Stable futures (#879)

* Port eth1 lib to use stable futures

* Port eth1_test_rig to stable futures

* Port eth1 tests to stable futures

* Port genesis service to stable futures

* Port genesis tests to stable futures

* Port beacon_chain to stable futures

* Port lcli to stable futures

* Fix eth1_test_rig (#1014)

* Fix lcli

* Port timer to stable futures

* Fix timer

* Port websocket_server to stable futures

* Port notifier to stable futures

* Add TODOS

* Update hashmap hashset to stable futures

* Adds panic test to hashset delay

* Port remote_beacon_node to stable futures

* Fix lcli merge conflicts

* Non rpc stuff compiles

* protocol.rs compiles

* Port websockets, timer and notifier to stable futures (#1035)

* Fix lcli

* Port timer to stable futures

* Fix timer

* Port websocket_server to stable futures

* Port notifier to stable futures

* Add TODOS

* Port remote_beacon_node to stable futures

* Partial eth2-libp2p stable future upgrade

* Finished first round of fighting RPC types

* Further progress towards porting eth2-libp2p adds caching to discovery

* Update behaviour

* RPC handler to stable futures

* Update RPC to master libp2p

* Network service additions

* Fix the fallback transport construction (#1102)

* Correct warning

* Remove hashmap delay

* Compiling version of eth2-libp2p

* Update all crates versions

* Fix conversion function and add tests (#1113)

* Port validator_client to stable futures (#1114)

* Add PH & MS slot clock changes

* Account for genesis time

* Add progress on duties refactor

* Add simple is_aggregator bool to val subscription

* Start work on attestation_verification.rs

* Add progress on ObservedAttestations

* Progress with ObservedAttestations

* Fix tests

* Add observed attestations to the beacon chain

* Add attestation observation to processing code

* Add progress on attestation verification

* Add first draft of ObservedAttesters

* Add more tests

* Add observed attesters to beacon chain

* Add observers to attestation processing

* Add more attestation verification

* Create ObservedAggregators map

* Remove commented-out code

* Add observed aggregators into chain

* Add progress

* Finish adding features to attestation verification

* Ensure beacon chain compiles

* Link attn verification into chain

* Integrate new attn verification in chain

* Remove old attestation processing code

* Start trying to fix beacon_chain tests

* Split adding into pools into two functions

* Add aggregation to harness

* Get test harness working again

* Adjust the number of aggregators for test harness

* Fix edge-case in harness

* Integrate new attn processing in network

* Fix compile bug in validator_client

* Update validator API endpoints

* Fix aggreagation in test harness

* Fix enum thing

* Fix attestation observation bug:

* Patch failing API tests

* Start adding comments to attestation verification

* Remove unused attestation field

* Unify "is block known" logic

* Update comments

* Supress fork choice errors for network processing

* Add todos

* Tidy

* Add gossip attn tests

* Disallow test harness to produce old attns

* Comment out in-progress tests

* Partially address pruning tests

* Fix failing store test

* Add aggregate tests

* Add comments about which spec conditions we check

* Dont re-aggregate

* Split apart test harness attn production

* Fix compile error in network

* Make progress on commented-out test

* Fix skipping attestation test

* Add fork choice verification tests

* Tidy attn tests, remove dead code

* Remove some accidentally added code

* Fix clippy lint

* Rename test file

* Add block tests, add cheap block proposer check

* Rename block testing file

* Add observed_block_producers

* Tidy

* Switch around block signature verification

* Finish block testing

* Remove gossip from signature tests

* First pass of self review

* Fix deviation in spec

* Update test spec tags

* Start moving over to hashset

* Finish moving observed attesters to hashmap

* Move aggregation pool over to hashmap

* Make fc attn borrow again

* Fix rest_api compile error

* Fix missing comments

* Fix monster test

* Uncomment increasing slots test

* Address remaining comments

* Remove unsafe, use cfg test

* Remove cfg test flag

* Fix dodgy comment

* Revert "Update hashmap hashset to stable futures"

This reverts commit d432378a3c.

