multiple feature and performance improvements (see description)

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Release notes — 2025-08-12

Highlights

Agent back to near-zero CPU when idle (request-driven, no background samplers).
Accurate per-process CPU% via /proc deltas; only top-level processes (threads hidden).
TUI: processes pane gets scrollbar, click-to-sort (CPU% or Mem) with indicator, stable total count.
Network panes made taller; disks slightly reduced.
README revamped: rustup prereqs, crates.io install, update/systemd instructions.
Clippy cleanups across agent and client.
Agent

Reverted precompressed caches and background samplers; WebSocket path is request-driven again.
Ensured on-demand gzip for larger replies; no per-request overhead when small.
Processes: switched to refresh_processes_specifics with ProcessRefreshKind::everything().without_tasks() to exclude threads.
Per-process CPU% now computed from /proc jiffies deltas using a small ProcCpuTracker (fixes “always 0%”/scaling issues).
Optional metrics and light caching:
CPU temp and GPU metrics gated by env (SOCKTOP_AGENT_TEMP=0, SOCKTOP_AGENT_GPU=0).
Tiny TTL caches via once_cell to avoid rescanning sensors every tick.
Dependencies: added once_cell = "1.19".
No API changes to WS endpoints.
Client (TUI)

Processes pane:
Scrollbar (mouse wheel, drag; keyboard arrows/PageUp/PageDown/Home/End).
Click header to sort by CPU% or Mem; dot indicator on active column.
Preserves process_count across fast metrics updates to avoid flicker.
UI/theme:
Shared scrollbar colors moved to ui/theme.rs; both CPU and Processes reuse them.
Cached pane rect to fix input handling; removed unused vars.
Layout: network download/upload get more vertical space; disks shrink slightly.
Clippy fixes: derive Default for ProcSortBy; style/import cleanups.
Docs

README: added rustup install steps (with proper shell reload), install via cargo install socktop and cargo install socktop_agent, and a clear Updating section (systemd service steps included).
Features list updated; roadmap marks independent cadences as done.
Upgrade notes

Agent: cargo install socktop_agent --force, then restart your systemd service; if unit changed, systemctl daemon-reload.
TUI: cargo install socktop --force.
Optional envs to trim overhead: SOCKTOP_AGENT_GPU=0, SOCKTOP_AGENT_TEMP=0.
No config or API breaking changes.

socktop_agent/src/main.rs

@@ -9,64 +9,25 @@ mod types;
 mod ws;
 
 use axum::{routing::get, Router};
-use std::{net::SocketAddr, sync::atomic::AtomicUsize, sync::Arc, time::Duration};
+use std::net::SocketAddr;
 
-use sysinfo::{
-    Components, CpuRefreshKind, Disks, MemoryRefreshKind, Networks, ProcessRefreshKind,
-    RefreshKind, System,
-};
-use tokio::sync::{Mutex, Notify, RwLock};
-use tracing_subscriber::EnvFilter;
-
-use sampler::spawn_sampler;
+use crate::sampler::{spawn_disks_sampler, spawn_process_sampler, spawn_sampler};
 use state::AppState;
 use ws::ws_handler;
 
 #[tokio::main]
 async fn main() {
-    // Init logging; configure with RUST_LOG (e.g., RUST_LOG=info).
-    tracing_subscriber::fmt()
-        .with_env_filter(EnvFilter::from_default_env())
-        .with_target(false)
-        .compact()
-        .init();
+    tracing_subscriber::fmt::init();
 
-    // sysinfo build specifics (scopes what refresh_all() will touch internally)
-    let refresh_kind = RefreshKind::nothing()
-        .with_cpu(CpuRefreshKind::everything())
-        .with_memory(MemoryRefreshKind::everything())
-        .with_processes(ProcessRefreshKind::everything());
-
-    // Initialize sysinfo handles once and keep them alive
-    let mut sys = System::new_with_specifics(refresh_kind);
-    sys.refresh_all();
-
-    let mut nets = Networks::new();
-    nets.refresh(true);
-
-    let mut components = Components::new();
-    components.refresh(true);
-
-    let mut disks = Disks::new();
-    disks.refresh(true);
-
-    // Shared state across requests
-    let state = AppState {
-        sys: Arc::new(Mutex::new(sys)),
-        last_json: Arc::new(RwLock::new(String::new())),
-        components: Arc::new(Mutex::new(components)),
-        disks: Arc::new(Mutex::new(disks)),
-        networks: Arc::new(Mutex::new(nets)),
-        // new: adaptive sampling controls
-        client_count: Arc::new(AtomicUsize::new(0)),
-        wake_sampler: Arc::new(Notify::new()),
-        auth_token: std::env::var("SOCKTOP_TOKEN")
-            .ok()
-            .filter(|s| !s.is_empty()),
-    };
+    let state = AppState::new();
 
     // Start background sampler (adjust cadence as needed)
-    let _sampler = spawn_sampler(state.clone(), Duration::from_millis(500));
+    // 500ms fast metrics
+    let _h_fast = spawn_sampler(state.clone(), std::time::Duration::from_millis(500));
+    // 2s processes (top 50)
+    let _h_procs = spawn_process_sampler(state.clone(), std::time::Duration::from_secs(2), 50);
+    // 5s disks
+    let _h_disks = spawn_disks_sampler(state.clone(), std::time::Duration::from_secs(5));
 
     // Web app
     let port = resolve_port();