From c1653a2ac480bac397a535b0783996511abacb7d Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Sat, 31 Oct 2026 04:11:45 +0100
Subject: compute per-peer totals in /admin/stats once

---
 src/api/dashboard/mod.rs |  6 ++++--
 src/api/stats.rs         | 28 +++++++++++++++-------------
 2 files changed, 19 insertions(+), 15 deletions(-)

(limited to 'src')

diff --git a/src/api/dashboard/mod.rs b/src/api/dashboard/mod.rs
index ad907ed..0a15570 100644
--- a/src/api/dashboard/mod.rs
+++ b/src/api/dashboard/mod.rs
@@ -257,8 +257,10 @@ impl Graph {
 
 /// The snapshot: the node, its figures, its peers, and the map.
 async fn build(state: &AppState, graph: &Graph) -> JsonValue {
-    let stats = serde_json::to_value(super::stats::collect(state).await).unwrap_or_default();
-    let peers = serde_json::to_value(super::peers::peer_list(state).await).unwrap_or_default();
+    // The peers once, for their list and the figures' totals over them.
+    let list = super::peers::peer_list(state).await;
+    let stats = serde_json::to_value(super::stats::collect(state, &list).await).unwrap_or_default();
+    let peers = serde_json::to_value(&list).unwrap_or_default();
     let aliases = {
         let replica = state.doc.read().await;
         members::aliases(&replica.doc)
diff --git a/src/api/stats.rs b/src/api/stats.rs
index b9314e2..9e1b278 100644
--- a/src/api/stats.rs
+++ b/src/api/stats.rs
@@ -13,7 +13,7 @@ use std::collections::BTreeMap;
 
 use serde::Serialize;
 
-use super::peers::EpochInfo;
+use super::peers::{EpochInfo, PeerListResponse, peer_list};
 use crate::state::{AppState, Incidents};
 use crate::swarm::{members, stability, topology};
 use crate::transport::stats::TransportStats;
@@ -237,12 +237,12 @@ pub(crate) async fn get_relay_only_stats(
 
 /// `GET /admin/stats`.
 pub(crate) async fn get_stats(State(state): State<AppState>, headers: HeaderMap) -> Response {
-    let stats = collect(&state).await;
+    let list = peer_list(&state).await;
+    let stats = collect(&state, &list).await;
     let accept = headers
         .get(header::ACCEPT)
         .and_then(|value| value.to_str().ok());
     if prometheus::wanted(accept) {
-        let list = super::peers::peer_list(&state).await;
         let body = prometheus::render(&stats, &list);
         ([(header::CONTENT_TYPE, prometheus::CONTENT_TYPE)], body).into_response()
     } else {
@@ -250,8 +250,9 @@ pub(crate) async fn get_stats(State(state): State<AppState>, headers: HeaderMap)
     }
 }
 
-/// What `GET /admin/stats` answers as JSON, for others to show too (the dashboard).
-pub(crate) async fn collect(state: &AppState) -> StatsResponse {
+/// What `GET /admin/stats` answers as JSON, for others to show too (the dashboard); its
+/// totals over the peers from their list (`peer_list`), read once for both.
+pub(crate) async fn collect(state: &AppState, list: &PeerListResponse) -> StatsResponse {
     let node = state.stats.snapshot();
 
     let (heads, tier, remakes) = {
@@ -270,16 +271,17 @@ pub(crate) async fn collect(state: &AppState) -> StatsResponse {
     let (connected_fraction, observed) = stability::measured(state);
 
     let mut incidents = Incidents::default();
-    let mut last_from_neighbour: Option<tokio::time::Instant> = None;
+    let mut last_from_neighbour_secs: Option<u64> = None;
     let mut diverged_peers = 0;
-    for (peer, peer_state) in state.peers_snapshot().await {
-        let peer_state = peer_state.lock().await;
-        incidents.add(&peer_state.incidents);
-        if peer_state.diverged_since.is_some() {
+    for peer in list.peers.values() {
+        incidents.add(&peer.incidents);
+        if peer.diverged_for_secs.is_some() {
             diverged_peers += 1;
         }
-        if topology::is_neighbour(state, &peer) {
-            last_from_neighbour = last_from_neighbour.max(peer_state.last_sync_rx);
+        if peer.neighbour
+            && let Some(secs) = peer.last_sync_secs_ago
+        {
+            last_from_neighbour_secs = Some(last_from_neighbour_secs.map_or(secs, |s| s.min(secs)));
         }
     }
 
@@ -315,7 +317,7 @@ pub(crate) async fn collect(state: &AppState) -> StatsResponse {
             archived_epochs: remakes.archived_epochs,
         },
         sync: SyncStats {
-            last_from_neighbour_secs: last_from_neighbour.map(|at| at.elapsed().as_secs()),
+            last_from_neighbour_secs,
             diverged_peers,
             largest_received_bytes: node.largest_sync_received,
         },
-- 
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