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Drop half-life-based bucket decay in update_history_buckets
Because we decay the bucket information in the background, there's not much reason to try to decay them immediately prior to updating, and in removing that we can also clean up a good bit of dead code, which we do here.
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‎lightning/src/routing/scoring.rs‎

Lines changed: 37 additions & 56 deletions
Original file line numberDiff line numberDiff line change
@@ -807,7 +807,6 @@ struct DirectedChannelLiquidity<L: Deref<Target = u64>, BRT: Deref<Target = Hist
807807
capacity_msat: u64,
808808
last_updated: T,
809809
offset_history_last_updated: T,
810-
decay_params: ProbabilisticScoringDecayParameters,
811810
}
812811

813812
impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> where L::Target: Logger {
@@ -839,7 +838,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
839838
let log_direction = |source, target| {
840839
if let Some((directed_info, _)) = chan_debug.as_directed_to(target) {
841840
let amt = directed_info.effective_capacity().as_msat();
842-
let dir_liq = liq.as_directed(source, target, amt, self.decay_params);
841+
let dir_liq = liq.as_directed(source, target, amt);
843842

844843
let min_buckets = &dir_liq.liquidity_history.min_liquidity_offset_history.buckets;
845844
let max_buckets = &dir_liq.liquidity_history.max_liquidity_offset_history.buckets;
@@ -891,7 +890,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
891890
if let Some(liq) = self.channel_liquidities.get(&scid) {
892891
if let Some((directed_info, source)) = chan.as_directed_to(target) {
893892
let amt = directed_info.effective_capacity().as_msat();
894-
let dir_liq = liq.as_directed(source, target, amt, self.decay_params);
893+
let dir_liq = liq.as_directed(source, target, amt);
895894
return Some((dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat()));
896895
}
897896
}
@@ -933,7 +932,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
933932
if let Some(liq) = self.channel_liquidities.get(&scid) {
934933
if let Some((directed_info, source)) = chan.as_directed_to(target) {
935934
let amt = directed_info.effective_capacity().as_msat();
936-
let dir_liq = liq.as_directed(source, target, amt, self.decay_params);
935+
let dir_liq = liq.as_directed(source, target, amt);
937936

938937
let min_buckets = dir_liq.liquidity_history.min_liquidity_offset_history.buckets;
939938
let mut max_buckets = dir_liq.liquidity_history.max_liquidity_offset_history.buckets;
@@ -964,7 +963,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
964963
if let Some(liq) = self.channel_liquidities.get(&scid) {
965964
if let Some((directed_info, source)) = chan.as_directed_to(target) {
966965
let capacity_msat = directed_info.effective_capacity().as_msat();
967-
let dir_liq = liq.as_directed(source, target, capacity_msat, self.decay_params);
966+
let dir_liq = liq.as_directed(source, target, capacity_msat);
968967

969968
return dir_liq.liquidity_history.calculate_success_probability_times_billion(
970969
&params, amount_msat, capacity_msat
@@ -991,7 +990,7 @@ impl ChannelLiquidity {
991990
/// Returns a view of the channel liquidity directed from `source` to `target` assuming
992991
/// `capacity_msat`.
993992
fn as_directed(
994-
&self, source: &NodeId, target: &NodeId, capacity_msat: u64, decay_params: ProbabilisticScoringDecayParameters
993+
&self, source: &NodeId, target: &NodeId, capacity_msat: u64,
995994
) -> DirectedChannelLiquidity<&u64, &HistoricalBucketRangeTracker, &Duration> {
996995
let (min_liquidity_offset_msat, max_liquidity_offset_msat, min_liquidity_offset_history, max_liquidity_offset_history) =
997996
if source < target {
@@ -1012,14 +1011,13 @@ impl ChannelLiquidity {
10121011
capacity_msat,
10131012
last_updated: &self.last_updated,
10141013
offset_history_last_updated: &self.offset_history_last_updated,
1015-
decay_params: decay_params,
10161014
}
10171015
}
10181016