* Revert "Adds panic test to hashset delay"

This reverts commit 281502396f.

* Ported attestation_service

* Ported duties_service

* Ported fork_service

* More ports

* Port block_service

* Minor fixes

* VC compiles

* Update TODOS

* Borrow self where possible

* Ignore aggregates that are already known.

* Unify aggregator modulo logic

* Fix typo in logs

* Refactor validator subscription logic

* Avoid reproducing selection proof

* Skip HTTP call if no subscriptions

* Rename DutyAndState -> DutyAndProof

* Tidy logs

* Print root as dbg

* Fix compile errors in tests

* Fix compile error in test

* Re-Fix attestation and duties service

* Minor fixes

Co-authored-by: Paul Hauner <paul@paulhauner.com>

* Network crate update to stable futures

* Port account_manager to stable futures (#1121)

* Port account_manager to stable futures

* Run async fns in tokio environment

* Port rest_api crate to stable futures (#1118)

* Port rest_api lib to stable futures

* Reduce tokio features

* Update notifier to stable futures

* Builder update

* Further updates

* Convert self referential async functions

* stable futures fixes (#1124)

* Fix eth1 update functions

* Fix genesis and client

* Fix beacon node lib

* Return appropriate runtimes from environment

* Fix test rig

* Refactor eth1 service update

* Upgrade simulator to stable futures

* Lighthouse compiles on stable futures

* Remove println debugging statement

* Update libp2p service, start rpc test upgrade

* Update network crate for new libp2p

* Update tokio::codec to futures_codec (#1128)

* Further work towards RPC corrections

* Correct http timeout and network service select

* Use tokio runtime for libp2p

* Revert "Update tokio::codec to futures_codec (#1128)"

This reverts commit e57aea924a.

* Upgrade RPC libp2p tests

* Upgrade secio fallback test

* Upgrade gossipsub examples

* Clean up RPC protocol

* Test fixes (#1133)

* Correct websocket timeout and run on os thread

* Fix network test

* Clean up PR

* Correct tokio tcp move attestation service tests

* Upgrade attestation service tests

* Correct network test

* Correct genesis test

* Test corrections

* Log info when block is received

* Modify logs and update attester service events

* Stable futures: fixes to vc, eth1 and account manager (#1142)

* Add local testnet scripts

* Remove whiteblock script

* Rename local testnet script

* Move spawns onto handle

* Fix VC panic

* Initial fix to block production issue

* Tidy block producer fix

* Tidy further

* Add local testnet clean script

* Run cargo fmt

* Tidy duties service

* Tidy fork service

* Tidy ForkService

* Tidy AttestationService

* Tidy notifier

* Ensure await is not suppressed in eth1

* Ensure await is not suppressed in account_manager

* Use .ok() instead of .unwrap_or(())

* RPC decoding test for proto

* Update discv5 and eth2-libp2p deps

* Fix lcli double runtime issue (#1144)

* Handle stream termination and dialing peer errors

* Correct peer_info variant types

* Remove unnecessary warnings

* Handle subnet unsubscription removal and improve logigng

* Add logs around ping

* Upgrade discv5 and improve logging

* Handle peer connection status for multiple connections

* Improve network service logging

* Improve logging around peer manager

* Upgrade swarm poll centralise peer management

* Identify clients on error

* Fix `remove_peer` in sync (#1150)

* remove_peer removes from all chains

* Remove logs

* Fix early return from loop

* Improved logging, fix panic

* Partially correct tests

* Stable futures: Vc sync (#1149)

* Improve syncing heuristic

* Add comments

* Use safer method for tolerance

* Fix tests

* Stable futures: Fix VC bug, update agg pool, add more metrics (#1151)

* Expose epoch processing summary

* Expose participation metrics to prometheus

* Switch to f64

* Reduce precision

* Change precision

* Expose observed attesters metrics

* Add metrics for agg/unagg attn counts

* Add metrics for gossip rx

* Add metrics for gossip tx

* Adds ignored attns to prom

* Add attestation timing

* Add timer for aggregation pool sig agg

* Add write lock timer for agg pool

* Add more metrics to agg pool

* Change map lock code

* Add extra metric to agg pool

* Change lock handling in agg pool

* Change .write() to .read()

