what-pid

Lightweight Linux process monitor with NFS vs local disk detection.

A production-ready tool for monitoring CPU, memory, and disk I/O on Linux servers. Reads directly from /proc - no external dependencies.

Quick Install

pip install git+https://github.com/DaronPopov/what_pid.git

Usage

what-pid

Or use the alias:

sysmon

Options

Option	Description
-i, --interval SEC	Refresh interval (default: 2.0, range: 0.5-60)
-n, --limit NUM	Max processes to display (default: auto-fit)
-h, --help	Show help
-v, --version	Show version

Examples

what-pid              # Default: 2s refresh, auto-fit display
what-pid -i 1         # 1 second refresh
what-pid -n 50        # Show top 50 processes
what-pid -i 1 -n 30   # Fast refresh, 30 processes

Display

System Monitor - server01 - 14:32:01 - up 5d 12h 30m

CPU [128]: [||||||||||||             ]  48.2%  (us: 30.1% sy: 18.1% wa: 0.0%)
Mem:       [||||||                   ]  25.3%  (128.5G / 512.0G, 383.5G free)
Load avg:  8.12  7.45  6.23   (1m / 5m / 15m)

-----------------------------------------------------------
    PID     CPU%       MEM        READ       WRITE     DISK
-----------------------------------------------------------
  12345    156.2      2.3G   125.4 MB/s    45.2 MB/s   LOCAL
  12346     89.1      1.1G     0.0  B/s     0.0  B/s     NFS

Columns

Column	Description
PID	Process ID
CPU%	CPU usage (100% = 1 core, can exceed on multi-threaded)
MEM	Resident memory (M/G/T)
READ/WRITE	Disk I/O rates
DISK	LOCAL, NFS, or UNKNOWN

Features

• Zero dependencies - Python standard library only
• Multi-core aware - Correctly handles 100+ core Xeon servers
• Large memory support - Displays TB for high-memory servers
• NFS detection - Identifies processes using NFS vs local disk
• Production ready - Handles 1000+ processes efficiently
• Clean display - Auto-fits terminal, smooth refresh

Requirements

• Linux (kernel 4.x+)
• Python 3.6+
• No root required (some metrics need root for full visibility)

How It Works

Reads directly from /proc:

Source	Data
/proc/[pid]/stat	CPU ticks
/proc/[pid]/status	Memory (VmRSS)
/proc/[pid]/io	Disk I/O counters
/proc/[pid]/fd/	File descriptors
/proc/stat	System CPU
/proc/meminfo	System memory
/proc/self/mountinfo	Mount points (NFS detection)

No shell commands (ps, top, df) are used.

License

MIT