Skip computing participation metrics if there is too many empty slots after head

Author: Povilas Liubauskas

fork_choice_control/src/controller.rs

@@ -484,6 +484,10 @@ where
         &self.state_cache
     }
 
+    pub fn store_config(&self) -> StoreConfig {
+        self.store_snapshot().store_config()
+    }
+
     pub(crate) fn store_snapshot(&self) -> Guard<Arc<Store<P>>> {
         self.store_snapshot.load()
     }
@@ -509,18 +513,6 @@ where
     }
 }
 
-#[cfg(test)]
-impl<P, E, W> Controller<P, E, W>
-where
-    P: Preset,
-    E: ExecutionEngine<P> + Clone + Send + Sync + 'static,
-    W: Wait,
-{
-    pub fn store_config(&self) -> StoreConfig {
-        self.store_snapshot().store_config()
-    }
-}
-
 /// A wrapper over [`JoinHandle`] that can be used to wait for the mutator thread to finish.
 ///
 /// We previously used [`std::process::exit`] to terminate the process when the mutator thread

metrics/src/server.rs

@@ -190,11 +190,17 @@ pub async fn prometheus_metrics<P: Preset, W: Wait>(
             .unwrap_or_default(),
     );
 
-    let epoch = misc::compute_epoch_at_slot::<P>(controller.head().value.slot());
-    // Take state at last slot in epoch
-    let slot = misc::compute_start_slot_at_epoch::<P>(epoch).saturating_sub(1);
-    if let Some(state) = controller.state_at_slot(slot)? {
-        scrape_epoch_statistics(&state.value, &metrics)?;
+    let head_slot = controller.head().value.slot();
+    let store_slot = controller.slot();
+    let max_empty_slots = controller.store_config().max_empty_slots;
+
+    if head_slot + max_empty_slots >= store_slot {
+        let epoch = misc::compute_epoch_at_slot::<P>(head_slot);
+        // Take state at last slot in epoch
+        let slot = misc::compute_start_slot_at_epoch::<P>(epoch).saturating_sub(1);
+        if let Some(state) = controller.state_at_slot(slot)? {
+            scrape_epoch_statistics(&state.value, &metrics)?;
+        }
     }
 
     TextEncoder::new()