DTOP — .NET Process Monitor

A lightweight, cross-platform terminal process monitor written in C# / .NET 8. Displays real-time CPU, memory, thread count, and status for all running processes with smooth diff-based rendering, configurable color thresholds, and multi-channel alerting via OS notifications, Growl (GNTP), and email.

──────────────────────────────────────────────────────────────────────────────────
  DTOP — .NET Process Monitor  Windows 11 (build 22621) [X64]
──────────────────────────────────────────────────────────────────────────────────
  Cores 8  |  RAM 16,384 MB
  Notif: ON  Growl: OFF  Email: OFF
──────────────────────────────────────────────────────────────────────────────────
  Sort: C-cpu  M-mem  I-pid  E-name  H-threads  S-status  |  A-asc  D-desc
  Toggle: N-notif  G-growl  L-email  |  P-pause  T-test  R-reload  Q-quit
──────────────────────────────────────────────────────────────────────────────────
  CPU [████████░░░░░░░░░░░░░░░░░░]  28.4%
  MEM [█████████████████░░░░░░░░░]  68.1%  (11,140 / 16,384 MB)

  PID     Process Name                 CPU %▼    Mem MB    Threads  Status
  ────────────────────────────────────────────────────────────────────────────────
     1623  webpack                      22.31%       380        6    running
     1500  java                          8.70%       512       28    running
      701  python3                      12.40%        95        2    running
      312  nginx                         1.20%        24        4    running

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Requirements

• .NET 8 SDK or later
• Windows 10+, macOS, or Linux (any modern distro)
• A terminal that supports ANSI escape codes and UTF-8
  • Windows: Windows Terminal (recommended), PowerShell 7, or cmd.exe on Win10+
  • macOS: Terminal.app, iTerm2
  • Linux: any VTE-based terminal (GNOME Terminal, Konsole, Alacritty, etc.)

---

Quick Start

# Clone or extract the project
cd DotnetHtop

# Run directly (auto-restores packages)
dotnet run

---

Build

Development

dotnet build
dotnet run

Self-contained release binary

Produces a single executable with no .NET runtime dependency on the target machine.

# Windows x64
dotnet publish -c Release -r win-x64 --self-contained true -o ./out

# Windows ARM64
dotnet publish -c Release -r win-arm64 --self-contained true -o ./out

# macOS x64 (Intel)
dotnet publish -c Release -r osx-x64 --self-contained true -o ./out

# macOS ARM64 (Apple Silicon)
dotnet publish -c Release -r osx-arm64 --self-contained true -o ./out

# Linux x64
dotnet publish -c Release -r linux-x64 --self-contained true -o ./out

# Linux ARM64 (Raspberry Pi, cloud VMs)
dotnet publish -c Release -r linux-arm64 --self-contained true -o ./out

Then run:

./out/dtop          # Linux / macOS
out\dtop.exe        # Windows

---

Keyboard Controls

Sorting

Press a sort key once to sort by that column descending. Press it again to flip to ascending. The active column shows a ▼ or ▲ arrow.

Key	Sort by
C	CPU %
M	Memory (MB)
I	PID
E	Process name
H	Thread count
S	Status
A	Force ascending
D	Force descending
↑ / ↓	Toggle sort direction

Actions

Key	Action
P	Pause / resume live updates
N	Toggle all notifications on/off
G	Toggle Growl notifications on/off
L	Toggle email notifications on/off
T	Send a test notification on all enabled channels
R	Reload dtop.json from disk (no restart needed)
Q	Quit

---

Configuration

DTOP looks for dtop.json in these locations, in order:

1. Same directory as the executable (AppContext.BaseDirectory/dtop.json)
2. Home directory (~/.dtop.json)
3. Current working directory (./dtop.json)

The first file found wins. If no file is found, built-in defaults are used.

