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Merge pull request #26976 from EVAST9919/ur-alloc

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Fix huge allocation overhead in `UnstableRateCounter`
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Bartłomiej Dach 2024-02-05 19:45:34 +01:00 committed by GitHub
commit 4a6d392535
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GPG Key ID: B5690EEEBB952194
3 changed files with 57 additions and 13 deletions
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31
osu.Game.Benchmarks/BenchmarkUnstableRate.cs Normal file
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@ -0,0 +1,31 @@
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
using System.Collections.Generic;
using BenchmarkDotNet.Attributes;
using osu.Framework.Utils;
using osu.Game.Rulesets.Objects;
using osu.Game.Rulesets.Scoring;
namespace osu.Game.Benchmarks
{
public class BenchmarkUnstableRate : BenchmarkTest
{
private List<HitEvent> events = null!;
public override void SetUp()
{
base.SetUp();
events = new List<HitEvent>();
for (int i = 0; i < 1000; i++)
events.Add(new HitEvent(RNG.NextDouble(-200.0, 200.0), RNG.NextDouble(1.0, 2.0), HitResult.Great, new HitObject(), null, null));
}
[Benchmark]
public void CalculateUnstableRate()
{
_ = events.CalculateUnstableRate();
}
}
}

38
osu.Game/Rulesets/Scoring/HitEventExtensions.cs
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@ -13,6 +13,9 @@ namespace osu.Game.Rulesets.Scoring
/// <summary>
/// Calculates the "unstable rate" for a sequence of <see cref="HitEvent"/>s.
/// </summary>
/// <remarks>
/// Uses <a href="https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Welford's_online_algorithm">Welford's online algorithm</a>.
/// </remarks>
/// <returns>
/// A non-null <see langword="double"/> value if unstable rate could be calculated,
/// and <see langword="null"/> if unstable rate cannot be calculated due to <paramref name="hitEvents"/> being empty.
@ -21,9 +24,28 @@ namespace osu.Game.Rulesets.Scoring
{
Debug.Assert(hitEvents.All(ev => ev.GameplayRate != null));
// Division by gameplay rate is to account for TimeOffset scaling with gameplay rate.
double[] timeOffsets = hitEvents.Where(affectsUnstableRate).Select(ev => ev.TimeOffset / ev.GameplayRate!.Value).ToArray();
return 10 * standardDeviation(timeOffsets);
int count = 0;
double mean = 0;
double sumOfSquares = 0;
foreach (var e in hitEvents)
{
if (!affectsUnstableRate(e))
continue;
count++;
// Division by gameplay rate is to account for TimeOffset scaling with gameplay rate.
double currentValue = e.TimeOffset / e.GameplayRate!.Value;
double nextMean = mean + (currentValue - mean) / count;
sumOfSquares += (currentValue - mean) * (currentValue - nextMean);
mean = nextMean;
}
if (count == 0)
return null;
return 10.0 * Math.Sqrt(sumOfSquares / count);
}
/// <summary>
@ -44,15 +66,5 @@ namespace osu.Game.Rulesets.Scoring
}
private static bool affectsUnstableRate(HitEvent e) => !(e.HitObject.HitWindows is HitWindows.EmptyHitWindows) && e.Result.IsHit();
private static double? standardDeviation(double[] timeOffsets)
{
if (timeOffsets.Length == 0)
return null;
double mean = timeOffsets.Average();
double squares = timeOffsets.Select(offset => Math.Pow(offset - mean, 2)).Sum();
return Math.Sqrt(squares / timeOffsets.Length);
}
}
}

1
osu.sln.DotSettings
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@ -1041,4 +1041,5 @@ private void load()
<s:Boolean x:Key="/Default/UserDictionary/Words/=Unplayed/@EntryIndexedValue">True</s:Boolean>
<s:Boolean x:Key="/Default/UserDictionary/Words/=Unproxy/@EntryIndexedValue">True</s:Boolean>
<s:Boolean x:Key="/Default/UserDictionary/Words/=Unranked/@EntryIndexedValue">True</s:Boolean>
<s:Boolean x:Key="/Default/UserDictionary/Words/=Welford_0027s/@EntryIndexedValue">True</s:Boolean>
<s:Boolean x:Key="/Default/UserDictionary/Words/=Zoomable/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>