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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
@@ -806,7 +806,6 @@ struct DirectedChannelLiquidity<L: Deref<Target = u64>, BRT: Deref<Target = Hist
806806
capacity_msat: u64,
807807
last_updated: T,
808808
offset_history_last_updated: T,
809-
decay_params: ProbabilisticScoringDecayParameters,
810809
}
811810

812811
impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> where L::Target: Logger {
@@ -838,7 +837,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
838837
let log_direction = |source, target| {
839838
if let Some((directed_info, _)) = chan_debug.as_directed_to(target) {
840839
let amt = directed_info.effective_capacity().as_msat();
841-
let dir_liq = liq.as_directed(source, target, amt, self.decay_params);
840+
let dir_liq = liq.as_directed(source, target, amt);
842841

843842
let min_buckets = &dir_liq.liquidity_history.min_liquidity_offset_history.buckets;
844843
let max_buckets = &dir_liq.liquidity_history.max_liquidity_offset_history.buckets;
@@ -890,7 +889,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
890889
if let Some(liq) = self.channel_liquidities.get(&scid) {
891890
if let Some((directed_info, source)) = chan.as_directed_to(target) {
892891
let amt = directed_info.effective_capacity().as_msat();
893-
let dir_liq = liq.as_directed(source, target, amt, self.decay_params);
892+
let dir_liq = liq.as_directed(source, target, amt);
894893
return Some((dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat()));
895894
}
896895
}
@@ -932,7 +931,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
932931
if let Some(liq) = self.channel_liquidities.get(&scid) {
933932
if let Some((directed_info, source)) = chan.as_directed_to(target) {
934933
let amt = directed_info.effective_capacity().as_msat();
935-
let dir_liq = liq.as_directed(source, target, amt, self.decay_params);
934+
let dir_liq = liq.as_directed(source, target, amt);
936935

937936
let min_buckets = dir_liq.liquidity_history.min_liquidity_offset_history.buckets;
938937
let mut max_buckets = dir_liq.liquidity_history.max_liquidity_offset_history.buckets;
@@ -963,7 +962,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ProbabilisticScorer<G, L> whe
963962
if let Some(liq) = self.channel_liquidities.get(&scid) {
964963
if let Some((directed_info, source)) = chan.as_directed_to(target) {
965964
let capacity_msat = directed_info.effective_capacity().as_msat();
966-
let dir_liq = liq.as_directed(source, target, capacity_msat, self.decay_params);
965+
let dir_liq = liq.as_directed(source, target, capacity_msat);
967966

968967
return dir_liq.liquidity_history.calculate_success_probability_times_billion(
969968
&params, amount_msat, capacity_msat
@@ -990,7 +989,7 @@ impl ChannelLiquidity {
990989
/// Returns a view of the channel liquidity directed from `source` to `target` assuming
991990
/// `capacity_msat`.
992991
fn as_directed(
993-
&self, source: &NodeId, target: &NodeId, capacity_msat: u64, decay_params: ProbabilisticScoringDecayParameters
992+
&self, source: &NodeId, target: &NodeId, capacity_msat: u64,
994993
) -> DirectedChannelLiquidity<&u64, &HistoricalBucketRangeTracker, &Duration> {
995994
let (min_liquidity_offset_msat, max_liquidity_offset_msat, min_liquidity_offset_history, max_liquidity_offset_history) =
996995
if source < target {
@@ -1011,14 +1010,13 @@ impl ChannelLiquidity {
10111010
capacity_msat,
10121011
last_updated: &self.last_updated,
10131012
offset_history_last_updated: &self.offset_history_last_updated,
1014-
decay_params: decay_params,
10151013
}
10161014
}
10171015

10181016
/// Returns a mutable view of the channel liquidity directed from `source` to `target` assuming
10191017
/// `capacity_msat`.
10201018
fn as_directed_mut(
1021-
&mut self, source: &NodeId, target: &NodeId, capacity_msat: u64, decay_params: ProbabilisticScoringDecayParameters
1019+
&mut self, source: &NodeId, target: &NodeId, capacity_msat: u64,
10221020
) -> DirectedChannelLiquidity<&mut u64, &mut HistoricalBucketRangeTracker, &mut Duration> {
10231021
let (min_liquidity_offset_msat, max_liquidity_offset_msat, min_liquidity_offset_history, max_liquidity_offset_history) =
10241022
if source < target {
@@ -1039,7 +1037,6 @@ impl ChannelLiquidity {
10391037
capacity_msat,
10401038
last_updated: &mut self.last_updated,
10411039
offset_history_last_updated: &mut self.offset_history_last_updated,
1042-
decay_params: decay_params,
10431040
}
10441041
}
10451042