10191017
/// Returns a mutable view of the channel liquidity directed from `source` to `target` assuming
10201018
/// `capacity_msat`.
10211019
fn as_directed_mut(
1022-
&mut self, source: &NodeId, target: &NodeId, capacity_msat: u64, decay_params: ProbabilisticScoringDecayParameters
1020+
&mut self, source: &NodeId, target: &NodeId, capacity_msat: u64,
10231021
) -> DirectedChannelLiquidity<&mut u64, &mut HistoricalBucketRangeTracker, &mut Duration> {
10241022
let (min_liquidity_offset_msat, max_liquidity_offset_msat, min_liquidity_offset_history, max_liquidity_offset_history) =
10251023
if source < target {
@@ -1040,7 +1038,6 @@ impl ChannelLiquidity {
10401038
capacity_msat,
10411039
last_updated: &mut self.last_updated,
10421040
offset_history_last_updated: &mut self.offset_history_last_updated,
1043-
decay_params: decay_params,
10441041
}
10451042
}
10461043

@@ -1290,14 +1287,6 @@ DirectedChannelLiquidity<L, BRT, T> {
12901287
/// state"), we allow the caller to set an offset applied to our liquidity bounds which
12911288
/// represents the amount of the successful payment we just made.
12921289
fn update_history_buckets(&mut self, bucket_offset_msat: u64, duration_since_epoch: Duration) {
1293-
let half_lives =
1294-
duration_since_epoch.checked_sub(*self.offset_history_last_updated)
1295-
.unwrap_or(Duration::ZERO).as_secs()
1296-
.checked_div(self.decay_params.historical_no_updates_half_life.as_secs())
1297-
.map(|v| v.try_into().unwrap_or(u32::max_value())).unwrap_or(u32::max_value());
1298-
self.liquidity_history.min_liquidity_offset_history.time_decay_data(half_lives);
1299-
self.liquidity_history.max_liquidity_offset_history.time_decay_data(half_lives);
1300-
13011290
self.liquidity_history.min_liquidity_offset_history.track_datapoint(
13021291
*self.min_liquidity_offset_msat + bucket_offset_msat, self.capacity_msat
13031292
);
@@ -1363,7 +1352,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ScoreLookUp for Probabilistic
13631352
self.channel_liquidities
13641353
.get(&short_channel_id)
13651354
.unwrap_or(&ChannelLiquidity::new(Duration::ZERO))
1366-
.as_directed(source, target, capacity_msat, self.decay_params)
1355+
.as_directed(source, target, capacity_msat)
13671356
.penalty_msat(amount_msat, score_params)
13681357
.saturating_add(anti_probing_penalty_msat)
13691358
.saturating_add(base_penalty_msat)
@@ -1393,14 +1382,14 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ScoreUpdate for Probabilistic
13931382
self.channel_liquidities
13941383
.entry(hop.short_channel_id)
13951384
.or_insert_with(|| ChannelLiquidity::new(duration_since_epoch))
1396-
.as_directed_mut(source, &target, capacity_msat, self.decay_params)
1385+
.as_directed_mut(source, &target, capacity_msat)
13971386
.failed_at_channel(amount_msat, duration_since_epoch,
13981387
format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
13991388
} else {
14001389
self.channel_liquidities
14011390
.entry(hop.short_channel_id)
14021391
.or_insert_with(|| ChannelLiquidity::new(duration_since_epoch))
1403-
.as_directed_mut(source, &target, capacity_msat, self.decay_params)
1392+
.as_directed_mut(source, &target, capacity_msat)
14041393
.failed_downstream(amount_msat, duration_since_epoch,
14051394
format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
14061395
}
@@ -1429,7 +1418,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ScoreUpdate for Probabilistic
14291418
self.channel_liquidities
14301419
.entry(hop.short_channel_id)
14311420
.or_insert_with(|| ChannelLiquidity::new(duration_since_epoch))
1432-
.as_directed_mut(source, &target, capacity_msat, self.decay_params)
1421+
.as_directed_mut(source, &target, capacity_msat)
14331422
.successful(amount_msat, duration_since_epoch,
14341423
format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
14351424
} else {
@@ -1953,14 +1942,6 @@ mod bucketed_history {
19531942
self.buckets[bucket] = self.buckets[bucket].saturating_add(BUCKET_FIXED_POINT_ONE);
19541943
}
19551944
}
1956-
/// Decay all buckets by the given number of half-lives. Used to more aggressively remove old
1957-
/// datapoints as we receive newer information.
1958-
#[inline]
1959-
pub(super) fn time_decay_data(&mut self, half_lives: u32) {
1960-
for e in self.buckets.iter_mut() {
1961-
*e = e.checked_shr(half_lives).unwrap_or(0);
1962-
}
1963-
}
19641945
}
19651946