* Add another agg pool timer

* Fix for is_aggregator

* Fix pruning bug

Co-authored-by: pawan <pawandhananjay@gmail.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>

beacon_node/beacon_chain/src/attestation_verification.rs

@@ -847,7 +847,7 @@ where
             // The state roots are not useful for the shuffling, so there's no need to
             // compute them.
             per_slot_processing(&mut state, Some(Hash256::zero()), &chain.spec)
-                .map_err(|e| BeaconChainError::from(e))?
+                .map_err(|e| BeaconChainError::from(e))?;
         }
 
         metrics::stop_timer(state_skip_timer);

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -553,7 +553,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                     // Note: supplying some `state_root` when it is known would be a cheap and easy
                     // optimization.
                     match per_slot_processing(&mut state, skip_state_root, &self.spec) {
-                        Ok(()) => (),
+                        Ok(_) => (),
                         Err(e) => {
                             warn!(
                                 self.log,
@@ -863,7 +863,14 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         attestation: Attestation<T::EthSpec>,
     ) -> Result<VerifiedUnaggregatedAttestation<T>, AttestationError> {
-        VerifiedUnaggregatedAttestation::verify(attestation, self)
+        metrics::inc_counter(&metrics::UNAGGREGATED_ATTESTATION_PROCESSING_REQUESTS);
+        let _timer =
+            metrics::start_timer(&metrics::UNAGGREGATED_ATTESTATION_GOSSIP_VERIFICATION_TIMES);
+
+        VerifiedUnaggregatedAttestation::verify(attestation, self).map(|v| {
+            metrics::inc_counter(&metrics::UNAGGREGATED_ATTESTATION_PROCESSING_SUCCESSES);
+            v
+        })
     }
 
     /// Accepts some `SignedAggregateAndProof` from the network and attempts to verify it,
@@ -872,7 +879,14 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         signed_aggregate: SignedAggregateAndProof<T::EthSpec>,
     ) -> Result<VerifiedAggregatedAttestation<T>, AttestationError> {
-        VerifiedAggregatedAttestation::verify(signed_aggregate, self)
+        metrics::inc_counter(&metrics::AGGREGATED_ATTESTATION_PROCESSING_REQUESTS);
+        let _timer =
+            metrics::start_timer(&metrics::AGGREGATED_ATTESTATION_GOSSIP_VERIFICATION_TIMES);
+
+        VerifiedAggregatedAttestation::verify(signed_aggregate, self).map(|v| {
+            metrics::inc_counter(&metrics::AGGREGATED_ATTESTATION_PROCESSING_SUCCESSES);
+            v
+        })
     }
 
     /// Accepts some attestation-type object and attempts to verify it in the context of fork
@@ -887,6 +901,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         unverified_attestation: &'a impl IntoForkChoiceVerifiedAttestation<'a, T>,
     ) -> Result<ForkChoiceVerifiedAttestation<'a, T>, AttestationError> {
+        let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_APPLY_TO_FORK_CHOICE);
+
         let verified = unverified_attestation.into_fork_choice_verified_attestation(self)?;
         let indexed_attestation = verified.indexed_attestation();
         self.fork_choice
@@ -907,6 +923,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         unaggregated_attestation: VerifiedUnaggregatedAttestation<T>,
     ) -> Result<VerifiedUnaggregatedAttestation<T>, AttestationError> {
+        let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_APPLY_TO_AGG_POOL);
+
         let attestation = unaggregated_attestation.attestation();
 
         match self.naive_aggregation_pool.insert(attestation) {
@@ -950,6 +968,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         signed_aggregate: VerifiedAggregatedAttestation<T>,
     ) -> Result<VerifiedAggregatedAttestation<T>, AttestationError> {
+        let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_APPLY_TO_OP_POOL);
+
         // If there's no eth1 chain then it's impossible to produce blocks and therefore
         // useless to put things in the op pool.
         if self.eth1_chain.is_some() {

