From 48aa32bece9ed1bfbd0001262a8b0d1ea47876e4 Mon Sep 17 00:00:00 2001
From: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>
Date: Sat, 22 Jun 2019 12:21:29 -0400
Subject: [PATCH] Relative slots (#2820)
MIME-Version: 1.0
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* Initial work on relative slots for BABE
* More work
* Update core/consensus/babe/src/lib.rs
`Aura` → `Babe`
Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>
* More work on relative slots
* Add missing field in test-runtime
* Bump `impl_version` and `authoring_version`
* Fix compile errors and warnings
* Upgrade dependencies
* Update dependencies more
* Revert some updates to dependencies
Somehow, those broke the build
* Fix compilation errors
* `Duration` → `u128` in calculations
* `slot_duration` is in milleseconds, not seconds
* Median algorithm: ignore blocks with slot_num < sl
* Fix silly compile error
* Store a duration, rather than an instant
It is more useful
* Fix compilation errors
* `INVERSE_NANO` → `NANOS_PER_SEC`
Also: `1000_000_000` → `1_000_000_000`
Suggested-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>
* Un-bump `authoring_version`
* Disable median algorithm when `median_required_blocks` is 0
Otherwise it would panic.
* Apply suggestions from code review
Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>
* Simplify panic
* Fix build error
* Create `SignedDuration` struct
for signed `Duration` values.
Suggested-by: Bastian Köcher
* Refactor median algorithm into separate function
* Add issues for FIXMEs and respond to code review
* Fix minor warnings
---
substrate/core/client/db/src/utils.rs | 1 -
substrate/core/consensus/aura/src/lib.rs | 7 +-
.../core/consensus/babe/primitives/src/lib.rs | 9 ++
substrate/core/consensus/babe/src/lib.rs | 130 ++++++++++++++++--
substrate/core/consensus/slots/src/lib.rs | 2 +-
substrate/core/consensus/slots/src/slots.rs | 49 ++++---
substrate/core/network/src/test/mod.rs | 2 +-
substrate/core/test-runtime/src/lib.rs | 2 +
8 files changed, 167 insertions(+), 35 deletions(-)
diff --git a/substrate/core/client/db/src/utils.rs b/substrate/core/client/db/src/utils.rs
index a0b955a1a2f..a4ab82b5d8b 100644
--- a/substrate/core/client/db/src/utils.rs
+++ b/substrate/core/client/db/src/utils.rs
@@ -189,7 +189,6 @@ pub fn block_id_to_lookup_key<Block>(
/// Maps database error to client error
pub fn db_err(err: io::Error) -> client::error::Error {
- use std::error::Error;
client::error::Error::Backend(format!("{}", err))
}
diff --git a/substrate/core/consensus/aura/src/lib.rs b/substrate/core/consensus/aura/src/lib.rs
index 896b2d4b00d..c85e273a42b 100644
--- a/substrate/core/consensus/aura/src/lib.rs
+++ b/substrate/core/consensus/aura/src/lib.rs
@@ -63,7 +63,8 @@ use srml_aura::{
};
use substrate_telemetry::{telemetry, CONSENSUS_TRACE, CONSENSUS_DEBUG, CONSENSUS_WARN, CONSENSUS_INFO};
-use slots::{CheckedHeader, SlotData, SlotWorker, SlotInfo, SlotCompatible, slot_now, check_equivocation};
+use slots::{CheckedHeader, SlotData, SlotWorker, SlotInfo, SlotCompatible};
+use slots::{SignedDuration, check_equivocation};
pub use aura_primitives::*;
pub use consensus_common::SyncOracle;
@@ -283,8 +284,8 @@ impl<H, B, C, E, I, P, Error, SO> SlotWorker<B> for AuraWorker<C, E, I, P, SO> w
Box::new(proposal_work.map(move |b| {
// minor hack since we don't have access to the timestamp
// that is actually set by the proposer.
