added commentation

WatcherAgent/src/hardware/gpu.rs

@@ -2,6 +2,29 @@ use anyhow::Result;
 use nvml_wrapper::Nvml;
 use std::error::Error;
 
+//! # GPU Hardware Module
+//!
+//! This module provides GPU information collection for WatcherAgent, including load, temperature, and VRAM statistics.
+//!
+//! ## Responsibilities
+//! - **GPU Detection:** Identifies GPU model and capabilities.
+//! - **Metric Collection:** Queries GPU load, temperature, and VRAM usage using NVML (NVIDIA only).
+//! - **Error Handling:** Graceful fallback if GPU or NVML is unavailable.
+//!
+//! ## Units
+//! - `current_load`: GPU usage as a percentage (**0.0–100.0**)
+//! - `current_temp`: GPU temperature in **degrees Celsius (°C)**
+//! - `vram_total`: Total VRAM in **megabytes (MB)**
+//! - `vram_used`: Used VRAM in **megabytes (MB)**
+//!
+/// GPU statistics for the host system.
+///
+/// # Fields
+/// - `name`: GPU model name (string)
+/// - `current_load`: GPU usage as a percentage (**0.0–100.0**)
+/// - `current_temp`: GPU temperature in **degrees Celsius (°C)**
+/// - `vram_total`: Total VRAM in **megabytes (MB)**
+/// - `vram_used`: Used VRAM in **megabytes (MB)**
 #[derive(Debug)]
 pub struct GpuInfo {
     pub name: Option<String>,
@@ -11,6 +34,12 @@ pub struct GpuInfo {
     pub vram_used: Option<f64>,
 }
 
+/// Collects GPU information (load, temperature, VRAM) using NVML.
+///
+/// This function attempts to query the first NVIDIA GPU using NVML. If unavailable, it returns a fallback with only the detected GPU name.
+///
+/// # Returns
+/// * `Result<GpuInfo, Box<dyn Error + Send + Sync>>` - GPU statistics or fallback if unavailable.
 pub async fn get_gpu_info() -> Result<GpuInfo, Box<dyn Error + Send + Sync>> {
     match get_gpu_metrics() {
         Ok((gpu_temp, gpu_load, vram_used, vram_total)) => {
@@ -37,6 +66,10 @@ pub async fn get_gpu_info() -> Result<GpuInfo, Box<dyn Error + Send + Sync>> {
     }
 }
 
+/// Queries NVML for GPU metrics: temperature, load, VRAM used/total.
+///
+/// # Returns
+/// * `Result<(f64, f64, f64, f64), Box<dyn Error + Send + Sync>>` - Tuple of (temperature °C, load %, VRAM used MB, VRAM total MB).
 pub fn get_gpu_metrics() -> Result<(f64, f64, f64, f64), Box<dyn Error + Send + Sync>> {
     let nvml = Nvml::init();
     if let Ok(nvml) = nvml {