beacon_node/beacon_chain/src/block_verification.rs

@@ -54,10 +54,12 @@ use slot_clock::SlotClock;
 use ssz::Encode;
 use state_processing::{
     block_signature_verifier::{BlockSignatureVerifier, Error as BlockSignatureVerifierError},
-    per_block_processing, per_slot_processing, BlockProcessingError, BlockSignatureStrategy,
-    SlotProcessingError,
+    per_block_processing,
+    per_epoch_processing::EpochProcessingSummary,
+    per_slot_processing, BlockProcessingError, BlockSignatureStrategy, SlotProcessingError,
 };
 use std::borrow::Cow;
+use std::convert::TryFrom;
 use std::fs;
 use std::io::Write;
 use store::{Error as DBError, StateBatch};
@@ -238,7 +240,7 @@ pub fn signature_verify_chain_segment<T: BeaconChainTypes>(
 /// the p2p network.
 pub struct GossipVerifiedBlock<T: BeaconChainTypes> {
     pub block: SignedBeaconBlock<T::EthSpec>,
-    block_root: Hash256,
+    pub block_root: Hash256,
     parent: BeaconSnapshot<T::EthSpec>,
 }
 
@@ -556,6 +558,8 @@ impl<T: BeaconChainTypes> FullyVerifiedBlock<T> {
             });
         }
 
+        let mut summaries = vec![];
+
         // Transition the parent state to the block slot.
         let mut state = parent.beacon_state;
         let distance = block.slot().as_u64().saturating_sub(state.slot.as_u64());
@@ -571,9 +575,12 @@ impl<T: BeaconChainTypes> FullyVerifiedBlock<T> {
                 state_root
             };
 
-            per_slot_processing(&mut state, Some(state_root), &chain.spec)?;
+            per_slot_processing(&mut state, Some(state_root), &chain.spec)?
+                .map(|summary| summaries.push(summary));
         }
 
+        expose_participation_metrics(&summaries);
+
         metrics::stop_timer(catchup_timer);
 
         /*
@@ -891,6 +898,45 @@ fn get_signature_verifier<'a, E: EthSpec>(
     )
 }
 
+fn expose_participation_metrics(summaries: &[EpochProcessingSummary]) {
+    if !cfg!(feature = "participation_metrics") {
+        return;
+    }
+
+    for summary in summaries {
+        let b = &summary.total_balances;
+
+        metrics::maybe_set_float_gauge(
+            &metrics::PARTICIPATION_PREV_EPOCH_ATTESTER,
+            participation_ratio(b.previous_epoch_attesters(), b.previous_epoch()),
+        );
+
+        metrics::maybe_set_float_gauge(
+            &metrics::PARTICIPATION_PREV_EPOCH_TARGET_ATTESTER,
+            participation_ratio(b.previous_epoch_target_attesters(), b.previous_epoch()),
+        );
+
+        metrics::maybe_set_float_gauge(
+            &metrics::PARTICIPATION_PREV_EPOCH_HEAD_ATTESTER,
+            participation_ratio(b.previous_epoch_head_attesters(), b.previous_epoch()),
+        );
+    }
+}
+
+fn participation_ratio(section: u64, total: u64) -> Option<f64> {
+    // Reduce the precision to help ensure we fit inside a u32.
+    const PRECISION: u64 = 100_000_000;
+
+    let section: f64 = u32::try_from(section / PRECISION).ok()?.into();
+    let total: f64 = u32::try_from(total / PRECISION).ok()?.into();
+
+    if total > 0_f64 {
+        Some(section / total)
+    } else {
+        None
+    }
+}
+
 fn write_state<T: EthSpec>(prefix: &str, state: &BeaconState<T>, log: &Logger) {
     if WRITE_BLOCK_PROCESSING_SSZ {
         let root = state.tree_hash_root();

beacon_node/beacon_chain/src/eth1_chain.rs

@@ -1,7 +1,6 @@
 use crate::metrics;
 use eth1::{Config as Eth1Config, Eth1Block, Service as HttpService};
 use eth2_hashing::hash;
-use futures::Future;
 use slog::{debug, error, trace, Logger};
 use ssz::{Decode, Encode};
 use ssz_derive::{Decode, Encode};
@@ -286,11 +285,10 @@ impl<T: EthSpec, S: Store<T>> CachingEth1Backend<T, S> {
     }
 
