From fd0852a8e59be905824cebfb4f2fe028a920159b Mon Sep 17 00:00:00 2001 From: Michael Sproul Date: Tue, 19 May 2026 11:35:31 +1000 Subject: [PATCH 1/2] Remove outdated SPRP hint (#9312) While working on this code in another branch I noticed we had this messy, complicated and incorrect code about SPRP (slots-per-restore-point), which is no longer a relevant concept since the introduction of hot state diffs. In the name of simplicity, I've removed any kind of hinting here in favour of a simple out of bounds error. The benefit of adding complex hinting code (which is not tested) to such a function is not worth it IMO. Users will work it out (or ask) if we just tell them their request is out of bounds. Co-Authored-By: Michael Sproul --- beacon_node/http_api/src/beacon/states.rs | 74 +++++++++-------------- 1 file changed, 27 insertions(+), 47 deletions(-) diff --git a/beacon_node/http_api/src/beacon/states.rs b/beacon_node/http_api/src/beacon/states.rs index 84ef3c1f26..52b05a807b 100644 --- a/beacon_node/http_api/src/beacon/states.rs +++ b/beacon_node/http_api/src/beacon/states.rs @@ -390,54 +390,34 @@ pub fn get_beacon_state_committees( if let Some(shuffling) = maybe_cached_shuffling { shuffling } else { - let possibly_built_cache = - match RelativeEpoch::from_epoch(current_epoch, epoch) { - Ok(relative_epoch) - if state.committee_cache_is_initialized( - relative_epoch, - ) => - { - state.committee_cache(relative_epoch).cloned() - } - _ => CommitteeCache::initialized( - state, - epoch, - &chain.spec, - ), + let possibly_built_cache = match RelativeEpoch::from_epoch( + current_epoch, + epoch, + ) { + Ok(relative_epoch) + if state.committee_cache_is_initialized( + relative_epoch, + ) => + { + state.committee_cache(relative_epoch).cloned() } - .map_err( - |e| match e { - BeaconStateError::EpochOutOfBounds => { - let max_sprp = - T::EthSpec::slots_per_historical_root() - as u64; - let first_subsequent_restore_point_slot = - ((epoch.start_slot( - T::EthSpec::slots_per_epoch(), - ) / max_sprp) - + 1) - * max_sprp; - if epoch < current_epoch { - warp_utils::reject::custom_bad_request( - format!( - "epoch out of bounds, \ - try state at slot {}", - first_subsequent_restore_point_slot, - ), - ) - } else { - warp_utils::reject::custom_bad_request( - "epoch out of bounds, \ - too far in future" - .into(), - ) - } - } - _ => warp_utils::reject::unhandled_error( - BeaconChainError::from(e), - ), - }, - )?; + _ => CommitteeCache::initialized( + state, + epoch, + &chain.spec, + ), + } + .map_err(|e| match e { + BeaconStateError::EpochOutOfBounds => { + warp_utils::reject::custom_bad_request(format!( + "epoch {} out of bounds for state at {}", + epoch, current_epoch + )) + } + _ => warp_utils::reject::unhandled_error( + BeaconChainError::from(e), + ), + })?; // Attempt to write to the beacon cache (only if the cache // size is not the default value). From 398efc3acca5c8d01befbbe09d35d24cbd04752c Mon Sep 17 00:00:00 2001 From: Lion - dapplion <35266934+dapplion@users.noreply.github.com> Date: Mon, 18 May 2026 23:12:17 -0600 Subject: [PATCH 2/2] Use dedicated cache for HTTP API route (#9318) - PR https://github.com/sigp/lighthouse/pull/9305 wants to store PTCs in the committee cache. BUT the http API route wants to use the committee cache and insert historical committees (i.e. given state at epoch 1000, compute and store the committee for epoch 900). If we want a single cache to serve both use cases we need to: - Have entries in the committee cache that have no PTC: Makes reading PTCs from the cache not deterministic - Compute historical PTC: A bunch of complicated code that's useless Instead we can add a separate cache for the API, very simple one, that caches committees only. And have the one in the beacon chain compute and cache PTCs always. ### Performance impact Slightly additional memory cost for users of the `beacon/states/committees` route. Caching is almost equivalent, except