- let slot_after_building = slot_now(slot_duration);
- if slot_after_building != Some(slot_num) {
+ let slot_after_building = SignedDuration::default().slot_now(slot_duration);
+ if slot_after_building != slot_num {
info!(
"Discarding proposal for slot {}; block production took too long",
slot_num
diff --git a/substrate/core/consensus/babe/primitives/src/lib.rs b/substrate/core/consensus/babe/primitives/src/lib.rs
index cd056544e6a..f1d4a452d68 100644
--- a/substrate/core/consensus/babe/primitives/src/lib.rs
+++ b/substrate/core/consensus/babe/primitives/src/lib.rs
@@ -51,6 +51,15 @@ pub struct BabeConfiguration {
///
/// Dynamic thresholds may be supported in the future.
pub threshold: u64,
+
+ /// The minimum number of blocks that must be received before running the
+ /// median algorithm to compute the offset between the on-chain time and the
+ /// local time. Currently, only the value provided by this type at genesis
+ /// will be used, but this is subject to change.
+ ///
+ /// Blocks less than `self.median_required_blocks` must be generated by an
+ /// *initial validator* ― that is, a node that was a validator at genesis.
+ pub median_required_blocks: u64,
}
#[cfg(feature = "std")]
diff --git a/substrate/core/consensus/babe/src/lib.rs b/substrate/core/consensus/babe/src/lib.rs
index 3e1f38077f8..0bab790c991 100644
--- a/substrate/core/consensus/babe/src/lib.rs
+++ b/substrate/core/consensus/babe/src/lib.rs
@@ -30,15 +30,20 @@ use digest::CompatibleDigestItem;
pub use digest::{BabePreDigest, BABE_VRF_PREFIX};
pub use babe_primitives::*;
pub use consensus_common::SyncOracle;
+use consensus_common::import_queue::{
+ SharedBlockImport, SharedJustificationImport, SharedFinalityProofImport,
+ SharedFinalityProofRequestBuilder,
+};
use consensus_common::well_known_cache_keys::Id as CacheKeyId;
use runtime_primitives::{generic, generic::{BlockId, OpaqueDigestItemId}, Justification};
use runtime_primitives::traits::{
Block, Header, DigestItemFor, ProvideRuntimeApi,
- SimpleBitOps,
+ SimpleBitOps, Zero,
};
-use std::{sync::Arc, u64, fmt::{Debug, Display}};
+use std::{sync::Arc, u64, fmt::{Debug, Display}, time::{Instant, Duration}};
use runtime_support::serde::{Serialize, Deserialize};
use parity_codec::{Decode, Encode};
+use parking_lot::Mutex;
use primitives::{crypto::Pair, sr25519};
use merlin::Transcript;
use inherents::{InherentDataProviders, InherentData};
@@ -77,7 +82,7 @@ use futures::{Future, IntoFuture, future};
use tokio_timer::Timeout;
use log::{error, warn, debug, info, trace};
-use slots::{SlotWorker, SlotData, SlotInfo, SlotCompatible, slot_now};
+use slots::{SlotWorker, SlotData, SlotInfo, SlotCompatible, SignedDuration};
pub use babe_primitives::AuthorityId;
@@ -332,8 +337,8 @@ impl<Hash, H, B, C, E, I, Error, SO> SlotWorker<B> for BabeWorker<C, E, I, SO> w
Box::new(proposal_work.map(move |b| {
// minor hack since we don't have access to the timestamp
// that is actually set by the proposer.
