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TheBlueMattTheBlueMatt
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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 {
@@ -1951,14 +1940,6 @@ mod bucketed_history {
19511940
self.buckets[bucket] = self.buckets[bucket].saturating_add(BUCKET_FIXED_POINT_ONE);
19521941
}
19531942
}
1954-
/// Decay all buckets by the given number of half-lives. Used to more aggressively remove old
1955-
/// datapoints as we receive newer information.
1956-
#[inline]
1957-
pub(super) fn time_decay_data(&mut self, half_lives: u32) {
1958-
for e in self.buckets.iter_mut() {
1959-
*e = e.checked_shr(half_lives).unwrap_or(0);
1960-
}
1961-
}
19621943
}
19631944

19641945
impl_writeable_tlv_based!(HistoricalBucketRangeTracker, { (0, buckets, required) });
@@ -2354,52 +2335,52 @@ mod tests {
23542335
// Update minimum liquidity.
23552336

23562337
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2357-
.as_directed(&source, &target, 1_000, decay_params);
2338+
.as_directed(&source, &target, 1_000);
23582339
assert_eq!(liquidity.min_liquidity_msat(), 100);
23592340
assert_eq!(liquidity.max_liquidity_msat(), 300);
23602341

23612342
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2362-
.as_directed(&target, &source, 1_000, decay_params);
2343+
.as_directed(&target, &source, 1_000);
23632344
assert_eq!(liquidity.min_liquidity_msat(), 700);
23642345
assert_eq!(liquidity.max_liquidity_msat(), 900);
23652346

23662347
scorer.channel_liquidities.get_mut(&42).unwrap()
2367-
.as_directed_mut(&source, &target, 1_000, decay_params)
2348+
.as_directed_mut(&source, &target, 1_000)
23682349
.set_min_liquidity_msat(200, Duration::ZERO);
23692350

23702351
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2371-
.as_directed(&source, &target, 1_000, decay_params);
2352+
.as_directed(&source, &target, 1_000);
23722353
assert_eq!(liquidity.min_liquidity_msat(), 200);
23732354
assert_eq!(liquidity.max_liquidity_msat(), 300);
23742355

23752356
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2376-
.as_directed(&target, &source, 1_000, decay_params);
2357+
.as_directed(&target, &source, 1_000);
23772358
assert_eq!(liquidity.min_liquidity_msat(), 700);
23782359
assert_eq!(liquidity.max_liquidity_msat(), 800);
23792360

23802361
// Update maximum liquidity.
23812362

23822363
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2383-
.as_directed(&target, &recipient, 1_000, decay_params);
2364+
.as_directed(&target, &recipient, 1_000);
23842365
assert_eq!(liquidity.min_liquidity_msat(), 700);
23852366
assert_eq!(liquidity.max_liquidity_msat(), 900);
23862367

23872368
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2388-
.as_directed(&recipient, &target, 1_000, decay_params);
2369+
.as_directed(&recipient, &target, 1_000);
23892370
assert_eq!(liquidity.min_liquidity_msat(), 100);
23902371
assert_eq!(liquidity.max_liquidity_msat(), 300);
23912372

23922373
scorer.channel_liquidities.get_mut(&43).unwrap()
2393-
.as_directed_mut(&target, &recipient, 1_000, decay_params)
2374+
.as_directed_mut(&target, &recipient, 1_000)
23942375
.set_max_liquidity_msat(200, Duration::ZERO);
23952376

23962377
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2397-
.as_directed(&target, &recipient, 1_000, decay_params);
2378+
.as_directed(&target, &recipient, 1_000);
23982379
assert_eq!(liquidity.min_liquidity_msat(), 0);
23992380
assert_eq!(liquidity.max_liquidity_msat(), 200);
24002381

24012382
let liquidity = scorer.channel_liquidities.get(&43).unwrap()
2402-
.as_directed(&recipient, &target, 1_000, decay_params);
2383+
.as_directed(&recipient, &target, 1_000);
24032384
assert_eq!(liquidity.min_liquidity_msat(), 800);
24042385
assert_eq!(liquidity.max_liquidity_msat(), 1000);
24052386
}
@@ -2425,42 +2406,42 @@ mod tests {
24252406

24262407
// Check initial bounds.
24272408
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2428-
.as_directed(&source, &target, 1_000, decay_params);
2409+
.as_directed(&source, &target, 1_000);
24292410
assert_eq!(liquidity.min_liquidity_msat(), 400);
24302411
assert_eq!(liquidity.max_liquidity_msat(), 800);
24312412

24322413
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2433-
.as_directed(&target, &source, 1_000, decay_params);
2414+
.as_directed(&target, &source, 1_000);
24342415
assert_eq!(liquidity.min_liquidity_msat(), 200);
24352416
assert_eq!(liquidity.max_liquidity_msat(), 600);
24362417