for queries of recent committees that may already exist in the beacon chain's committee cache. ### AI disclousure This PR was written by hand 90%. Claude fixed some warp type issues Co-Authored-By: dapplion <35266934+dapplion@users.noreply.github.com> --- beacon_node/client/src/builder.rs | 5 ++ beacon_node/http_api/src/beacon/states.rs | 81 ++++++++++++----------- beacon_node/http_api/src/caches.rs | 43 ++++++++++++ beacon_node/http_api/src/lib.rs | 17 ++++- beacon_node/http_api/src/test_utils.rs | 7 +- beacon_node/src/config.rs | 3 + 6 files changed, 115 insertions(+), 41 deletions(-) create mode 100644 beacon_node/http_api/src/caches.rs diff --git a/beacon_node/client/src/builder.rs b/beacon_node/client/src/builder.rs index 9dfb8304bc..f532ef716e 100644 --- a/beacon_node/client/src/builder.rs +++ b/beacon_node/client/src/builder.rs @@ -36,6 +36,7 @@ use rand::SeedableRng; use rand::rngs::{OsRng, StdRng}; use slasher::Slasher; use slasher_service::SlasherService; +use std::num::NonZeroUsize; use std::path::{Path, PathBuf}; use std::sync::Arc; use std::time::Duration; @@ -639,6 +640,10 @@ where network_globals: self.network_globals.clone(), beacon_processor_send: Some(beacon_processor_channels.beacon_processor_tx.clone()), sse_logging_components: runtime_context.sse_logging_components.clone(), + historical_committee_cache: Arc::new(http_api::HistoricalCommitteeCache::new( + NonZeroUsize::new(self.http_api_config.historical_committee_cache_size) + .unwrap_or(NonZeroUsize::MIN), + )), }); let exit = runtime_context.executor.exit(); diff --git a/beacon_node/http_api/src/beacon/states.rs b/beacon_node/http_api/src/beacon/states.rs index 52b05a807b..1b765aa227 100644 --- a/beacon_node/http_api/src/beacon/states.rs +++ b/beacon_node/http_api/src/beacon/states.rs @@ -1,4 +1,5 @@ use crate::StateId; +use crate::caches::{HistoricalCommitteeCache, HistoricalShufflingId}; use crate::task_spawner::{Priority, TaskSpawner}; use crate::utils::ResponseFilter; use crate::validator::pubkey_to_validator_index; @@ -13,7 +14,10 @@ use eth2::types::{ }; use ssz::Encode; use std::sync::Arc; -use types::{AttestationShufflingId, BeaconStateError, CommitteeCache, EthSpec, RelativeEpoch}; +use types::{ + AttestationShufflingId, BeaconStateError, CommitteeCache, EthSpec, RelativeEpoch, + RelativeEpochError, +}; use warp::filters::BoxedFilter; use warp::http::Response; use warp::hyper::Body; @@ -26,6 +30,8 @@ type BeaconStatesPath = BoxedFilter<( Arc>, )>; +type BeaconStatesCommitteesFilter = BoxedFilter<(Arc,)>; + // GET beacon/states/{state_id}/pending_consolidations pub fn get_beacon_state_pending_consolidations( beacon_states_path: BeaconStatesPath, @@ -337,17 +343,20 @@ pub fn get_beacon_state_sync_committees( // GET beacon/states/{state_id}/committees?slot,index,epoch pub fn get_beacon_state_committees( beacon_states_path: BeaconStatesPath, + beacon_states_committees_filter: BeaconStatesCommitteesFilter, ) -> ResponseFilter { beacon_states_path .clone() .and(warp::path("committees")) .and(warp::query::()) + .and(beacon_states_committees_filter) .and(warp::path::end()) .then( |state_id: StateId, task_spawner: TaskSpawner, chain: Arc>, - query: eth2::types::CommitteesQuery| { + query: eth2::types::CommitteesQuery, + historical_committee_cache: Arc| { task_spawner.blocking_json_task(Priority::P1, move || { let (data, execution_optimistic, finalized) = state_id .map_state_and_execution_optimistic_and_finalized( @@ -364,33 +373,33 @@ pub fn get_beacon_state_committees( let shuffling_id = if let Ok(Some(shuffling_decision_block)) = chain.block_root_at_slot(decision_slot, WhenSlotSkipped::Prev) { - Some(AttestationShufflingId { - shuffling_epoch: epoch, - shuffling_decision_block, - }) + Some(HistoricalShufflingId::ShufflingId( + AttestationShufflingId { + shuffling_epoch: epoch, + shuffling_decision_block, + }, + )) + } else if epoch < chain.head().finalized_checkpoint().epoch { + // Use the case for finalized epochs + Some(HistoricalShufflingId::FinalizedEpoch(epoch)) } else { None }; // Attempt to read from the chain cache if there exists a // shuffling_id - let maybe_cached_shuffling = if let Some(shuffling_id) = - shuffling_id.as_ref() - { - chain - .shuffling_cache - .try_write_for(std::time::Duration::from_secs(1)) - .and_then(|mut cache_write| cache_write.get(shuffling_id)) - .and_then(|cache_item| cache_item.wait().ok()) - } else { - None - }; + let maybe_cached_shuffling = + if let Some(shuffling_id) = shuffling_id.as_ref() { + historical_committee_cache.get(shuffling_id) + } else { + None + }; let committee_cache = if let Some(shuffling) = maybe_cached_shuffling { shuffling } else { - let possibly_built_cache = match RelativeEpoch::from_epoch( + let committee_cache = match RelativeEpoch::from_epoch( current_epoch, epoch, ) { @@ -401,11 +410,19 @@ pub fn get_beacon_state_committees( { state.committee_cache(relative_epoch).cloned() } - _ => CommitteeCache::initialized( - state, - epoch, - &chain.spec, - ), + Ok(_) | Err(RelativeEpochError::EpochTooLow { .. }) => { + CommitteeCache::initialized( + state, + epoch, + &chain.spec, + ) + } + Err(RelativeEpochError::EpochTooHigh { .. }) => { + Err(BeaconStateError::EpochOutOfBounds) + } + Err(RelativeEpochError::ArithError(e)) => { + Err(BeaconStateError::ArithError(e)) + } } .map_err(|e| match e { BeaconStateError::EpochOutOfBounds => { @@ -419,22 +436,12 @@ pub fn get_beacon_state_committees( ), })?; - // Attempt to write to the beacon cache (only if the cache - // size is not the default value). - if chain.config.shuffling_cache_size - != beacon_chain::shuffling_cache::DEFAULT_CACHE_SIZE - && let Some(shuffling_id) = shuffling_id - && let Some(mut cache_write) = chain - .shuffling_cache - .try_write_for(std::time::Duration::from_secs(1)) - { - cache_write.insert_committee_cache( - shuffling_id, - &possibly_built_cache, - ); + if let Some(shuffling_id) = shuffling_id { + historical_committee_cache + .insert(shuffling_id, committee_cache.clone()); } - possibly_built_cache + committee_cache }; // Use either the supplied slot or all slots in the epoch. diff --git a/beacon_node/http_api/src/caches.rs b/beacon_node/http_api/src/caches.rs new file mode 100644 index 0000000000..d92571594a --- /dev/null +++ b/beacon_node/http_api/src/caches.rs @@ -0,0 +1,43 @@ +use lru::LruCache; +use parking_lot::Mutex; +use std::num::NonZeroUsize; +use std::sync::Arc; +use types::{AttestationShufflingId, CommitteeCache, Epoch}; + +/// See `shuffling_cache::DEFAULT_CACHE_SIZE` for rationale +pub const DEFAULT_HISTORICAL_COMMITTEE_CACHE_SIZE: usize = 16; + +/// Indexes the `HistoricalCommitteeCache`. We can compute committees for very old epochs, and we +/// can't retrieve the decision root cheaply from a state. For those cases we allow the cache to +/// key those committees by finalized epoch. +#[derive(Eq, Hash, PartialEq)] +pub enum HistoricalShufflingId { + FinalizedEpoch(Epoch), + ShufflingId(AttestationShufflingId), +} + +/// Dedicated cache for attestation committees, used exclusively by the HTTP API. +/// +/// This may contain committees for finalized and unfinalized epochs. The name is slightly +/// missleading :) +pub struct HistoricalCommitteeCache { + committees: Mutex>>, +} + +impl HistoricalCommitteeCache { + pub fn new(size: NonZeroUsize) -> Self { + Self { + committees: Mutex::new(LruCache::new(size)), + } + } +} + +impl HistoricalCommitteeCache { + pub fn get(&self, id: &HistoricalShufflingId) -> Option> { + self.committees.lock().get(id).cloned() + } + + pub fn insert(&self, id: HistoricalShufflingId, cache: Arc) { + self.committees.lock().put(id, cache); + } +} diff --git a/beacon_node/http_api/src/lib.rs b/beacon_node/http_api/src/lib.rs index f31817c5ba..74bf1ccd76 100644 --- a/beacon_node/http_api/src/lib.rs +++ b/beacon_node/http_api/src/lib.rs @@ -12,6 +12,7 @@ mod beacon; mod