- let slot_after_building = slot_now(slot_duration);
- if slot_after_building != Some(slot_num) {
+ let slot_after_building = SignedDuration::default().slot_now(slot_duration);
+ if slot_after_building != slot_num {
info!(
target: "babe",
"Discarding proposal for slot {}; block production took too long",
@@ -512,7 +517,8 @@ fn check_header<B: Block + Sized, C: AuxStore>(
pub struct BabeVerifier<C> {
client: Arc<C>,
inherent_data_providers: inherents::InherentDataProviders,
- threshold: u64,
+ config: Config,
+ timestamps: Mutex<(Option<Duration>, Vec<(Instant, u64)>)>,
}
impl<C> BabeVerifier<C> {
@@ -540,6 +546,38 @@ impl<C> BabeVerifier<C> {
}
}
+fn median_algorithm(
+ median_required_blocks: u64,
+ slot_duration: u64,
+ slot_num: u64,
+ slot_now: u64,
+ timestamps: &mut (Option<Duration>, Vec<(Instant, u64)>),
+) {
+ let num_timestamps = timestamps.1.len();
+ if num_timestamps as u64 >= median_required_blocks && median_required_blocks > 0 {
+ let mut new_list: Vec<_> = timestamps.1.iter().map(|&(t, sl)| {
+ let offset: u128 = u128::from(slot_duration)
+ .checked_mul(1_000_000u128) // self.config.get() returns *milliseconds*
+ .and_then(|x| x.checked_mul(u128::from(slot_num).saturating_sub(u128::from(sl))))
+ .expect("we cannot have timespans long enough for this to overflow; qed");
+ const NANOS_PER_SEC: u32 = 1_000_000_000;
+ let nanos = (offset % u128::from(NANOS_PER_SEC)) as u32;
+ let secs = (offset / u128::from(NANOS_PER_SEC)) as u64;
+ t + Duration::new(secs, nanos)
+ }).collect();
+ // FIXME #2926: use a selection algorithm instead of a full sorting algorithm.
+ new_list.sort_unstable();
+ let &median = new_list
+ .get(num_timestamps / 2)
+ .expect("we have at least one timestamp, so this is a valid index; qed");
+ timestamps.1.clear();
+ // FIXME #2927: pass this to the block authoring logic somehow
+ timestamps.0.replace(Instant::now() - median);
+ } else {
+ timestamps.1.push((Instant::now(), slot_now))
+ }
+}
+
impl<B: Block, C> Verifier<B> for BabeVerifier<C> where
C: ProvideRuntimeApi + Send + Sync + AuxStore + ProvideCache<B>,
C::Api: BlockBuilderApi<B> + BabeApi<B>,
@@ -582,7 +620,7 @@ impl<B: Block, C> Verifier<B> for BabeVerifier<C> where
header,
hash,
&authorities[..],
- self.threshold,
+ self.config.threshold(),
)?;
match checked_header {
CheckedHeader::Checked(pre_header, (pre_digest, seal)) => {
@@ -629,7 +667,13 @@ impl<B: Block, C> Verifier<B> for BabeVerifier<C> where
auxiliary: Vec::new(),
fork_choice: ForkChoiceStrategy::LongestChain,
};
-
+ median_algorithm(
+ self.config.0.median_required_blocks,
+ self.config.get(),
+ slot_num,
+ slot_now,
+ &mut *self.timestamps.lock(),
+ );
// FIXME #1019 extract authorities
Ok((import_block, maybe_keys))
}
@@ -739,6 +783,72 @@ fn claim_slot(
get_keypair(key).vrf_sign_n_check(transcript, |inout| check(inout, threshold))
}
+fn initialize_authorities_cache<B, C>(client: &C) -> Result<(), ConsensusError> where
+ B: Block,
+ C: ProvideRuntimeApi + ProvideCache<B>,
+ C::Api: BabeApi<B>,
+{
+ // no cache => no initialization
+ let cache = match client.cache() {
+ Some(cache) => cache,
+ None => return Ok(()),
+ };
+
+ // check if we already have initialized the cache
+ let genesis_id = BlockId::Number(Zero::zero());
+ let genesis_authorities: Option<Vec<AuthorityId>> = cache
+ .get_at(&well_known_cache_keys::AUTHORITIES, &genesis_id)
+ .and_then(|v| Decode::decode(&mut &v[..]));
+ if genesis_authorities.is_some() {
+ return Ok(());
+ }
+
+ let map_err = |error| consensus_common::Error::from(consensus_common::Error::ClientImport(
+ format!(
+ "Error initializing authorities cache: {}",
+ error,
+ )));
+ let genesis_authorities = authorities(client, &genesis_id)?;
+ cache.initialize(&well_known_cache_keys::AUTHORITIES, genesis_authorities.encode())
+ .map_err(map_err)
+}
+
+/// Start an import queue for the Babe consensus algorithm.