@@ -1289,14 +1286,6 @@ DirectedChannelLiquidity<L, BRT, T> {
12891286
/// state"), we allow the caller to set an offset applied to our liquidity bounds which
12901287
/// represents the amount of the successful payment we just made.
12911288
fn update_history_buckets(&mut self, bucket_offset_msat: u64, duration_since_epoch: Duration) {
1292-
let half_lives =
1293-
duration_since_epoch.checked_sub(*self.offset_history_last_updated)
1294-
.unwrap_or(Duration::ZERO).as_secs()
1295-
.checked_div(self.decay_params.historical_no_updates_half_life.as_secs())
1296-
.map(|v| v.try_into().unwrap_or(u32::max_value())).unwrap_or(u32::max_value());
1297-
self.liquidity_history.min_liquidity_offset_history.time_decay_data(half_lives);
1298-
self.liquidity_history.max_liquidity_offset_history.time_decay_data(half_lives);
1299-
13001289
self.liquidity_history.min_liquidity_offset_history.track_datapoint(
13011290
*self.min_liquidity_offset_msat + bucket_offset_msat, self.capacity_msat
13021291
);
@@ -1369,7 +1358,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ScoreLookUp for Probabilistic
13691358
self.channel_liquidities
13701359
.get(&scid)
13711360
.unwrap_or(&ChannelLiquidity::new(Duration::ZERO))
1372-
.as_directed(&source, &target, capacity_msat, self.decay_params)
1361+
.as_directed(&source, &target, capacity_msat)
13731362
.penalty_msat(amount_msat, score_params)
13741363
.saturating_add(anti_probing_penalty_msat)
13751364
.saturating_add(base_penalty_msat)
@@ -1399,14 +1388,14 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ScoreUpdate for Probabilistic
13991388
self.channel_liquidities
14001389
.entry(hop.short_channel_id)
14011390
.or_insert_with(|| ChannelLiquidity::new(duration_since_epoch))
1402-
.as_directed_mut(source, &target, capacity_msat, self.decay_params)
1391+
.as_directed_mut(source, &target, capacity_msat)
14031392
.failed_at_channel(amount_msat, duration_since_epoch,
14041393
format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
14051394
} else {
14061395
self.channel_liquidities
14071396
.entry(hop.short_channel_id)
14081397
.or_insert_with(|| ChannelLiquidity::new(duration_since_epoch))
1409-
.as_directed_mut(source, &target, capacity_msat, self.decay_params)
1398+
.as_directed_mut(source, &target, capacity_msat)
14101399
.failed_downstream(amount_msat, duration_since_epoch,
14111400
format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
14121401
}
@@ -1435,7 +1424,7 @@ impl<G: Deref<Target = NetworkGraph<L>>, L: Deref> ScoreUpdate for Probabilistic
14351424
self.channel_liquidities
14361425
.entry(hop.short_channel_id)
14371426
.or_insert_with(|| ChannelLiquidity::new(duration_since_epoch))
1438-
.as_directed_mut(source, &target, capacity_msat, self.decay_params)
1427+
.as_directed_mut(source, &target, capacity_msat)
14391428
.successful(amount_msat, duration_since_epoch,
14401429
format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
14411430
} else {
@@ -1959,14 +1948,6 @@ mod bucketed_history {
19591948
self.buckets[bucket] = self.buckets[bucket].saturating_add(BUCKET_FIXED_POINT_ONE);
19601949
}
19611950
}
1962-
/// Decay all buckets by the given number of half-lives. Used to more aggressively remove old
1963-
/// datapoints as we receive newer information.
1964-
#[inline]
1965-
pub(super) fn time_decay_data(&mut self, half_lives: u32) {
1966-
for e in self.buckets.iter_mut() {
1967-
*e = e.checked_shr(half_lives).unwrap_or(0);
1968-
}
1969-
}
19701951
}
19711952