block_id; mod build_block_contents; mod builder_states; +mod caches; mod custody; mod database; mod light_client; @@ -40,6 +41,8 @@ use crate::beacon::execution_payload_envelope::{ post_beacon_execution_payload_envelope_ssz, }; use crate::beacon::pool::*; +use crate::caches::DEFAULT_HISTORICAL_COMMITTEE_CACHE_SIZE; +pub use crate::caches::HistoricalCommitteeCache; use crate::light_client::{get_light_client_bootstrap, get_light_client_updates}; use crate::utils::{AnyVersionFilter, EthV1Filter}; use crate::validator::post_validator_liveness_epoch; @@ -132,6 +135,7 @@ pub struct Context { pub network_globals: Option>>, pub beacon_processor_send: Option>, pub sse_logging_components: Option, + pub historical_committee_cache: Arc, } /// Configuration for the HTTP server. @@ -148,6 +152,7 @@ pub struct Config { #[serde(with = "eth2::types::serde_status_code")] pub duplicate_block_status_code: StatusCode, pub target_peers: usize, + pub historical_committee_cache_size: usize, } impl Default for Config { @@ -163,6 +168,7 @@ impl Default for Config { enable_beacon_processor: true, duplicate_block_status_code: StatusCode::ACCEPTED, target_peers: 100, + historical_committee_cache_size: DEFAULT_HISTORICAL_COMMITTEE_CACHE_SIZE, } } } @@ -416,6 +422,11 @@ pub fn serve( }) .boxed(); + let historical_committee_cache = ctx.historical_committee_cache.clone(); + let beacon_states_committees_filter = warp::any() + .map(move || historical_committee_cache.clone()) + .boxed(); + // Create a `warp` filter that provides access to the network sender channel. let network_tx = ctx .network_senders @@ -628,8 +639,10 @@ pub fn serve( states::get_beacon_state_validators_id(beacon_states_path.clone()); // GET beacon/states/{state_id}/committees?slot,index,epoch - let get_beacon_state_committees = - states::get_beacon_state_committees(beacon_states_path.clone()); + let get_beacon_state_committees = states::get_beacon_state_committees( + beacon_states_path.clone(), + beacon_states_committees_filter, + ); // GET beacon/states/{state_id}/sync_committees?epoch let get_beacon_state_sync_committees = diff --git a/beacon_node/http_api/src/test_utils.rs b/beacon_node/http_api/src/test_utils.rs index 27e2a27d35..f27a04d17a 100644 --- a/beacon_node/http_api/src/test_utils.rs +++ b/beacon_node/http_api/src/test_utils.rs @@ -1,4 +1,4 @@ -use crate::{Config, Context}; +use crate::{Config, Context, caches::HistoricalCommitteeCache}; use beacon_chain::{ BeaconChain, BeaconChainTypes, custody_context::NodeCustodyType, @@ -22,10 +22,10 @@ use lighthouse_network::{ }; use network::{NetworkReceivers, NetworkSenders}; use sensitive_url::SensitiveUrl; -use std::future::Future; use std::net::SocketAddr; use std::sync::Arc; use std::time::Duration; +use std::{future::Future, num::NonZeroUsize}; use store::MemoryStore; use task_executor::test_utils::TestRuntime; use types::{ChainSpec, EthSpec}; @@ -293,6 +293,9 @@ pub async fn create_api_server_with_config( network_globals: Some(network_globals), beacon_processor_send: Some(beacon_processor_send), sse_logging_components: None, + historical_committee_cache: Arc::new(HistoricalCommitteeCache::new( + NonZeroUsize::new(http_config.historical_committee_cache_size).unwrap(), + )), }); let (listening_socket, server) = diff --git a/beacon_node/src/config.rs b/beacon_node/src/config.rs index 8ba2c0f321..f10f9e3b45 100644 --- a/beacon_node/src/config.rs +++ b/beacon_node/src/config.rs @@ -215,6 +215,9 @@ pub fn get_config( if let Some(cache_size) = clap_utils::parse_optional(cli_args, "shuffling-cache-size")? { client_config.chain.shuffling_cache_size = cache_size; + // Mantain backwards compatibility with users customizing `shuffling_cache_size` to tweak + // the behaviour of the HTTP API route `beacon/states/committees` + client_config.http_api.historical_committee_cache_size = cache_size; } if let Some(batches) = clap_utils::parse_optional(cli_args, "blob-publication-batches")? {