IDONTWANT message optimisation to cutoff for smaller messages

beacon_node/lighthouse_network/gossipsub/src/behaviour.rs

@@ -1812,9 +1812,6 @@ where
         // Calculate the message id on the transformed data.
         let msg_id = self.config.message_id(&message);
 
-        // Broadcast IDONTWANT messages.
-        self.send_idontwant(&raw_message, &msg_id, propagation_source);
-
         // Check the validity of the message
         // Peers get penalized if this message is invalid. We don't add it to the duplicate cache
         // and instead continually penalize peers that repeatedly send this message.
@@ -1828,8 +1825,13 @@ where
                 peer_score.duplicated_message(propagation_source, &msg_id, &message.topic);
             }
             self.mcache.observe_duplicate(&msg_id, propagation_source);
+
             return;
         }
+
+        // Broadcast IDONTWANT messages.
+        self.send_idontwant(&raw_message, &msg_id, propagation_source);
+
         tracing::debug!(
             message=%msg_id,
             "Put message in duplicate_cache and resolve promises"
@@ -2699,6 +2701,10 @@ where
             return;
         };
 
+        if message.raw_protobuf_len() < self.config.idontwant_message_size_threshold(){
+            return;
+        }
+
         let iwant_peers = self.gossip_promises.peers_for_message(msg_id);
 
         let recipient_peers = mesh_peers

beacon_node/lighthouse_network/gossipsub/src/config.rs

@@ -98,6 +98,7 @@ pub struct Config {
     connection_handler_queue_len: usize,
     connection_handler_publish_duration: Duration,
     connection_handler_forward_duration: Duration,
+    idontwant_message_size_threshold: usize,
 }
 
 impl Config {
@@ -370,6 +371,16 @@ impl Config {
     pub fn forward_queue_duration(&self) -> Duration {
         self.connection_handler_forward_duration
     }
+
+    // Controls the message size threshold for which IDONTWANT messages are sent.
+    // Sending IDONTWANT messages for small messages can have a negative effect to the overall
+    // traffic and CPU load. This acts as a lower bound cutoff for the message size to which 
+    // IDONTWANT won't be sent to peers. Only works if the peers support Gossipsub1.3 
+    // (see https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.2.md#idontwant-message)
+    // default is 1kB
+    pub fn idontwant_message_size_threshold(&self) -> usize{
+        self.idontwant_message_size_threshold
+    }
 }
 
 impl Default for Config {
@@ -440,6 +451,7 @@ impl Default for ConfigBuilder {
                 connection_handler_queue_len: 5000,
                 connection_handler_publish_duration: Duration::from_secs(5),
                 connection_handler_forward_duration: Duration::from_millis(1000),
+                idontwant_message_size_threshold: 1000,
             },
             invalid_protocol: false,
         }
@@ -825,6 +837,17 @@ impl ConfigBuilder {
         self
     }
 
+    // Controls the message size threshold for which IDONTWANT messages are sent.
+    // Sending IDONTWANT messages for small messages can have a negative effect to the overall
+    // traffic and CPU load. This acts as a lower bound cutoff for the message size to which 
+    // IDONTWANT won't be sent to peers. Only works if the peers support Gossipsub1.3 
+    // (see https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.2.md#idontwant-message)
+    // default is 1kB
+    pub fn idontwant_message_size_threshold(&mut self, size: usize) -> &mut Self {
+        self.config.idontwant_message_size_threshold = size;
+        self
+    }
+
     /// Constructs a [`Config`] from the given configuration and validates the settings.
     pub fn build(&self) -> Result<Config, ConfigBuilderError> {
         // check all constraints on config
@@ -895,6 +918,7 @@ impl std::fmt::Debug for Config {
             "published_message_ids_cache_time",
             &self.published_message_ids_cache_time,
         );
+        let _ = builder.field("idontwant_message_size_threhold",&self.idontwant_message_size_threshold);
         builder.finish()
     }
 }