     /// Starts the routine which connects to the external eth1 node and updates the caches.
-    pub fn start(
-        &self,
-        exit: tokio::sync::oneshot::Receiver<()>,
-    ) -> impl Future<Item = (), Error = ()> {
-        self.core.auto_update(exit)
+    pub fn start(&self, exit: tokio::sync::oneshot::Receiver<()>) {
+        // don't need to spawn as a task is being spawned in auto_update
+        // TODO: check if this is correct
+        HttpService::auto_update(self.core.clone(), exit);
     }
 
     /// Instantiates `self` from an existing service.

beacon_node/beacon_chain/src/metrics.rs

@@ -1,6 +1,7 @@
 use crate::{BeaconChain, BeaconChainTypes};
 pub use lighthouse_metrics::*;
-use types::{BeaconState, Epoch, Hash256, Slot};
+use slot_clock::SlotClock;
+use types::{BeaconState, Epoch, EthSpec, Hash256, Slot};
 
 lazy_static! {
     /*
@@ -79,25 +80,81 @@ lazy_static! {
         "Number of attestations in a block"
     );
 
+    /*
+     * Unaggregated Attestation Verification
+     */
+    pub static ref UNAGGREGATED_ATTESTATION_PROCESSING_REQUESTS: Result<IntCounter> = try_create_int_counter(
+        "beacon_unaggregated_attestation_processing_requests_total",
+        "Count of all unaggregated attestations submitted for processing"
+    );
+    pub static ref UNAGGREGATED_ATTESTATION_PROCESSING_SUCCESSES: Result<IntCounter> = try_create_int_counter(
+        "beacon_unaggregated_attestation_processing_successes_total",
+        "Number of unaggregated attestations verified for gossip"
+    );
+    pub static ref UNAGGREGATED_ATTESTATION_GOSSIP_VERIFICATION_TIMES: Result<Histogram> = try_create_histogram(
+        "beacon_unaggregated_attestation_gossip_verification_seconds",
+        "Full runtime of aggregated attestation gossip verification"
+    );
+
+    /*
+     * Aggregated Attestation Verification
+     */
+    pub static ref AGGREGATED_ATTESTATION_PROCESSING_REQUESTS: Result<IntCounter> = try_create_int_counter(
+        "beacon_aggregated_attestation_processing_requests_total",
+        "Count of all aggregated attestations submitted for processing"
+    );
+    pub static ref AGGREGATED_ATTESTATION_PROCESSING_SUCCESSES: Result<IntCounter> = try_create_int_counter(
+        "beacon_aggregated_attestation_processing_successes_total",
+        "Number of aggregated attestations verified for gossip"
+    );
+    pub static ref AGGREGATED_ATTESTATION_GOSSIP_VERIFICATION_TIMES: Result<Histogram> = try_create_histogram(
+        "beacon_aggregated_attestation_gossip_verification_seconds",
+        "Full runtime of aggregated attestation gossip verification"
+    );
+
+    /*
+     * General Attestation Processing
+     */
+    pub static ref ATTESTATION_PROCESSING_APPLY_TO_FORK_CHOICE: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_apply_to_fork_choice",
+        "Time spent applying an attestation to fork choice"
+    );
+    pub static ref ATTESTATION_PROCESSING_APPLY_TO_AGG_POOL: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_apply_to_agg_pool",
+        "Time spent applying an attestation to the naive aggregation pool"
+    );
+    pub static ref ATTESTATION_PROCESSING_AGG_POOL_MAPS_WRITE_LOCK: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_agg_pool_maps_write_lock",
+        "Time spent waiting for the maps write lock when adding to the agg poll"
+    );
+    pub static ref ATTESTATION_PROCESSING_AGG_POOL_PRUNE: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_agg_pool_prune",
+        "Time spent for the agg pool to prune"
+    );
+    pub static ref ATTESTATION_PROCESSING_AGG_POOL_INSERT: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_agg_pool_insert",
+        "Time spent for the outer pool.insert() function of agg pool"
+    );