Full reference: dtop.json

{
  // How often to refresh process data (milliseconds)
  "refreshIntervalMs": 1000,

  // Maximum number of process rows shown on screen
  "maxProcessRows": 40,

  // Alert threshold: average CPU % across all cores
  "cpuHighThreshold": 80.0,

  // Alert threshold: used memory as % of total RAM
  "memoryHighThresholdPercent": 80.0,

  // Minimum seconds between OS-level (desktop) notifications of the same type
  "notificationCooldownSeconds": 30,

  // ── Growl (GNTP) ──────────────────────────────────────────────────────────
  "growl": {
    // Set to true to enable Growl alerts
    "enabled": false,

    // Growl host — use "localhost" if Growl is on the same machine
    "host": "localhost",

    // Growl GNTP port (default 23053)
    "port": 23053,

    // Growl password (leave empty if not set in Growl preferences)
    "password": "",

    // App name shown in Growl
    "appName": "DTOP",

    // Minimum seconds between Growl alerts of the same type (CPU / Memory)
    "cooldownSeconds": 60
  },

  // ── Email (SMTP) ──────────────────────────────────────────────────────────
  "email": {
    // Set to true to enable email alerts
    "enabled": false,

    // SMTP server hostname
    "smtpHost": "smtp.gmail.com",

    // SMTP port (587 = STARTTLS, 465 = SSL, 25 = plain)
    "smtpPort": 587,

    // Use SSL/TLS
    "useSsl": true,

    // SMTP login username
    "username": "your@gmail.com",

    // SMTP password or app-specific password (Gmail: use App Passwords)
    "password": "your-app-password",

    // From address (defaults to username if blank)
    "from": "your@gmail.com",

    // Recipient address (supports a single address)
    "to": "alert@example.com",

    // Minimum seconds between emails of the same alert type
    // (prevents repeated emails during a sustained high-CPU period)
    "cooldownSeconds": 300,

    // Hard cap: maximum emails sent per hour across all alert types
    "maxPerHour": 6
  },

  // ── Color thresholds ──────────────────────────────────────────────────────
  // Each entry maps a minimum value to a hex color.
  // The highest matching threshold wins.
  // Supported colors: #FF0000 #FF8800 #FFA500 #FFFF00 #00FF00
  //                   #008000 #00FFFF #008080 #0000FF #000080 #FFFFFF

  "cpuThresholds": [
    { "threshold": 0,  "color": "#FFFFFF" },
    { "threshold": 20, "color": "#FFFF00" },
    { "threshold": 50, "color": "#FF8800" },
    { "threshold": 80, "color": "#FF0000" }
  ],

  "memoryThresholds": [
    { "threshold": 0,  "color": "#FFFFFF" },
    { "threshold": 30, "color": "#00FFFF" },
    { "threshold": 60, "color": "#FF8800" },
    { "threshold": 85, "color": "#FF0000" }
  ]
}

Gmail setup

Gmail requires an App Password when 2FA is enabled (standard passwords are rejected).

1. Go to myaccount.google.com/apppasswords
2. Create a new app password (name it "DTOP")
3. Paste the 16-character password into dtop.json → email.password

Growl setup

Why no Growl.Connector NuGet package?

The official Growl.Connector NuGet package targets .NET Framework 4.0 only. It is not compatible with .NET 8. Adding it will produce:

error NU1202: Package Growl.Connector is not compatible with
net8.0 (.NETCoreApp,Version=v8.0)

DTOP instead uses its own raw GNTP/1.0 TCP implementation built into GrowlNotifier.cs. No NuGet install is needed — it works out of the box.

Setup steps

1. Install Growl for Windows or Growl for macOS
2. Open Growl preferences → Security → confirm GNTP is enabled on port 23053
3. Set growl.enabled: true in dtop.json
4. If you set a Growl password, add it to growl.password
5. Run DTOP and press T to send a test notification

Icon support

Place dtop.png next to the executable (same folder as dtop.json). The .csproj copies it to the build output automatically during dotnet build. The icon is read at startup, embedded as binary in the GNTP REGISTER message, and shown in Growl for every notification type.

If dtop.png is not found, notifications still work — just without an icon.

---

Notification Channels

DTOP supports three independent notification channels. Each has its own enable flag and cooldown so they don't interfere with each other.

Channel	Toggle key	Config section	Cooldown key
OS desktop	N	notificationCooldownSeconds (top-level)	per-type
Growl (GNTP)	G	growl	growl.cooldownSeconds
Email (SMTP)	L	email	email.cooldownSeconds + maxPerHour

Alert types: CPU (fired when average CPU across all cores exceeds cpuHighThreshold) and Memory (fired when used RAM exceeds memoryHighThresholdPercent).

Each type has its own cooldown timer, so a CPU alert won't reset the memory alert timer and vice versa.

---

Project Structure

DotnetHtop/
├── DotnetHtop.csproj       Project file — .NET 8, cross-platform
├── Program.cs              Entry point, AppState, display loop, keyboard thread,
│                           sort logic, alert dispatch
├── Config.cs               JSON config model (GrowlConfig, EmailConfig,
│                           ColorMapping) + file loader
├── ProcessInfo.cs          ProcessSnapshot record, ProcessCollector:
│                           Snapshot() + Compute() with correct CPU delta math
├── Renderer.cs             Diff-based terminal renderer — builds frames into a
│                           StringBuilder, only writes changed lines per frame
├── NotificationService.cs  Orchestrates OS + Growl + Email channels
├── GrowlNotifier.cs        Raw GNTP/1.0 over TCP — no NuGet dependency
├── EmailNotifier.cs        SMTP email with per-type cooldown + hourly cap
├── SystemInfo.cs           Cross-platform RAM detection and OS summary
├── ColorConsole.cs         Fallback colored console helpers (used pre-render)
├── StringExtensions.cs     Truncate() string helper
└── dtop.json               Full example config with all options documented

---

How the renderer works

Most terminal monitors flicker because they redraw the entire screen every frame (Console.Clear() or writing every line). DTOP uses a diff renderer:

1. Each frame, all lines are built into a (plain, ansi) pair list. The plain string is the change-detection key (no ANSI codes).
2. Each line is compared against the previous frame's plain text.
3. Only lines that changed are written to stdout, using absolute cursor positioning (\x1b[{row};1H) so only those rows update.
4. The entire output for a frame is assembled into one StringBuilder and sent in a single Console.Write() call — the terminal receives the whole diff atomically.

In a typical idle frame, fewer than 5 lines change out of 50+, so the terminal does almost no work — which is why it looks smooth.

---

CPU % calculation

The original code used elapsed / 10.0 which produces meaningless numbers. The correct formula is:

cpuPercent = (cpuTimeDelta.TotalMilliseconds / (elapsedMs × coreCount)) × 100

• cpuTimeDelta — difference in TotalProcessorTime between two snapshots
• elapsedMs — actual wall-clock milliseconds between the two snapshots (measured with Stopwatch, not assumed from Thread.Sleep)
• coreCount — Environment.ProcessorCount (logical cores)

This gives 0–100% per process regardless of how many cores the machine has.

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Platform notes

Feature	Windows	macOS	Linux
Process CPU/mem	✅	✅	✅
Total RAM detection	GCMemoryInfo → WMI	GCMemoryInfo → sysctl	GCMemoryInfo → /proc/meminfo
ANSI colors	Win10+ (ENABLE_VIRTUAL_TERMINAL_PROCESSING)	✅	✅
OS desktop notif	PowerShell toast	osascript	notify-send
Growl	✅ (GNTP TCP)	✅ (GNTP TCP)	✅ (GNTP TCP)
Email	✅	✅	✅

On Windows, ANSI escape processing is enabled automatically at startup via SetConsoleMode with ENABLE_VIRTUAL_TERMINAL_PROCESSING. This works on Windows 10 build 1607+ and Windows 11. Older Windows versions will fall back to plain output without color.

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Troubleshooting

Block characters (█ ░) show as ? or boxes Your terminal is not using UTF-8. Set chcp 65001 in cmd.exe before running, or switch to Windows Terminal which uses UTF-8 by default.

Colors not showing on Windows cmd.exe Run in Windows Terminal or PowerShell 7 instead. Legacy cmd.exe on older Windows versions does not support ANSI escape codes.

Growl test notification not arriving Check that Growl is running and GNTP is enabled in Growl preferences. Check that growl.port matches (default 23053). If Growl is on a remote machine, make sure the firewall allows inbound TCP on that port.

Email not sending Check SMTP credentials. For Gmail, use an App Password (not your account password). Check that smtpPort and useSsl match your provider. Errors are written to stderr — run dotnet run 2> errors.txt to capture them.

High CPU usage from DTOP itself Increase refreshIntervalMs (e.g. 2000 for 2-second refresh). The process list collection involves two snapshots 1 second apart by default.

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License

MIT — do whatever you want with it.

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👤 Author

Hadi Cahyadi

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