perf: merge cpuCoreUsage/cpuCoreFreq/cpuCoreHistory into single cpuCores array

modules/Cpu.qml

@@ -22,9 +22,7 @@ M.BarSection {
         }
     }
 
-    readonly property var _coreUsage: M.SystemStats.cpuCoreUsage
-    readonly property var _coreFreq: M.SystemStats.cpuCoreFreq
-    readonly property var _coreHistory: M.SystemStats.cpuCoreHistory
+    readonly property var _cores: M.SystemStats.cpuCores
     readonly property var _coreMaxFreq: M.SystemStats.cpuCoreMaxFreq
     readonly property var _coreTypes: M.SystemStats.cpuCoreTypes
 
@@ -114,14 +112,14 @@ M.BarSection {
 
         // Per-core rows
         Repeater {
-            model: root._coreUsage.length
+            model: root._cores.length
 
             delegate: Item {
                 required property int index
                 width: hoverPanel.contentWidth
 
-                readonly property int _u: root._coreUsage[index] ?? 0
-                readonly property real _f: root._coreFreq[index] ?? 0
+                readonly property int _u: root._cores[index]?.usage ?? 0
+                readonly property real _f: root._cores[index]?.freq_ghz ?? 0
                 readonly property color _barColor: root._loadColor(_u)
                 readonly property bool _throttled: {
                     const maxF = root._coreMaxFreq[index] ?? 0;
@@ -204,7 +202,7 @@ M.BarSection {
                         width: 32
                         height: 10
 
-                        property var _hist: root._coreHistory[parent.parent.index] || []
+                        property var _hist: root._cores[parent.parent.index]?.history ?? []
                         property color _col: parent.parent._barColor
 
                         on_HistChanged: if (root._showPanel)

modules/SystemStats.qml

@@ -10,9 +10,7 @@ QtObject {
     // ── CPU ──────────────────────────────────────────────────────────────
     property int cpuUsage: 0
     property real cpuFreqGhz: 0
-    property var cpuCoreUsage: []
-    property var cpuCoreFreq: []
-    property var cpuCoreHistory: []
+    property var cpuCores: []        // [{usage, freq_ghz, history:[]}]
     property var cpuCoreMaxFreq: []
     property var cpuCoreTypes: []
 
@@ -40,17 +38,17 @@ QtObject {
                     if (ev.type === "cpu") {
                         root.cpuUsage = ev.usage;
                         root.cpuFreqGhz = ev.freq_ghz;
-                        root.cpuCoreUsage = ev.core_usage;
-                        root.cpuCoreFreq = ev.core_freq_ghz;
                         const histLen = 16;
-                        const oldH = root.cpuCoreHistory;
-                        const newH = [];
-                        for (let i = 0; i < ev.core_usage.length; i++) {
-                            const prev = i < oldH.length ? oldH[i] : [];
-                            const next = prev.concat([ev.core_usage[i]]);
-                            newH.push(next.length > histLen ? next.slice(next.length - histLen) : next);
-                        }
-                        root.cpuCoreHistory = newH;
+                        const prev = root.cpuCores;
+                        root.cpuCores = ev.cores.map((c, i) => {
+                            const oldHist = prev[i]?.history ?? [];
+                            const hist = oldHist.concat([c.usage]);
+                            return {
+                                usage: c.usage,
+                                freq_ghz: c.freq_ghz,
+                                history: hist.length > histLen ? hist.slice(hist.length - histLen) : hist
+                            };
+                        });
                     } else if (ev.type === "mem") {
                         root.memPercent = ev.percent;
                         root.memUsedGb = ev.used_gb;

stats-daemon/src/main.rs

@@ -132,22 +132,18 @@ fn emit_cpu(out: &mut impl Write, prev: &[Sample], curr: &[Sample], freqs: &[f64
         freqs.iter().sum::<f64>() / freqs.len() as f64
     };
 
+    let n = core_usage.len().max(freqs.len());
     let _ = write!(
         out,
-        "{{\"type\":\"cpu\",\"usage\":{usage},\"freq_ghz\":{avg_freq:.3},\"core_usage\":["
+        "{{\"type\":\"cpu\",\"usage\":{usage},\"freq_ghz\":{avg_freq:.3},\"cores\":["
     );
-    for (i, u) in core_usage.iter().enumerate() {
+    for i in 0..n {
         if i > 0 {
             let _ = write!(out, ",");
         }
-        let _ = write!(out, "{u}");
-    }
-    let _ = write!(out, "],\"core_freq_ghz\":[");
-    for (i, f) in freqs.iter().enumerate() {
-        if i > 0 {
-            let _ = write!(out, ",");
-        }
-        let _ = write!(out, "{f:.3}");
+        let u = core_usage.get(i).copied().unwrap_or(0);
+        let f = freqs.get(i).copied().unwrap_or(0.0);
+        let _ = write!(out, "{{\"usage\":{u},\"freq_ghz\":{f:.3}}}");
     }
     let _ = writeln!(out, "]}}");
 }
@@ -360,8 +356,7 @@ SwapFree:        8192000 kB";
         assert!(s.contains("\"type\":\"cpu\""));
         assert!(s.contains("\"usage\":"));
         assert!(s.contains("\"freq_ghz\":"));
-        assert!(s.contains("\"core_usage\":"));
-        assert!(s.contains("\"core_freq_ghz\":"));
+        assert!(s.contains("\"cores\":"));
         assert!(s.trim().ends_with('}'));
     }
 
@@ -399,8 +394,8 @@ SwapFree:        8192000 kB";
         let mut buf = Vec::new();
         emit_cpu(&mut buf, &curr, &curr, &freqs);
         let s = String::from_utf8(buf).unwrap();
-        assert!(s.contains("3.200"), "got: {s}");
-        assert!(s.contains("2.900"), "got: {s}");
+        assert!(s.contains("\"freq_ghz\":3.200"), "got: {s}");
+        assert!(s.contains("\"freq_ghz\":2.900"), "got: {s}");
     }
 
     // ── emit_mem (via parse_meminfo) ─────────────────────────────────────