Replace CPU frequency with C-state monitoring

- Changed CpuData.frequency_mhz to CpuData.cstate (String)
- Implemented collect_cstate() to read CPU idle depth from sysfs
- Finds deepest C-state with most accumulated time (C0-C10)
- Updated dashboard to display C-state instead of frequency
- More accurate indicator of CPU activity vs power management

Bump version to v0.1.208

Co-Authored-By: Claude <noreply@anthropic.com>

Cargo.lock

@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.206"
+version = "0.1.207"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -324,7 +324,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.206"
+version = "0.1.207"
 dependencies = [
  "chrono",
  "serde",

agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-agent"
-version = "0.1.207"
+version = "0.1.208"
 edition = "2021"
 
 [dependencies]

agent/src/collectors/cpu.rs

@@ -119,36 +119,40 @@ impl CpuCollector {
         utils::parse_u64(content.trim())
     }
 
-    /// Collect CPU frequency and populate AgentData
-    async fn collect_frequency(&self, agent_data: &mut AgentData) -> Result<(), CollectorError> {
-        // Try scaling frequency first (more accurate for current frequency)
-        if let Ok(freq) =
-            utils::read_proc_file("/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq")
-        {
-            if let Ok(freq_khz) = utils::parse_u64(freq.trim()) {
-                let freq_mhz = freq_khz as f32 / 1000.0;
-                agent_data.system.cpu.frequency_mhz = freq_mhz;
-                return Ok(());
-            }
-        }
+    /// Collect CPU C-state (idle depth) and populate AgentData
+    async fn collect_cstate(&self, agent_data: &mut AgentData) -> Result<(), CollectorError> {
+        // Read C-state usage from first CPU (representative of overall system)
+        // C-states indicate CPU idle depth: C1=light sleep, C6=deep sleep, C10=deepest
 
-        // Fallback: parse /proc/cpuinfo for base frequency
-        if let Ok(content) = utils::read_proc_file("/proc/cpuinfo") {
-            for line in content.lines() {
-                if line.starts_with("cpu MHz") {
-                    if let Some(freq_str) = line.split(':').nth(1) {
-                        if let Ok(freq_mhz) = utils::parse_f32(freq_str) {
-                            agent_data.system.cpu.frequency_mhz = freq_mhz;
-                            return Ok(());
+        let mut deepest_state = String::from("C0"); // Default to active
+        let mut max_time: u64 = 0;
+
+        // Check C-states from CPU0
+        for state_num in 0..=10 {
+            let time_path = format!("/sys/devices/system/cpu/cpu0/cpuidle/state{}/time", state_num);
+            let name_path = format!("/sys/devices/system/cpu/cpu0/cpuidle/state{}/name", state_num);
+
+            if let Ok(time_str) = utils::read_proc_file(&time_path) {
+                if let Ok(time) = utils::parse_u64(time_str.trim()) {
+                    if time > max_time {
+                        // This state has most accumulated time
+                        if let Ok(name) = utils::read_proc_file(&name_path) {
+                            let state_name = name.trim().to_string();
+                            // Skip POLL state (not real idle)
+                            if state_name != "POLL" {
+                                max_time = time;
+                                deepest_state = state_name;
+                            }
                         }
                     }
-                    break; // Only need first CPU entry
                 }
+            } else {
+                // No more states available
+                break;
             }
         }
 
-        debug!("CPU frequency not available");
-        // Leave frequency as 0.0 if not available
+        agent_data.system.cpu.cstate = deepest_state;
         Ok(())
     }
 }
@@ -165,8 +169,8 @@ impl Collector for CpuCollector {
         // Collect temperature (optional)
         self.collect_temperature(agent_data).await?;
 
-        // Collect frequency (optional)
-        self.collect_frequency(agent_data).await?;
+        // Collect C-state (CPU idle depth)
+        self.collect_cstate(agent_data).await?;
 
         let duration = start.elapsed();
         debug!("CPU collection completed in {:?}", duration);

dashboard/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard"
-version = "0.1.206"
+version = "0.1.208"
 edition = "2021"
 
 [dependencies]

dashboard/src/ui/widgets/system.rs

@@ -26,7 +26,7 @@ pub struct SystemWidget {
     cpu_load_1min: Option<f32>,
     cpu_load_5min: Option<f32>,
     cpu_load_15min: Option<f32>,
-    cpu_frequency: Option<f32>,
+    cpu_cstate: Option<String>,
     cpu_status: Status,
     
     // Memory metrics
@@ -102,7 +102,7 @@ impl SystemWidget {
             cpu_load_1min: None,
             cpu_load_5min: None,
             cpu_load_15min: None,
-            cpu_frequency: None,
+            cpu_cstate: None,
             cpu_status: Status::Unknown,
             memory_usage_percent: None,
             memory_used_gb: None,
@@ -137,11 +137,11 @@ impl SystemWidget {
         }
     }
 
-    /// Format CPU frequency
-    fn format_cpu_frequency(&self) -> String {
-        match self.cpu_frequency {
-            Some(freq) => format!("{:.0} MHz", freq),
-            None => "— MHz".to_string(),
+    /// Format CPU C-state (idle depth)
+    fn format_cpu_cstate(&self) -> String {
+        match &self.cpu_cstate {
+            Some(cstate) => cstate.clone(),
+            None => "—".to_string(),
         }
     }
 
@@ -188,7 +188,7 @@ impl Widget for SystemWidget {
         self.cpu_load_1min = Some(cpu.load_1min);
         self.cpu_load_5min = Some(cpu.load_5min);
         self.cpu_load_15min = Some(cpu.load_15min);
-        self.cpu_frequency = Some(cpu.frequency_mhz);
+        self.cpu_cstate = Some(cpu.cstate.clone());
         self.cpu_status = Status::Ok;
 
         // Extract memory data directly
@@ -832,10 +832,10 @@ impl SystemWidget {
         );
         lines.push(Line::from(cpu_spans));
 
-        let freq_text = self.format_cpu_frequency();
+        let cstate_text = self.format_cpu_cstate();
         lines.push(Line::from(vec![
             Span::styled("  └─ ", Typography::tree()),
-            Span::styled(format!("Freq: {}", freq_text), Typography::secondary())
+            Span::styled(format!("C-state: {}", cstate_text), Typography::secondary())
         ]));
 
         // RAM section

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.207"
+version = "0.1.208"
 edition = "2021"
 
 [dependencies]

shared/src/agent_data.rs

@@ -46,7 +46,7 @@ pub struct CpuData {
     pub load_1min: f32,
     pub load_5min: f32,
     pub load_15min: f32,
-    pub frequency_mhz: f32,
+    pub cstate: String, // Deepest C-state in use (C1, C6, C10, etc.) - indicates CPU idle depth
     pub temperature_celsius: Option<f32>,
     pub load_status: Status,
     pub temperature_status: Status,
@@ -204,7 +204,7 @@ impl AgentData {
                     load_1min: 0.0,
                     load_5min: 0.0,
                     load_15min: 0.0,
-                    frequency_mhz: 0.0,
+                    cstate: String::from("C0"),
                     temperature_celsius: None,
                     load_status: Status::Unknown,
                     temperature_status: Status::Unknown,