+    pub static ref ATTESTATION_PROCESSING_AGG_POOL_CORE_INSERT: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_agg_pool_core_insert",
+        "Time spent for the core map.insert() function of agg pool"
+    );
+    pub static ref ATTESTATION_PROCESSING_AGG_POOL_AGGREGATION: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_agg_pool_aggregation",
+        "Time spent doing signature aggregation when adding to the agg poll"
+    );
+    pub static ref ATTESTATION_PROCESSING_AGG_POOL_CREATE_MAP: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_agg_pool_create_map",
+        "Time spent for creating a map for a new slot"
+    );
+    pub static ref ATTESTATION_PROCESSING_APPLY_TO_OP_POOL: Result<Histogram> = try_create_histogram(
+        "beacon_attestation_processing_apply_to_op_pool",
+        "Time spent applying an attestation to the block inclusion pool"
+    );
+
     /*
      * Attestation Processing
      */
-    pub static ref ATTESTATION_PROCESSING_REQUESTS: Result<IntCounter> = try_create_int_counter(
-        "beacon_attestation_processing_requests_total",
-        "Count of all attestations submitted for processing"
-    );
-    pub static ref ATTESTATION_PROCESSING_SUCCESSES: Result<IntCounter> = try_create_int_counter(
-        "beacon_attestation_processing_successes_total",
-        "total_attestation_processing_successes"
-    );
-    pub static ref ATTESTATION_PROCESSING_TIMES: Result<Histogram> = try_create_histogram(
-        "beacon_attestation_processing_seconds",
-        "Full runtime of attestation processing"
-    );
-    pub static ref ATTESTATION_PROCESSING_INITIAL_VALIDATION_TIMES: Result<Histogram> = try_create_histogram(
-        "beacon_attestation_processing_initial_validation_seconds",
-        "Time spent on the initial_validation of attestation processing"
-    );
     pub static ref ATTESTATION_PROCESSING_SHUFFLING_CACHE_WAIT_TIMES: Result<Histogram> = try_create_histogram(
         "beacon_attestation_processing_shuffling_cache_wait_seconds",
         "Time spent on waiting for the shuffling cache lock during attestation processing"
@@ -251,6 +308,34 @@ lazy_static! {
         try_create_int_gauge("beacon_op_pool_proposer_slashings_total", "Count of proposer slashings in the op pool");
     pub static ref OP_POOL_NUM_VOLUNTARY_EXITS: Result<IntGauge> =
         try_create_int_gauge("beacon_op_pool_voluntary_exits_total", "Count of voluntary exits in the op pool");
+
+    /*
+     * Participation Metrics
+     */
+    pub static ref PARTICIPATION_PREV_EPOCH_ATTESTER: Result<Gauge> = try_create_float_gauge(
+        "beacon_participation_prev_epoch_attester",
+        "Ratio of attesting balances to total balances"
+    );
+    pub static ref PARTICIPATION_PREV_EPOCH_TARGET_ATTESTER: Result<Gauge> = try_create_float_gauge(
+        "beacon_participation_prev_epoch_target_attester",
+        "Ratio of target-attesting balances to total balances"
+    );
+    pub static ref PARTICIPATION_PREV_EPOCH_HEAD_ATTESTER: Result<Gauge> = try_create_float_gauge(
+        "beacon_participation_prev_epoch_head_attester",
+        "Ratio of head-attesting balances to total balances"
+    );
+
+    /*
+     * Attestation Observation Metrics
+     */
+    pub static ref ATTN_OBSERVATION_PREV_EPOCH_ATTESTERS: Result<IntGauge> = try_create_int_gauge(
+        "beacon_attn_observation_epoch_attesters",
+        "Count of attesters that have been seen by the beacon chain in the previous epoch"
+    );
+    pub static ref ATTN_OBSERVATION_PREV_EPOCH_AGGREGATORS: Result<IntGauge> = try_create_int_gauge(
+        "beacon_attn_observation_epoch_aggregators",
+        "Count of aggregators that have been seen by the beacon chain in the previous epoch"
+    );
 }
 
