feat(MR): [MR-649] Roll out best-effort calls to the first few subnets

List a few subnets in the BestEffortResponsesFeature::SpecificSubnets under the FeatureFlags default. This will have the ic0_call_with_best_effort_response() API call on these subnets actually set a deadline on the calls being constructed. And allow best-effort requests to be routed between these subnets only.

Also reduce the default subnet_message_memory_capacity on all subnets from 25 GB to 15 GB, to make place for a potential 5 GB of best-effort messages plus a potential 1 M callbacks. Apart from brief spikes, usually associated with heartbeat / global timer storms, subnet message memory usage is virtually always in the low single digit GBs, so the reduction of the limit will make no practical difference.

rs/config/src/embedders.rs

@@ -159,14 +159,13 @@ pub struct FeatureFlags {
 
 impl Default for FeatureFlags {
     fn default() -> Self {
-        // TODO(MR-649): Comment out for stage 1b -- rollout to specific subnets.
-        // use ic_types::PrincipalId;
-        // use std::str::FromStr;
-        // let subnet_id = |id_str: &str| SubnetId::new(PrincipalId::from_str(id_str).unwrap());
+        use ic_types::PrincipalId;
+        use std::str::FromStr;
+        let subnet_id = |id_str: &str| SubnetId::new(PrincipalId::from_str(id_str).unwrap());
         let enabled_subnets = vec![
-            // subnet_id("eq6en-6jqla-fbu5s-daskr-h6hx2-376n5-iqabl-qgrng-gfqmv-n3yjr-mqe"),
-            // subnet_id("2fq7c-slacv-26cgz-vzbx2-2jrcs-5edph-i5s2j-tck77-c3rlz-iobzx-mqe"),
-            // subnet_id("4zbus-z2bmt-ilreg-xakz4-6tyre-hsqj4-slb4g-zjwqo-snjcc-iqphi-3qe"),
+            subnet_id("eq6en-6jqla-fbu5s-daskr-h6hx2-376n5-iqabl-qgrng-gfqmv-n3yjr-mqe"),
+            subnet_id("2fq7c-slacv-26cgz-vzbx2-2jrcs-5edph-i5s2j-tck77-c3rlz-iobzx-mqe"),
+            subnet_id("4zbus-z2bmt-ilreg-xakz4-6tyre-hsqj4-slb4g-zjwqo-snjcc-iqphi-3qe"),
         ];
 
         Self {
@@ -346,3 +345,38 @@ impl Default for Config {
         Self::new()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ic_types::PrincipalId;
+
+    const SUBNET_1: SubnetId = SubnetId::new(PrincipalId::new(1, [1; 29]));
+    const SUBNET_2: SubnetId = SubnetId::new(PrincipalId::new(1, [2; 29]));
+
+    #[test]
+    fn test_best_effort_responses_feature_specific_subnets() {
+        let best_effort_responses = BestEffortResponsesFeature::SpecificSubnets(vec![SUBNET_1]);
+
+        assert!(best_effort_responses.is_enabled_on(&SUBNET_1, SubnetType::Application));
+        assert!(best_effort_responses.is_enabled_on(&SUBNET_1, SubnetType::System));
+        assert!(!best_effort_responses.is_enabled_on(&SUBNET_2, SubnetType::Application));
+        assert!(!best_effort_responses.is_enabled_on(&SUBNET_2, SubnetType::System));
+    }
+
+    #[test]
+    fn test_best_effort_responses_feature_application_subnets_only() {
+        let best_effort_responses = BestEffortResponsesFeature::ApplicationSubnetsOnly;
+
+        assert!(best_effort_responses.is_enabled_on(&SUBNET_1, SubnetType::Application));
+        assert!(!best_effort_responses.is_enabled_on(&SUBNET_1, SubnetType::System));
+    }
+
+    #[test]
+    fn test_best_effort_responses_feature_enabled() {
+        let best_effort_responses = BestEffortResponsesFeature::Enabled;
+
+        assert!(best_effort_responses.is_enabled_on(&SUBNET_1, SubnetType::Application));
+        assert!(best_effort_responses.is_enabled_on(&SUBNET_1, SubnetType::System));
+    }
+}

rs/config/src/execution_environment.rs

@@ -31,7 +31,7 @@ const SUBNET_MEMORY_CAPACITY: NumBytes = NumBytes::new(TIB);
 /// Guaranteed response message memory usage is calculated as the total size of
 /// enqueued guaranteed responses; plus the maximum allowed response size per
 /// reserved guaranteed response slot.
-const SUBNET_GUARANTEED_RESPONSE_MESSAGE_MEMORY_CAPACITY: NumBytes = NumBytes::new(25 * GIB);
+const SUBNET_GUARANTEED_RESPONSE_MESSAGE_MEMORY_CAPACITY: NumBytes = NumBytes::new(15 * GIB);
 
 /// The limit on how much memory may be used by all guaranteed response messages
 /// on a given subnet at the end of a round.