+pub fn import_queue<B, C, E>(
+ config: Config,
+ block_import: SharedBlockImport<B>,
+ justification_import: Option<SharedJustificationImport<B>>,
+ finality_proof_import: Option<SharedFinalityProofImport<B>>,
+ finality_proof_request_builder: Option<SharedFinalityProofRequestBuilder<B>>,
+ client: Arc<C>,
+ inherent_data_providers: InherentDataProviders,
+) -> Result<BabeImportQueue<B>, consensus_common::Error> where
+ B: Block,
+ C: 'static + ProvideRuntimeApi + ProvideCache<B> + Send + Sync + AuxStore,
+ C::Api: BlockBuilderApi<B> + BabeApi<B>,
+ DigestItemFor<B>: CompatibleDigestItem,
+ E: 'static,
+{
+ register_babe_inherent_data_provider(&inherent_data_providers, config.get())?;
+ initialize_authorities_cache(&*client)?;
+
+ let verifier = Arc::new(
+ BabeVerifier {
+ client: client,
+ inherent_data_providers,
+ timestamps: Default::default(),
+ config,
+ }
+ );
+ Ok(BasicQueue::new(
+ verifier,
+ block_import,
+ justification_import,
+ finality_proof_import,
+ finality_proof_request_builder,
+ ))
+}
+
#[cfg(test)]
#[allow(dead_code, unused_imports, deprecated)]
// FIXME #2532: need to allow deprecated until refactor is done
@@ -753,7 +863,6 @@ mod tests {
use network::test::{Block as TestBlock, PeersClient};
use runtime_primitives::traits::{Block as BlockT, DigestFor};
use network::config::ProtocolConfig;
- use parking_lot::Mutex;
use tokio::runtime::current_thread;
use keyring::sr25519::Keyring;
use super::generic::DigestItem;
@@ -837,7 +946,8 @@ mod tests {
Arc::new(BabeVerifier {
client,
inherent_data_providers,
- threshold: config.threshold(),
+ config,
+ timestamps: Default::default(),
})
}
diff --git a/substrate/core/consensus/slots/src/lib.rs b/substrate/core/consensus/slots/src/lib.rs
index 18ec2451beb..c26b6e2ff6c 100644
--- a/substrate/core/consensus/slots/src/lib.rs
+++ b/substrate/core/consensus/slots/src/lib.rs
@@ -25,7 +25,7 @@
mod slots;
mod aux_schema;
-pub use slots::{slot_now, SlotInfo, Slots};
+pub use slots::{SignedDuration, SlotInfo, Slots};
pub use aux_schema::{check_equivocation, MAX_SLOT_CAPACITY, PRUNING_BOUND};
use codec::{Decode, Encode};
diff --git a/substrate/core/consensus/slots/src/slots.rs b/substrate/core/consensus/slots/src/slots.rs
index a848a967629..1bce98487ac 100644
--- a/substrate/core/consensus/slots/src/slots.rs
+++ b/substrate/core/consensus/slots/src/slots.rs
@@ -23,29 +23,44 @@ use consensus_common::Error;
use futures::prelude::*;
use futures::try_ready;
use inherents::{InherentData, InherentDataProviders};
-use log::warn;
+
use std::marker::PhantomData;
use std::time::{Duration, Instant};
use tokio_timer::Delay;
/// Returns current duration since unix epoch.
