Reduce CPU usage with conditional rendering

Implement event-driven rendering to dramatically reduce CPU usage.
Only render when something actually changes instead of constantly
rendering at 20 FPS.

Changes:
- Increase poll timeout from 50ms to 200ms (5 FPS)
- Add needs_render flag to track when rendering is required
- Trigger rendering only on: user input, new metrics, heartbeat
  checks, or terminal resize events
- Reset render flag after each render cycle

Based on cm-player optimization approach.

Cargo.lock

@@ -279,7 +279,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.260"
+version = "0.1.265"
 dependencies = [
  "anyhow",
  "chrono",
@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.260"
+version = "0.1.265"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -325,7 +325,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.260"
+version = "0.1.265"
 dependencies = [
  "chrono",
  "serde",

agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-agent"
-version = "0.1.261"
+version = "0.1.266"
 edition = "2021"
 
 [dependencies]

agent/src/collectors/systemd.rs

@@ -217,14 +217,15 @@ impl SystemdCollector {
                     }
 
                     if service_name == "tailscaled" && status_info.active_state == "active" {
-                        // Add Tailscale connection method as sub-service
-                        if let Some(conn_method) = self.get_tailscale_connection_method() {
+                        // Add Tailscale peers with their connection methods as sub-services
+                        let peers = self.get_tailscale_peers();
+                        for (peer_name, conn_method) in peers {
                             let metrics = Vec::new();
                             sub_services.push(SubServiceData {
-                                name: format!("Connection: {}", conn_method),
+                                name: format!("{}: {}", peer_name, conn_method),
                                 service_status: Status::Info,
                                 metrics,
-                                service_type: "tailscale_connection".to_string(),
+                                service_type: "tailscale_peer".to_string(),
                             });
                         }
                     }
@@ -936,50 +937,77 @@ impl SystemdCollector {
         None
     }
 
-    /// Get Tailscale connection method (direct, relay, or proxy)
-    fn get_tailscale_connection_method(&self) -> Option<String> {
+    /// Get Tailscale connected peers with their connection methods
+    /// Returns a list of (device_name, connection_method) tuples
+    fn get_tailscale_peers(&self) -> Vec<(String, String)> {
         match Command::new("timeout")
-            .args(["2", "tailscale", "status", "--json"])
+            .args(["2", "tailscale", "status"])
             .output()
         {
             Ok(output) if output.status.success() => {
-                let json_str = String::from_utf8_lossy(&output.stdout);
+                let status_output = String::from_utf8_lossy(&output.stdout);
+                let mut peers = Vec::new();
 
-                if let Ok(json_data) = serde_json::from_str::<serde_json::Value>(&json_str) {
-                    // Look for the self peer (current node) in the peer list
-                    if let Some(peers) = json_data["Peer"].as_object() {
-                        // Find the first active peer connection to determine connection method
-                        for (_peer_id, peer_data) in peers {
-                            if peer_data["Active"].as_bool().unwrap_or(false) {
-                                // Check if using relay
-                                let relay_node = peer_data["Relay"].as_str().unwrap_or("");
-                                if !relay_node.is_empty() {
-                                    return Some("relay".to_string());
-                                }
+                // Get current hostname to filter it out
+                let current_hostname = gethostname::gethostname()
+                    .to_string_lossy()
+                    .to_string();
 
-                                // Check if using direct connection
-                                if let Some(endpoints) = peer_data["CurAddr"].as_str() {
-                                    if !endpoints.is_empty() {
-                                        return Some("direct".to_string());
-                                    }
-                                }
-                            }
-                        }
+                // Parse tailscale status output
+                // Format: IP  hostname  user  os  status
+                // Example: 100.110.98.3    wslbox               cm@          linux   active; direct 192.168.30.227:53757
+                // Note: First line is always the current host, skip it
+                for (idx, line) in status_output.lines().enumerate() {
+                    if idx == 0 {
+                        continue; // Skip first line (current host)
                     }
 