19721953
impl_writeable_tlv_based!(HistoricalBucketRangeTracker, { (0, buckets, required) });
@@ -2359,52 +2340,52 @@ mod tests {
23592340
// Update minimum liquidity.
23602341

23612342
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2362-
.as_directed(&source, &target, 1_000, decay_params);
2343+
.as_directed(&source, &target, 1_000);
23632344
assert_eq!(liquidity.min_liquidity_msat(), 100);
23642345
assert_eq!(liquidity.max_liquidity_msat(), 300);
23652346

23662347
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2367-
.as_directed(&target, &source, 1_000, decay_params);
2348+
.as_directed(&target, &source, 1_000);
23682349
assert_eq!(liquidity.min_liquidity_msat(), 700);
23692350
assert_eq!(liquidity.max_liquidity_msat(), 900);
23702351

23712352
scorer.channel_liquidities.get_mut(&42).unwrap()
2372-
.as_directed_mut(&source, &target, 1_000, decay_params)
2353+
.as_directed_mut(&source, &target, 1_000)
23732354
.set_min_liquidity_msat(200, Duration::ZERO);
23742355

23752356
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2376-
.as_directed(&source, &target, 1_000, decay_params);
2357+
.as_directed(&source, &target, 1_000);
23772358
assert_eq!(liquidity.min_liquidity_msat(), 200);
23782359
assert_eq!(liquidity.max_liquidity_msat(), 300);
23792360

23802361
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2381-
.as_directed(&target, &source, 1_000, decay_params);
2362+
.as_directed(&target, &source, 1_000);
23822363
assert_eq!(liquidity.min_liquidity_msat(), 700);
23832364
assert_eq!(liquidity.max_liquidity_msat(), 800);
23842365

23852366
// Update maximum liquidity.
23862367

23872368
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2388-
.as_directed(&target, &recipient, 1_000, decay_params);
2369+
.as_directed(&target, &recipient, 1_000);
23892370
assert_eq!(liquidity.min_liquidity_msat(), 700);
23902371
assert_eq!(liquidity.max_liquidity_msat(), 900);
23912372

23922373
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2393-
.as_directed(&recipient, &target, 1_000, decay_params);
2374+
.as_directed(&recipient, &target, 1_000);
23942375
assert_eq!(liquidity.min_liquidity_msat(), 100);
23952376
assert_eq!(liquidity.max_liquidity_msat(), 300);
23962377

23972378
scorer.channel_liquidities.get_mut(&43).unwrap()
2398-
.as_directed_mut(&target, &recipient, 1_000, decay_params)
2379+
.as_directed_mut(&target, &recipient, 1_000)
23992380
.set_max_liquidity_msat(200, Duration::ZERO);
24002381

24012382
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2402-
.as_directed(&target, &recipient, 1_000, decay_params);
2383+
.as_directed(&target, &recipient, 1_000);
24032384
assert_eq!(liquidity.min_liquidity_msat(), 0);
24042385
assert_eq!(liquidity.max_liquidity_msat(), 200);
24052386

24062387
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2407-
.as_directed(&recipient, &target, 1_000, decay_params);
2388+
.as_directed(&recipient, &target, 1_000);
24082389
assert_eq!(liquidity.min_liquidity_msat(), 800);
24092390
assert_eq!(liquidity.max_liquidity_msat(), 1000);
24102391
}
@@ -2430,42 +2411,42 @@ mod tests {
24302411

24312412
// Check initial bounds.
24322413
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2433-
.as_directed(&source, &target, 1_000, decay_params);
2414+
.as_directed(&source, &target, 1_000);
24342415
assert_eq!(liquidity.min_liquidity_msat(), 400);
24352416
assert_eq!(liquidity.max_liquidity_msat(), 800);
24362417

24372418
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2438-
.as_directed(&target, &source, 1_000, decay_params);
2419+
.as_directed(&target, &source, 1_000);
24392420
assert_eq!(liquidity.min_liquidity_msat(), 200);
24402421
assert_eq!(liquidity.max_liquidity_msat(), 600);
24412422

24422423
// Reset from source to target.
24432424
scorer.channel_liquidities.get_mut(&42).unwrap()
2444-
.as_directed_mut(&source, &target, 1_000, decay_params)
2425+
.as_directed_mut(&source, &target, 1_000)
24452426
.set_min_liquidity_msat(900, Duration::ZERO);
24462427