24372418
// Reset from source to target.
24382419
scorer.channel_liquidities.get_mut(&42).unwrap()
2439-
.as_directed_mut(&source, &target, 1_000, decay_params)
2420+
.as_directed_mut(&source, &target, 1_000)
24402421
.set_min_liquidity_msat(900, Duration::ZERO);
24412422

24422423
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2443-
.as_directed(&source, &target, 1_000, decay_params);
2424+
.as_directed(&source, &target, 1_000);
24442425
assert_eq!(liquidity.min_liquidity_msat(), 900);
24452426
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
24462427

24472428
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2448-
.as_directed(&target, &source, 1_000, decay_params);
2429+
.as_directed(&target, &source, 1_000);
24492430
assert_eq!(liquidity.min_liquidity_msat(), 0);
24502431
assert_eq!(liquidity.max_liquidity_msat(), 100);
24512432

24522433
// Reset from target to source.
24532434
scorer.channel_liquidities.get_mut(&42).unwrap()
2454-
.as_directed_mut(&target, &source, 1_000, decay_params)
2435+
.as_directed_mut(&target, &source, 1_000)
24552436
.set_min_liquidity_msat(400, Duration::ZERO);
24562437

24572438
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2458-
.as_directed(&source, &target, 1_000, decay_params);
2439+
.as_directed(&source, &target, 1_000);
24592440
assert_eq!(liquidity.min_liquidity_msat(), 0);
24602441
assert_eq!(liquidity.max_liquidity_msat(), 600);
24612442

24622443
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2463-
.as_directed(&target, &source, 1_000, decay_params);
2444+
.as_directed(&target, &source, 1_000);
24642445
assert_eq!(liquidity.min_liquidity_msat(), 400);
24652446
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
24662447
}
@@ -2486,42 +2467,42 @@ mod tests {
24862467

24872468
// Check initial bounds.
24882469
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2489-
.as_directed(&source, &target, 1_000, decay_params);
2470+
.as_directed(&source, &target, 1_000);
24902471
assert_eq!(liquidity.min_liquidity_msat(), 400);
24912472
assert_eq!(liquidity.max_liquidity_msat(), 800);
24922473

24932474
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2494-
.as_directed(&target, &source, 1_000, decay_params);
2475+
.as_directed(&target, &source, 1_000);
24952476
assert_eq!(liquidity.min_liquidity_msat(), 200);
24962477
assert_eq!(liquidity.max_liquidity_msat(), 600);
24972478

24982479
// Reset from source to target.
24992480
scorer.channel_liquidities.get_mut(&42).unwrap()
2500-
.as_directed_mut(&source, &target, 1_000, decay_params)
2481+
.as_directed_mut(&source, &target, 1_000)
25012482
.set_max_liquidity_msat(300, Duration::ZERO);
25022483

25032484
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2504-
.as_directed(&source, &target, 1_000, decay_params);
2485+
.as_directed(&source, &target, 1_000);
25052486
assert_eq!(liquidity.min_liquidity_msat(), 0);
25062487
assert_eq!(liquidity.max_liquidity_msat(), 300);
25072488

25082489
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2509-
.as_directed(&target, &source, 1_000, decay_params);
2490+
.as_directed(&target, &source, 1_000);
25102491
assert_eq!(liquidity.min_liquidity_msat(), 700);
25112492
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
25122493

25132494
// Reset from target to source.
25142495
scorer.channel_liquidities.get_mut(&42).unwrap()
2515-
.as_directed_mut(&target, &source, 1_000, decay_params)
2496+
.as_directed_mut(&target, &source, 1_000)
25162497
.set_max_liquidity_msat(600, Duration::ZERO);
25172498

25182499
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2519-
.as_directed(&source, &target, 1_000, decay_params);
2500+
.as_directed(&source, &target, 1_000);
25202501
assert_eq!(liquidity.min_liquidity_msat(), 400);
25212502
assert_eq!(liquidity.max_liquidity_msat(), 1_000);
25222503

25232504
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2524-
.as_directed(&target, &source, 1_000, decay_params);
2505+
.as_directed(&target, &source, 1_000);
25252506
assert_eq!(liquidity.min_liquidity_msat(), 0);
25262507
assert_eq!(liquidity.max_liquidity_msat(), 600);
25272508
}
@@ -3464,7 +3445,7 @@ mod tests {
34643445
scorer.payment_path_failed(&path, 43, Duration::ZERO);
34653446

34663447
let liquidity = scorer.channel_liquidities.get(&42).unwrap()
3467-
.as_directed(&source, &target, 1_000, decay_params);
3448+
.as_directed(&source, &target, 1_000);
34683449
assert_eq!(liquidity.min_liquidity_msat(), 256);
34693450
assert_eq!(liquidity.max_liquidity_msat(), 768);
34703451
}

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