19661947
impl_writeable_tlv_based!(HistoricalBucketRangeTracker, { (0, buckets, required) });
@@ -2357,52 +2338,52 @@ mod tests {
23572338
// Update minimum liquidity.
23582339

23592340
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2360-
.as_directed(&source, &target, 1_000, decay_params);
2341+
.as_directed(&source, &target, 1_000);
23612342
assert_eq!(liquidity.min_liquidity_msat(), 100);
23622343
assert_eq!(liquidity.max_liquidity_msat(), 300);
23632344

23642345
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2365-
.as_directed(&target, &source, 1_000, decay_params);
2346+
.as_directed(&target, &source, 1_000);
23662347
assert_eq!(liquidity.min_liquidity_msat(), 700);
23672348
assert_eq!(liquidity.max_liquidity_msat(), 900);
23682349

23692350
scorer.channel_liquidities.get_mut(&42).unwrap()
2370-
.as_directed_mut(&source, &target, 1_000, decay_params)
2351+
.as_directed_mut(&source, &target, 1_000)
23712352
.set_min_liquidity_msat(200, Duration::ZERO);
23722353

23732354
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2374-
.as_directed(&source, &target, 1_000, decay_params);
2355+
.as_directed(&source, &target, 1_000);
23752356
assert_eq!(liquidity.min_liquidity_msat(), 200);
23762357
assert_eq!(liquidity.max_liquidity_msat(), 300);
23772358

23782359
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2379-
.as_directed(&target, &source, 1_000, decay_params);
2360+
.as_directed(&target, &source, 1_000);
23802361
assert_eq!(liquidity.min_liquidity_msat(), 700);
23812362
assert_eq!(liquidity.max_liquidity_msat(), 800);
23822363

23832364
// Update maximum liquidity.
23842365

23852366
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2386-
.as_directed(&target, &recipient, 1_000, decay_params);
2367+
.as_directed(&target, &recipient, 1_000);
23872368
assert_eq!(liquidity.min_liquidity_msat(), 700);
23882369
assert_eq!(liquidity.max_liquidity_msat(), 900);
23892370

23902371
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2391-
.as_directed(&recipient, &target, 1_000, decay_params);
2372+
.as_directed(&recipient, &target, 1_000);
23922373
assert_eq!(liquidity.min_liquidity_msat(), 100);
23932374
assert_eq!(liquidity.max_liquidity_msat(), 300);
23942375

23952376
scorer.channel_liquidities.get_mut(&43).unwrap()
2396-
.as_directed_mut(&target, &recipient, 1_000, decay_params)
2377+
.as_directed_mut(&target, &recipient, 1_000)
23972378
.set_max_liquidity_msat(200, Duration::ZERO);
23982379

23992380
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2400-
.as_directed(&target, &recipient, 1_000, decay_params);
2381+
.as_directed(&target, &recipient, 1_000);
24012382
assert_eq!(liquidity.min_liquidity_msat(), 0);
24022383
assert_eq!(liquidity.max_liquidity_msat(), 200);
24032384

24042385
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2405-
.as_directed(&recipient, &target, 1_000, decay_params);
2386+
.as_directed(&recipient, &target, 1_000);
24062387
assert_eq!(liquidity.min_liquidity_msat(), 800);
24072388
assert_eq!(liquidity.max_liquidity_msat(), 1000);
24082389
}
@@ -2428,42 +2409,42 @@ mod tests {
24282409

24292410
// Check initial bounds.
24302411
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2431-
.as_directed(&source, &target, 1_000, decay_params);
2412+
.as_directed(&source, &target, 1_000);
24322413
assert_eq!(liquidity.min_liquidity_msat(), 400);
24332414
assert_eq!(liquidity.max_liquidity_msat(), 800);
24342415

24352416
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2436-
.as_directed(&target, &source, 1_000, decay_params);
2417+
.as_directed(&target, &source, 1_000);
24372418
assert_eq!(liquidity.min_liquidity_msat(), 200);
24382419
assert_eq!(liquidity.max_liquidity_msat(), 600);
24392420

24402421
// Reset from source to target.
24412422
scorer.channel_liquidities.get_mut(&42).unwrap()
2442-
.as_directed_mut(&source, &target, 1_000, decay_params)
2423+
.as_directed_mut(&source, &target, 1_000)
24432424
.set_min_liquidity_msat(900, Duration::ZERO);
24442425