 /// Scrape the `beacon_chain` for metrics that are not constantly updated (e.g., the present slot,
@@ -260,6 +345,10 @@ pub fn scrape_for_metrics<T: BeaconChainTypes>(beacon_chain: &BeaconChain<T>) {
         scrape_head_state::<T>(&head.beacon_state, head.beacon_state_root)
     }
 
+    if let Some(slot) = beacon_chain.slot_clock.now() {
+        scrape_attestation_observation(slot, beacon_chain);
+    }
+
     set_gauge_by_usize(
         &OP_POOL_NUM_ATTESTATIONS,
         beacon_chain.op_pool.num_attestations(),
@@ -332,6 +421,24 @@ fn scrape_head_state<T: BeaconChainTypes>(state: &BeaconState<T::EthSpec>, state
     set_gauge_by_u64(&HEAD_STATE_ETH1_DEPOSIT_INDEX, state.eth1_deposit_index);
 }
 
+fn scrape_attestation_observation<T: BeaconChainTypes>(slot_now: Slot, chain: &BeaconChain<T>) {
+    let prev_epoch = slot_now.epoch(T::EthSpec::slots_per_epoch()) - 1;
+
+    if let Some(count) = chain
+        .observed_attesters
+        .observed_validator_count(prev_epoch)
+    {
+        set_gauge_by_usize(&ATTN_OBSERVATION_PREV_EPOCH_ATTESTERS, count);
+    }
+
+    if let Some(count) = chain
+        .observed_aggregators
+        .observed_validator_count(prev_epoch)
+    {
+        set_gauge_by_usize(&ATTN_OBSERVATION_PREV_EPOCH_AGGREGATORS, count);
+    }
+}
+
 fn set_gauge_by_slot(gauge: &Result<IntGauge>, value: Slot) {
     set_gauge(gauge, value.as_u64() as i64);
 }

beacon_node/beacon_chain/src/naive_aggregation_pool.rs

@@ -1,3 +1,4 @@
+use crate::metrics;
 use parking_lot::RwLock;
 use std::collections::HashMap;
 use types::{Attestation, AttestationData, EthSpec, Slot};
@@ -68,6 +69,8 @@ impl<E: EthSpec> AggregatedAttestationMap<E> {
     ///
     /// The given attestation (`a`) must only have one signature.
     pub fn insert(&mut self, a: &Attestation<E>) -> Result<InsertOutcome, Error> {
+        let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_AGG_POOL_CORE_INSERT);
+
         let set_bits = a
             .aggregation_bits
             .iter()
@@ -93,6 +96,8 @@ impl<E: EthSpec> AggregatedAttestationMap<E> {
             {
                 Ok(InsertOutcome::SignatureAlreadyKnown { committee_index })
             } else {
+                let _timer =
+                    metrics::start_timer(&metrics::ATTESTATION_PROCESSING_AGG_POOL_AGGREGATION);
                 existing_attestation.aggregate(a);
                 Ok(InsertOutcome::SignatureAggregated { committee_index })
             }
@@ -164,8 +169,9 @@ impl<E: EthSpec> NaiveAggregationPool<E> {
     /// The pool may be pruned if the given `attestation.data` has a slot higher than any
     /// previously seen.
     pub fn insert(&self, attestation: &Attestation<E>) -> Result<InsertOutcome, Error> {
+        let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_AGG_POOL_INSERT);
         let slot = attestation.data.slot;
-        let lowest_permissible_slot = *self.lowest_permissible_slot.read();
+        let lowest_permissible_slot: Slot = *self.lowest_permissible_slot.read();
 
