metrics on rent partitions (solana-labs#19728)

runtime/src/bank.rs

@@ -3864,10 +3864,18 @@ impl Bank {
         }
 
         let mut measure = Measure::start("collect_rent_eagerly-ms");
-        for partition in self.rent_collection_partitions() {
-            self.collect_rent_in_partition(partition);
-        }
+        let partitions = self.rent_collection_partitions();
+        let count = partitions.len();
+        let account_count: usize = partitions
+            .into_iter()
+            .map(|partition| self.collect_rent_in_partition(partition))
+            .sum();
         measure.stop();
+        datapoint_info!(
+            "collect_rent_eagerly",
+            ("accounts", account_count, i64),
+            ("partitions", count, i64)
+        );
         inc_new_counter_info!("collect_rent_eagerly-ms", measure.as_ms() as usize);
     }
 
@@ -3904,7 +3912,7 @@ impl Bank {
         }
     }
 
-    fn collect_rent_in_partition(&self, partition: Partition) {
+    fn collect_rent_in_partition(&self, partition: Partition) -> usize {
         let subrange = Self::pubkey_range_from_partition(partition);
 
         let accounts = self
@@ -3934,8 +3942,7 @@ impl Bank {
         }
         self.collected_rent.fetch_add(total_rent, Relaxed);
         self.rewards.write().unwrap().append(&mut rent_debits.0);
-
-        datapoint_info!("collect_rent_eagerly", ("accounts", account_count, i64));
+        account_count
     }
 
     // Mostly, the pair (start_index & end_index) is equivalent to this range: