei Kunpeng server, you can monitor system performance with several Linux tools.

1. nmon

Collects CPU, disk, network, memory usage over a period.

2. perf

Built‑in Linux kernel tool that captures per‑process call information and CPU consumption, and can generate flame graphs.

Flame‑graph generation steps:

Trace the system to obtain profiling data.

Use a script to draw the graph.

git clone https://github.com/brendangregg/FlameGraph

3. top

Monitors processes and overall CPU/memory usage, showing per‑CPU core utilization.

Typical fields displayed:

Load: time, logged‑in users, average load.

CPU: user, system, nice, idle, iowait, interrupt, etc.

Process: running, sleeping, stopped, zombie.

Memory: total, used, free, buffers, cache.

Swap: total, used, free.

Task area shows PID, user, priority, nice, virtual/physical/shared memory, state, CPU% and MEM%, cumulative CPU time, command line.

4. iostat

Monitors read/write counts, data volume, and utilization for each disk.

Install via the sysstat package:

yum -y install sysstat

5. sar

System Activity Reporter, a comprehensive Linux performance analysis tool that monitors network I/O per NIC.

Install after installing deltarpm:

yum install deltarpm</code>
<code>yum install sysstat

6. dstat

Shows overall system performance information (CPU, disk, network, paging) with colored, readable output.

Install:

yum install dstat-0.7.2-12.el7 -y

7. htop

Interactive process viewer with color themes, mouse support, and scrollable process list.

Install: yum install -y htop Advantages:

Starts faster than top.

Horizontal and vertical scrolling to view all processes and full command lines.

Kills processes without needing to type the PID.

Supports mouse operations.