         // Reject any attestations that are too old.
         if slot < lowest_permissible_slot {
@@ -175,11 +181,15 @@ impl<E: EthSpec> NaiveAggregationPool<E> {
             });
         }
 
+        let lock_timer =
+            metrics::start_timer(&metrics::ATTESTATION_PROCESSING_AGG_POOL_MAPS_WRITE_LOCK);
         let mut maps = self.maps.write();
+        drop(lock_timer);
 
         let outcome = if let Some(map) = maps.get_mut(&slot) {
             map.insert(attestation)
         } else {
+            let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_AGG_POOL_CREATE_MAP);
             // To avoid re-allocations, try and determine a rough initial capacity for the new item
             // by obtaining the mean size of all items in earlier epoch.
             let (count, sum) = maps
@@ -219,8 +229,19 @@ impl<E: EthSpec> NaiveAggregationPool<E> {
     /// Removes any attestations with a slot lower than `current_slot` and bars any future
     /// attestations with a slot lower than `current_slot - SLOTS_RETAINED`.
     pub fn prune(&self, current_slot: Slot) {
+        let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_AGG_POOL_PRUNE);
+
         // Taking advantage of saturating subtraction on `Slot`.
         let lowest_permissible_slot = current_slot - Slot::from(SLOTS_RETAINED);
+
+        // No need to prune if the lowest permissible slot has not changed and the queue length is
+        // less than the maximum
+        if *self.lowest_permissible_slot.read() == lowest_permissible_slot
+            && self.maps.read().len() <= SLOTS_RETAINED
+        {
+            return;
+        }
+
         *self.lowest_permissible_slot.write() = lowest_permissible_slot;
         let mut maps = self.maps.write();
 

beacon_node/beacon_chain/src/observed_attesters.rs

@@ -36,9 +36,12 @@ pub trait Item {
     /// The default capacity for self. Used when we can't guess a reasonable size.
     fn default_capacity() -> usize;
 
-    /// Returns the number of validator indices stored in `self`.
+    /// Returns the allocated size of `self`, measured by validator indices.
     fn len(&self) -> usize;
 
+    /// Returns the number of validators that have been observed by `self`.
+    fn validator_count(&self) -> usize;
+
     /// Store `validator_index` in `self`.
     fn insert(&mut self, validator_index: usize) -> bool;
 
@@ -67,6 +70,10 @@ impl Item for EpochBitfield {
         self.bitfield.len()
     }
 
+    fn validator_count(&self) -> usize {
+        self.bitfield.iter().filter(|bit| **bit).count()
+    }
+
     fn insert(&mut self, validator_index: usize) -> bool {
         self.bitfield
             .get_mut(validator_index)
@@ -116,6 +123,10 @@ impl Item for EpochHashSet {
         self.set.len()
     }
 
+    fn validator_count(&self) -> usize {
+        self.set.len()
+    }
+
     /// Inserts the `validator_index` in the set. Returns `true` if the `validator_index` was
     /// already in the set.
     fn insert(&mut self, validator_index: usize) -> bool {
@@ -219,6 +230,15 @@ impl<T: Item, E: EthSpec> AutoPruningContainer<T, E> {
         Ok(exists)
     }
 
+    /// Returns the number of validators that have been observed at the given `epoch`. Returns
+    /// `None` if `self` does not have a cache for that epoch.
+    pub fn observed_validator_count(&self, epoch: Epoch) -> Option<usize> {
+        self.items
+            .read()
+            .get(&epoch)
+            .map(|item| item.validator_count())
+    }
+
     fn sanitize_request(&self, a: &Attestation<E>, validator_index: usize) -> Result<(), Error> {
         if validator_index > E::ValidatorRegistryLimit::to_usize() {
             return Err(Error::ValidatorIndexTooHigh(validator_index));