add truncate metrics

crates/net/network/src/transactions/mod.rs

@@ -972,6 +972,10 @@ where
                 }
             }
 
+            // The original capacity reservation may have been too large, so we shrink the vector to
+            // the actual number of transactions to import.
+            // new_txs.shrink_to_fit();
+
             // import new transactions as a batch to minimize lock contention on the underlying pool
             if !new_txs.is_empty() {
                 let pool = self.pool.clone();

crates/transaction-pool/src/metrics.rs

@@ -41,6 +41,18 @@ pub struct TxPoolMetrics {
 
     /// How often the pool was updated after the canonical state changed
     pub(crate) performed_state_updates: Counter,
+
+    /// Total `discard_worst` calls
+    pub(crate) discard_worst_calls: Counter,
+
+    /// How long it took the pool to `discard_worst`
+    pub(crate) discard_worst_duration: Gauge,
+
+    /// How many times `discard_worst` looped
+    pub(crate) discard_worst_loops: Gauge,
+
+    /// How many transactions were removed in the last `discard_worst` call
+    pub(crate) discard_worst_removed: Gauge,
 }
 
 /// Transaction pool blobstore metrics

crates/transaction-pool/src/pool/txpool.rs

@@ -756,6 +756,10 @@ impl<T: TransactionOrdering> TxPool<T> {
     /// This returns all transactions that were removed from the entire pool.
     pub(crate) fn discard_worst(&mut self) -> Vec<Arc<ValidPoolTransaction<T::Transaction>>> {
         let mut removed = Vec::new();
+        self.metrics.discard_worst_calls.increment(1);
+
+        let now = std::time::Instant::now();
+        let mut loops = 0;
 
         // Helper macro that discards the worst transactions for the pools
         macro_rules! discard_worst {
@@ -766,6 +770,7 @@ impl<T: TransactionOrdering> TxPool<T> {
                         .$limit
                         .is_exceeded($this.$pool.len(), $this.$pool.size())
                     {
+                        loops += 1;
                         trace!(
                             "discarding transactions from {}, limit: {:?}, curr size: {}, curr len: {}",
                             stringify!($pool),
@@ -813,6 +818,11 @@ impl<T: TransactionOrdering> TxPool<T> {
             ]
         );
 
+        let elapsed = now.elapsed();
+        self.metrics.discard_worst_duration.set(elapsed.as_secs_f64());
+        self.metrics.discard_worst_removed.set(removed.len() as f64);
+        self.metrics.discard_worst_loops.set(loops as f64);
+
         removed
     }