-                    // Check if using proxy from backend state
-                    if let Some(backend_state) = json_data["BackendState"].as_str() {
-                        if backend_state == "Running" {
-                            // If we're running but have no direct or relay, might be proxy
-                            // This is a fallback heuristic
-                            return Some("unknown".to_string());
-                        }
+                    let parts: Vec<&str> = line.split_whitespace().collect();
+                    if parts.len() < 5 {
+                        continue; // Skip invalid lines
                     }
+
+                    // parts[0] = IP
+                    // parts[1] = hostname
+                    // parts[2] = user
+                    // parts[3] = OS
+                    // parts[4+] = status (e.g., "active;", "direct", "192.168.30.227:53757" or "idle;" or "offline")
+
+                    let hostname = parts[1];
+
+                    // Skip if this is the current host (double-check in case format changes)
+                    if hostname == current_hostname {
+                        continue;
+                    }
+
+                    let status_parts = &parts[4..];
+
+                    // Determine connection method from status
+                    let connection_method = if status_parts.is_empty() {
+                        continue; // Skip if no status
+                    } else {
+                        let status_str = status_parts.join(" ");
+                        if status_str.contains("offline") {
+                            continue; // Skip offline peers
+                        } else if status_str.contains("direct") {
+                            "direct"
+                        } else if status_str.contains("relay") {
+                            "relay"
+                        } else if status_str.contains("idle") {
+                            "idle"
+                        } else if status_str.contains("active") {
+                            "active"
+                        } else {
+                            continue; // Skip unknown status
+                        }
+                    };
+
+                    peers.push((hostname.to_string(), connection_method.to_string()));
                 }
 
-                None
+                peers
             }
-            _ => None,
+            _ => Vec::new(),
         }
     }
 

dashboard/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard"
-version = "0.1.261"
+version = "0.1.266"
 edition = "2021"
 
 [dependencies]

dashboard/src/app.rs

@@ -138,11 +138,12 @@ impl Dashboard {
         let metrics_check_interval = Duration::from_millis(100); // Check for metrics every 100ms
         let mut last_heartbeat_check = Instant::now();
         let heartbeat_check_interval = Duration::from_secs(1); // Check for host connectivity every 1 second
+        let mut needs_render = true; // Track if we need to render
 
         loop {
             // Handle terminal events (keyboard and mouse input) only if not headless
             if !self.headless {
-                match event::poll(Duration::from_millis(50)) {
+                match event::poll(Duration::from_millis(200)) {
                     Ok(true) => {
                         match event::read() {
                             Ok(event) => {
@@ -152,6 +153,7 @@ impl Dashboard {
                                             // Handle keyboard input
                                             match tui_app.handle_input(event) {
                                                 Ok(_) => {
+                                                    needs_render = true;
                                                     // Check if we should quit
                                                     if tui_app.should_quit() {
                                                         info!("Quit requested, exiting dashboard");
@@ -168,10 +170,11 @@ impl Dashboard {
                                             if let Err(e) = self.handle_mouse_event(mouse_event) {
                                                 error!("Error handling mouse event: {}", e);
                                             }
+                                            needs_render = true;
                                         }
                                         Event::Resize(_width, _height) => {
-                                            // Terminal was resized - just continue and re-render
-                                            // The next render will automatically use the new size
+                                            // Terminal was resized - mark for re-render
+                                            needs_render = true;
                                         }
                                         _ => {}
                                     }
@@ -189,38 +192,6 @@ impl Dashboard {
                         break;
                     }
                 }
-
-                // Render UI immediately after handling input for responsive feedback
-                if let Some(ref mut terminal) = self.terminal {
-                    if let Some(ref mut tui_app) = self.tui_app {
-                        // Clear and autoresize terminal to handle any resize events
-                        if let Err(e) = terminal.autoresize() {
-                            warn!("Error autoresizing terminal: {}", e);
-                        }
-
-                        // Check minimum terminal size to prevent panics
-                        let size = terminal.size().unwrap_or_default();
-                        if size.width < 90 || size.height < 15 {
-                            // Terminal too small, show error message
-                            let msg_text = format!("Terminal too small\n\nMinimum: 90x15\nCurrent: {}x{}", size.width, size.height);
-                            let _ = terminal.draw(|frame| {
-                                use ratatui::widgets::{Paragraph, Block, Borders};
-                                use ratatui::layout::Alignment;
-                                let msg = Paragraph::new(msg_text.clone())
-                                    .alignment(Alignment::Center)
-                                    .block(Block::default().borders(Borders::ALL));
-                                frame.render_widget(msg, frame.size());
-                            });
-                        } else if let Err(e) = terminal.draw(|frame| {
-                            let (title_area, system_area, services_area) = tui_app.render(frame, &self.metric_store);
-                            self.title_area = title_area;
-                            self.system_area = system_area;
-                            self.services_area = services_area;
-                        }) {
-                            error!("Error rendering TUI after input: {}", e);
-                        }
-                    }
-                }
             }
 
             // Check for new metrics
@@ -259,8 +230,10 @@ impl Dashboard {
                     if let Some(ref mut tui_app) = self.tui_app {
                         tui_app.update_metrics(&mut self.metric_store);
                     }
+
+                    needs_render = true; // New metrics received, need to render
                 }
-                
+
                 // Also check for command output messages
                 if let Ok(Some(cmd_output)) = self.zmq_consumer.receive_command_output().await {
                     debug!(
@@ -271,26 +244,27 @@ impl Dashboard {
 
                     // Command output (terminal popup removed - output not displayed)
                 }
-                
+
                 last_metrics_check = Instant::now();
             }
 
             // Check for host connectivity changes (heartbeat timeouts) periodically
             if last_heartbeat_check.elapsed() >= heartbeat_check_interval {
                 let timeout = Duration::from_secs(self.config.zmq.heartbeat_timeout_seconds);
-                
+
                 // Clean up metrics for offline hosts
                 self.metric_store.cleanup_offline_hosts(timeout);
-                
+
                 if let Some(ref mut tui_app) = self.tui_app {
                     let connected_hosts = self.metric_store.get_connected_hosts(timeout);
                     tui_app.update_hosts(connected_hosts);
                 }
                 last_heartbeat_check = Instant::now();
+                needs_render = true; // Heartbeat check happened, may have changed hosts
             }
 
-            // Render TUI (only if not headless)
-            if !self.headless {
+            // Render TUI only when needed (not headless and something changed)
+            if !self.headless && needs_render {
                 if let Some(ref mut terminal) = self.terminal {
                     if let Some(ref mut tui_app) = self.tui_app {
                         // Clear and autoresize terminal to handle any resize events
@@ -322,10 +296,8 @@ impl Dashboard {
                         }
                     }
                 }
+                needs_render = false; // Reset flag after rendering
             }
-
-            // Small sleep to prevent excessive CPU usage
-            tokio::time::sleep(Duration::from_millis(10)).await;
         }
 
         info!("Dashboard main loop ended");

dashboard/src/metrics/store.rs

@@ -86,16 +86,6 @@ impl MetricStore {
         self.current_agent_data.get(hostname)
     }
 
-    /// Get ZMQ communication statistics for a host
-    pub fn get_zmq_stats(&mut self, hostname: &str) -> Option<ZmqStats> {
-        let now = Instant::now();
-        self.zmq_stats.get_mut(hostname).map(|stats| {
-            // Update packet age
-            stats.last_packet_age_secs = now.duration_since(stats.last_packet_time).as_secs_f64();
-            stats.clone()
-        })
-    }
-
     /// Get connected hosts (hosts with recent heartbeats)
     pub fn get_connected_hosts(&self, timeout: Duration) -> Vec<String> {
         let now = Instant::now();

dashboard/src/ui/widgets/services.rs

@@ -102,7 +102,6 @@ pub struct ServicesWidget {
 struct ServiceInfo {
     metrics: Vec<(String, f32, Option<String>)>, // (label, value, unit)
     widget_status: Status,
-    service_type: String, // "nginx_site", "container", "image", or empty for parent services
     memory_bytes: Option<u64>,
     restart_count: Option<u32>,
     uptime_seconds: Option<u64>,
@@ -344,18 +343,86 @@ impl ServicesWidget {
     pub fn select_previous(&mut self) {
         if self.selected_index > 0 {
             self.selected_index -= 1;
+            self.ensure_selected_visible();
         }
         debug!("Service selection moved up to: {}", self.selected_index);
     }
 
-    /// Move selection down  
+    /// Move selection down
     pub fn select_next(&mut self, total_services: usize) {
         if total_services > 0 && self.selected_index < total_services.saturating_sub(1) {
             self.selected_index += 1;
+            self.ensure_selected_visible();
         }
         debug!("Service selection: {}/{}", self.selected_index, total_services);
     }
 
