perf: report top-5 processes by CPU and memory

Collect every named process per sample, then send the top-5 by CPU and the
top-5 by memory as a `top_processes` object alongside the existing single
top-CPU/top-memory scalars (kept for backward compatibility). opsbase shows
these as 5-row lists in the device's Live performance card.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/perf.rs

@@ -57,6 +57,9 @@ struct PendingSample {
     top_cpu_pct: f64,
     top_mem_name: String,
     top_mem_mb: i64,
+    /// Top-5 processes by CPU (name, normalised %) and by memory (name, MB).
+    top_cpu_procs: Vec<(String, f64)>,
+    top_mem_procs: Vec<(String, i64)>,
     attempts: u32,
 }
 
@@ -156,33 +159,48 @@ fn collect_sample(sys: &mut hbb_common::sysinfo::System) -> Option<PendingSample
     // CPU% reading (both 0-100 of the whole machine).
     let cpu_count = sys.cpus().len().max(1) as f64;
 
-    let mut top_cpu: Option<(&str, f32)> = None;
-    let mut top_mem: Option<(&str, u64)> = None;
+    // Collect every (named) process once, then derive the top-5 by CPU and by
+    // memory. The single top_cpu_*/top_mem_* scalars are kept for backward
+    // compatibility (older servers ignore top_processes).
+    let mut procs: Vec<(&str, f64, i64)> = Vec::new();
     let mut proc_count = 0i64;
     for proc in sys.processes().values() {
         proc_count += 1;
         let name = proc.name();
         // Some kernel-side rows show up with empty names on Windows;
-        // skip them so we don't ever render a top-CPU row with no
-        // label.
+        // skip them so we don't ever render a top row with no label.
         if name.is_empty() {
             continue;
         }
         let cu = proc.cpu_usage();
-        if cu.is_finite() && cu > top_cpu.map(|(_, v)| v).unwrap_or(0.0) {
-            top_cpu = Some((name, cu));
-        }
-        let mu = proc.memory();
-        if mu > top_mem.map(|(_, v)| v).unwrap_or(0) {
-            top_mem = Some((name, mu));
-        }
+        let cu = if cu.is_finite() { (cu as f64 / cpu_count).min(100.0) } else { 0.0 };
+        let mb = (proc.memory() / 1024 / 1024) as i64;
+        procs.push((name, cu, mb));
     }
 
-    let (top_cpu_name, top_cpu_pct) = top_cpu
-        .map(|(n, v)| (n.to_string(), (v as f64 / cpu_count).min(100.0)))
+    let mut by_cpu = procs.clone();
+    by_cpu.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
+    let top_cpu_procs: Vec<(String, f64)> = by_cpu
+        .iter()
+        .take(5)
+        .map(|(n, c, _)| (n.to_string(), *c))
+        .collect();
+
+    let mut by_mem = procs;
+    by_mem.sort_by(|a, b| b.2.cmp(&a.2));
+    let top_mem_procs: Vec<(String, i64)> = by_mem
+        .iter()
+        .take(5)
+        .map(|(n, _, m)| (n.to_string(), *m))
+        .collect();
+
+    let (top_cpu_name, top_cpu_pct) = top_cpu_procs
+        .first()
+        .cloned()
         .unwrap_or_default();
-    let (top_mem_name, top_mem_mb) = top_mem
-        .map(|(n, v)| (n.to_string(), (v / 1024 / 1024) as i64))
+    let (top_mem_name, top_mem_mb) = top_mem_procs
+        .first()
+        .cloned()
         .unwrap_or_default();
 
     Some(PendingSample {
@@ -196,6 +214,8 @@ fn collect_sample(sys: &mut hbb_common::sysinfo::System) -> Option<PendingSample
         top_cpu_pct,
         top_mem_name,
         top_mem_mb,
+        top_cpu_procs,
+        top_mem_procs,
         attempts: 0,
     })
 }
@@ -277,6 +297,14 @@ async fn post_batch(batch: &[PendingSample]) -> Result<()> {
                 "top_cpu_pct":  s.top_cpu_pct,
                 "top_mem_name": s.top_mem_name,
                 "top_mem_mb":   s.top_mem_mb,
+                "top_processes": {
+                    "cpu": s.top_cpu_procs.iter()
+                        .map(|(n, p)| hbb_common::serde_json::json!({"name": n, "pct": p}))
+                        .collect::<Vec<_>>(),
+                    "mem": s.top_mem_procs.iter()
+                        .map(|(n, m)| hbb_common::serde_json::json!({"name": n, "mb": m}))
+                        .collect::<Vec<_>>(),
+                },
             })
         })
         .collect();