24452426
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2446-
.as_directed(&source, &target, 1_000, decay_params);
2427+
.as_directed(&source, &target, 1_000);
24472428
assert_eq!(liquidity.min_liquidity_msat(), 900);
24482429
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
24492430

24502431
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2451-
.as_directed(&target, &source, 1_000, decay_params);
2432+
.as_directed(&target, &source, 1_000);
24522433
assert_eq!(liquidity.min_liquidity_msat(), 0);
24532434
assert_eq!(liquidity.max_liquidity_msat(), 100);
24542435

24552436
// Reset from target to source.
24562437
scorer.channel_liquidities.get_mut(&42).unwrap()
2457-
.as_directed_mut(&target, &source, 1_000, decay_params)
2438+
.as_directed_mut(&target, &source, 1_000)
24582439
.set_min_liquidity_msat(400, Duration::ZERO);
24592440

24602441
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2461-
.as_directed(&source, &target, 1_000, decay_params);
2442+
.as_directed(&source, &target, 1_000);
24622443
assert_eq!(liquidity.min_liquidity_msat(), 0);
24632444
assert_eq!(liquidity.max_liquidity_msat(), 600);
24642445

24652446
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2466-
.as_directed(&target, &source, 1_000, decay_params);
2447+
.as_directed(&target, &source, 1_000);
24672448
assert_eq!(liquidity.min_liquidity_msat(), 400);
24682449
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
24692450
}
@@ -2489,42 +2470,42 @@ mod tests {
24892470

24902471
// Check initial bounds.
24912472
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2492-
.as_directed(&source, &target, 1_000, decay_params);
2473+
.as_directed(&source, &target, 1_000);
24932474
assert_eq!(liquidity.min_liquidity_msat(), 400);
24942475
assert_eq!(liquidity.max_liquidity_msat(), 800);
24952476

24962477
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2497-
.as_directed(&target, &source, 1_000, decay_params);
2478+
.as_directed(&target, &source, 1_000);
24982479
assert_eq!(liquidity.min_liquidity_msat(), 200);
24992480
assert_eq!(liquidity.max_liquidity_msat(), 600);
25002481

25012482
// Reset from source to target.
25022483
scorer.channel_liquidities.get_mut(&42).unwrap()
2503-
.as_directed_mut(&source, &target, 1_000, decay_params)
2484+
.as_directed_mut(&source, &target, 1_000)
25042485
.set_max_liquidity_msat(300, Duration::ZERO);
25052486

25062487
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2507-
.as_directed(&source, &target, 1_000, decay_params);
2488+
.as_directed(&source, &target, 1_000);
25082489
assert_eq!(liquidity.min_liquidity_msat(), 0);
25092490
assert_eq!(liquidity.max_liquidity_msat(), 300);
25102491

25112492
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2512-
.as_directed(&target, &source, 1_000, decay_params);
2493+
.as_directed(&target, &source, 1_000);
25132494
assert_eq!(liquidity.min_liquidity_msat(), 700);
25142495
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
25152496

25162497
// Reset from target to source.
25172498
scorer.channel_liquidities.get_mut(&42).unwrap()
2518-
.as_directed_mut(&target, &source, 1_000, decay_params)
2499+
.as_directed_mut(&target, &source, 1_000)
25192500
.set_max_liquidity_msat(600, Duration::ZERO);
25202501

25212502
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2522-
.as_directed(&source, &target, 1_000, decay_params);
2503+
.as_directed(&source, &target, 1_000);
25232504
assert_eq!(liquidity.min_liquidity_msat(), 400);
25242505
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
25252506

25262507
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2527-
.as_directed(&target, &source, 1_000, decay_params);
2508+
.as_directed(&target, &source, 1_000);
25282509
assert_eq!(liquidity.min_liquidity_msat(), 0);
25292510
assert_eq!(liquidity.max_liquidity_msat(), 600);
25302511
}
@@ -3467,7 +3448,7 @@ mod tests {
34673448
scorer.payment_path_failed(&path, 43, Duration::ZERO);
34683449

34693450
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
3470-
.as_directed(&source, &target, 1_000, decay_params);
3451+
.as_directed(&source, &target, 1_000);
34713452
assert_eq!(liquidity.min_liquidity_msat(), 256);
34723453
assert_eq!(liquidity.max_liquidity_msat(), 768);
34733454
}

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