+    /// Convert parent service index to display line index
+    fn parent_index_to_display_line(&self, parent_index: usize) -> usize {
+        let mut parent_services: Vec<_> = self.parent_services.iter().collect();
+        parent_services.sort_by(|(a, _), (b, _)| a.cmp(b));
+
+        let mut display_line = 0;
+        for (idx, (parent_name, _)) in parent_services.iter().enumerate() {
+            if idx == parent_index {
+                return display_line;
+            }
+            display_line += 1; // Parent service line
+
+            // Add sub-service lines
+            if let Some(sub_list) = self.sub_services.get(*parent_name) {
+                display_line += sub_list.len();
+            }
+        }
+        display_line
+    }
+
+    /// Ensure the currently selected service is visible in the viewport
+    fn ensure_selected_visible(&mut self) {
+        if self.last_viewport_height == 0 {
+            return; // Can't adjust without knowing viewport size
+        }
+
+        let display_line = self.parent_index_to_display_line(self.selected_index);
+        let total_display_lines = self.get_total_display_lines();
+        let viewport_height = self.last_viewport_height;
+
+        // Check if selected line is above visible area
+        if display_line < self.scroll_offset {
+            self.scroll_offset = display_line;
+            return;
+        }
+
+        // Calculate current effective viewport (accounting for "more below" if present)
+        let current_remaining = total_display_lines.saturating_sub(self.scroll_offset);
+        let current_has_more = current_remaining > viewport_height;
+        let current_effective = if current_has_more {
+            viewport_height.saturating_sub(1)
+        } else {
+            viewport_height
+        };
+
+        // Check if selected line is below current visible area
+        if display_line >= self.scroll_offset + current_effective {
+            // Need to scroll down. Position selected line so there's room for "more below" if needed
+            // Strategy: if there are lines below the selected line, don't put it at the very bottom
+            let has_content_below = display_line < total_display_lines - 1;
+
+            if has_content_below {
+                // Leave room for "... X more below" message by positioning selected line
+                // one position higher than the last line
+                let target_position = viewport_height.saturating_sub(2);
+                self.scroll_offset = display_line.saturating_sub(target_position);
+            } else {
+                // This is the last line, can put it at the bottom
+                self.scroll_offset = display_line.saturating_sub(viewport_height - 1);
+            }
+        }
+
+        debug!("Auto-scroll: selected={}, display_line={}, scroll_offset={}, viewport={}, total={}",
+            self.selected_index, display_line, self.scroll_offset, viewport_height, total_display_lines);
+    }
+
     /// Get currently selected service name (for actions)
     /// Only returns parent service names since only parent services can be selected
     pub fn get_selected_service(&self) -> Option<String> {
@@ -488,7 +555,6 @@ impl Widget for ServicesWidget {
             let parent_info = ServiceInfo {
                 metrics: Vec::new(), // Parent services don't have custom metrics
                 widget_status: service.service_status,
-                service_type: String::new(), // Parent services have no type
                 memory_bytes: service.memory_bytes,
                 restart_count: service.restart_count,
                 uptime_seconds: service.uptime_seconds,
@@ -507,7 +573,6 @@ impl Widget for ServicesWidget {
                     let sub_info = ServiceInfo {
                         metrics,
                         widget_status: sub_service.service_status,
-                        service_type: sub_service.service_type.clone(),
                         memory_bytes: None, // Sub-services don't have individual metrics yet
                         restart_count: None,
                         uptime_seconds: None,
@@ -552,7 +617,6 @@ impl ServicesWidget {
                                 .or_insert(ServiceInfo {
                                     metrics: Vec::new(),
                                     widget_status: Status::Unknown,
-                                    service_type: String::new(),
                                     memory_bytes: None,
                                     restart_count: None,
                                     uptime_seconds: None,
@@ -581,7 +645,6 @@ impl ServicesWidget {
                                 ServiceInfo {
                                     metrics: Vec::new(),
                                     widget_status: Status::Unknown,
-                                    service_type: String::new(), // Unknown type in legacy path
                                     memory_bytes: None,
                                     restart_count: None,
                                     uptime_seconds: None,

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.261"
+version = "0.1.266"
 edition = "2021"
 
 [dependencies]