-pub fn duration_now() -> Option<Duration> {
+pub fn duration_now() -> Duration {
use std::time::SystemTime;
-
let now = SystemTime::now();
- now.duration_since(SystemTime::UNIX_EPOCH)
- .map_err(|e| {
- warn!(
- "Current time {:?} is before unix epoch. Something is wrong: {:?}",
- now, e
- );
- })
- .ok()
+ now.duration_since(SystemTime::UNIX_EPOCH).unwrap_or_else(|e| panic!(
+ "Current time {:?} is before unix epoch. Something is wrong: {:?}",
+ now,
+ e,
+ ))
+}
+
+
+/// A `Duration` with a sign (before or after). Immutable.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+pub struct SignedDuration {
+ offset: Duration,
+ is_positive: bool,
}
-/// Get the slot for now.
-pub fn slot_now(slot_duration: u64) -> Option<u64> {
- duration_now().map(|s| s.as_secs() / slot_duration)
+impl SignedDuration {
+ /// Construct a `SignedDuration`
+ pub fn new(offset: Duration, is_positive: bool) -> Self {
+ Self { offset, is_positive }
+ }
+
+ /// Get the slot for now. Panics if `slot_duration` is 0.
+ pub fn slot_now(&self, slot_duration: u64) -> u64 {
+ if self.is_positive {
+ duration_now() + self.offset
+ } else {
+ duration_now() - self.offset
+ }.as_secs() / slot_duration
+ }
}
/// Returns the duration until the next slot, based on current duration since
@@ -112,11 +127,7 @@ impl<SC: SlotCompatible> Stream for Slots<SC> {
self.inner_delay = match self.inner_delay.take() {
None => {
// schedule wait.
- let wait_until = match duration_now() {
- None => return Ok(Async::Ready(None)),
- Some(now) => Instant::now() + time_until_next(now, slot_duration),
- };
-
+ let wait_until = Instant::now() + time_until_next(duration_now(), slot_duration);
Some(Delay::new(wait_until))
}
Some(d) => Some(d),
diff --git a/substrate/core/network/src/test/mod.rs b/substrate/core/network/src/test/mod.rs
index 9931826ae2f..58d8a91c2e5 100644
--- a/substrate/core/network/src/test/mod.rs
+++ b/substrate/core/network/src/test/mod.rs
@@ -517,7 +517,7 @@ impl<D, S: NetworkSpecialization<Block>> Peer<D, S> {
use_tokio: bool,
network_to_protocol_sender: mpsc::UnboundedSender<FromNetworkMsg<Block>>,
protocol_sender: mpsc::UnboundedSender<ProtocolMsg<Block, S>>,
- network_sender: mpsc::UnboundedSender<NetworkMsg<Block>>,
+ _network_sender: mpsc::UnboundedSender<NetworkMsg<Block>>,
network_port: mpsc::UnboundedReceiver<NetworkMsg<Block>>,
data: D,
) -> Self {
diff --git a/substrate/core/test-runtime/src/lib.rs b/substrate/core/test-runtime/src/lib.rs
index 7a68439a07b..0916cad93d0 100644
--- a/substrate/core/test-runtime/src/lib.rs
+++ b/substrate/core/test-runtime/src/lib.rs
@@ -470,6 +470,7 @@ cfg_if! {
slot_duration: 1,
expected_block_time: 1,
threshold: std::u64::MAX,
+ median_required_blocks: 100,
}
}
fn authorities() -> Vec<BabeId> { system::authorities() }
@@ -611,6 +612,7 @@ cfg_if! {
impl consensus_babe::BabeApi<Block> for Runtime {
fn startup_data() -> consensus_babe::BabeConfiguration {
consensus_babe::BabeConfiguration {
+ median_required_blocks: 0,
slot_duration: 1,
expected_block_time: 1,
threshold: core::u64::MAX,
--
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