24472428
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2448-
.as_directed(&source, &target, 1_000, decay_params);
2429+
.as_directed(&source, &target, 1_000);
24492430
assert_eq!(liquidity.min_liquidity_msat(), 900);
24502431
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
24512432

24522433
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2453-
.as_directed(&target, &source, 1_000, decay_params);
2434+
.as_directed(&target, &source, 1_000);
24542435
assert_eq!(liquidity.min_liquidity_msat(), 0);
24552436
assert_eq!(liquidity.max_liquidity_msat(), 100);
24562437

24572438
// Reset from target to source.
24582439
scorer.channel_liquidities.get_mut(&42).unwrap()
2459-
.as_directed_mut(&target, &source, 1_000, decay_params)
2440+
.as_directed_mut(&target, &source, 1_000)
24602441
.set_min_liquidity_msat(400, Duration::ZERO);
24612442

24622443
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2463-
.as_directed(&source, &target, 1_000, decay_params);
2444+
.as_directed(&source, &target, 1_000);
24642445
assert_eq!(liquidity.min_liquidity_msat(), 0);
24652446
assert_eq!(liquidity.max_liquidity_msat(), 600);
24662447

24672448
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2468-
.as_directed(&target, &source, 1_000, decay_params);
2449+
.as_directed(&target, &source, 1_000);
24692450
assert_eq!(liquidity.min_liquidity_msat(), 400);
24702451
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
24712452
}
@@ -2491,42 +2472,42 @@ mod tests {
24912472

24922473
// Check initial bounds.
24932474
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2494-
.as_directed(&source, &target, 1_000, decay_params);
2475+
.as_directed(&source, &target, 1_000);
24952476
assert_eq!(liquidity.min_liquidity_msat(), 400);
24962477
assert_eq!(liquidity.max_liquidity_msat(), 800);
24972478

24982479
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2499-
.as_directed(&target, &source, 1_000, decay_params);
2480+
.as_directed(&target, &source, 1_000);
25002481
assert_eq!(liquidity.min_liquidity_msat(), 200);
25012482
assert_eq!(liquidity.max_liquidity_msat(), 600);
25022483

25032484
// Reset from source to target.
25042485
scorer.channel_liquidities.get_mut(&42).unwrap()
2505-
.as_directed_mut(&source, &target, 1_000, decay_params)
2486+
.as_directed_mut(&source, &target, 1_000)
25062487
.set_max_liquidity_msat(300, Duration::ZERO);
25072488

25082489
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2509-
.as_directed(&source, &target, 1_000, decay_params);
2490+
.as_directed(&source, &target, 1_000);
25102491
assert_eq!(liquidity.min_liquidity_msat(), 0);
25112492
assert_eq!(liquidity.max_liquidity_msat(), 300);
25122493

25132494
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2514-
.as_directed(&target, &source, 1_000, decay_params);
2495+
.as_directed(&target, &source, 1_000);
25152496
assert_eq!(liquidity.min_liquidity_msat(), 700);
25162497
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
25172498

25182499
// Reset from target to source.
25192500
scorer.channel_liquidities.get_mut(&42).unwrap()
2520-
.as_directed_mut(&target, &source, 1_000, decay_params)
2501+
.as_directed_mut(&target, &source, 1_000)
25212502
.set_max_liquidity_msat(600, Duration::ZERO);
25222503

25232504
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2524-
.as_directed(&source, &target, 1_000, decay_params);
2505+
.as_directed(&source, &target, 1_000);
25252506
assert_eq!(liquidity.min_liquidity_msat(), 400);
25262507
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
25272508

25282509
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2529-
.as_directed(&target, &source, 1_000, decay_params);
2510+
.as_directed(&target, &source, 1_000);
25302511
assert_eq!(liquidity.min_liquidity_msat(), 0);
25312512
assert_eq!(liquidity.max_liquidity_msat(), 600);
25322513
}
@@ -3660,7 +3641,7 @@ mod tests {
36603641
scorer.payment_path_failed(&path, 43, Duration::ZERO);
36613642

36623643
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
3663-
.as_directed(&source, &target, 1_000, decay_params);
3644+
.as_directed(&source, &target, 1_000);
36643645
assert_eq!(liquidity.min_liquidity_msat(), 256);
36653646
assert_eq!(liquidity.max_liquidity_msat(), 768);
36663647
}

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