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Merged
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Jun 14, 2020
Merged

count once #24

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2 changes: 1 addition & 1 deletion BitFaster.Caching.Benchmarks/Program.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ class Program
static void Main(string[] args)
{
var summary = BenchmarkRunner
.Run<LruCycle2>(ManualConfig.Create(DefaultConfig.Instance)
.Run<MissHitHitRemove>(ManualConfig.Create(DefaultConfig.Instance)
.AddJob(Job.RyuJitX64));
}
}
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13 changes: 5 additions & 8 deletions BitFaster.Caching.UnitTests/Lru/HitCounterTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,20 +13,19 @@ public class HitCounterTests
public void WhenHitCountAndTotalCountAreEqualRatioIs1()
{
HitCounter counter = new HitCounter();
counter.IncrementTotalCount();
counter.IncrementHitCount();

counter.IncrementHit();

counter.HitRatio.Should().Be(1.0);
}

[Fact]
public void WhenHitCountIsHalfTotalCountRatioIsHalf()
public void WhenHitCountIsEqualToMissCountRatioIsHalf()
{
HitCounter counter = new HitCounter();

counter.IncrementTotalCount();
counter.IncrementTotalCount();
counter.IncrementHitCount();
counter.IncrementMiss();
counter.IncrementHit();

counter.HitRatio.Should().Be(0.5);
}
Expand All @@ -36,8 +35,6 @@ public void WhenTotalCountIsZeroRatioReturnsZero()
{
HitCounter counter = new HitCounter();

counter.IncrementHitCount();

counter.HitRatio.Should().Be(0.0);
}
}
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4 changes: 2 additions & 2 deletions BitFaster.Caching.UnitTests/Lru/NullHitCounterTests.cs
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Expand Up @@ -20,13 +20,13 @@ public void HitRatioIsZero()
[Fact]
public void IncrementHitCountIsNoOp()
{
counter.Invoking(c => c.IncrementHitCount()).Should().NotThrow();
counter.Invoking(c => c.IncrementHit()).Should().NotThrow();
}

[Fact]
public void IncrementTotalCountIsNoOp()
{
counter.Invoking(c => c.IncrementTotalCount()).Should().NotThrow();
counter.Invoking(c => c.IncrementMiss()).Should().NotThrow();
}
}
}
16 changes: 9 additions & 7 deletions BitFaster.Caching/Lru/HitCounter.cs
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Expand Up @@ -10,19 +10,21 @@ namespace BitFaster.Caching.Lru
{
public struct HitCounter : IHitCounter
{
private long requestHitCount;
private long requestTotalCount;
private long hitCount;
private long missCount;

public double HitRatio => requestTotalCount == 0 ? 0 : (double)requestHitCount / (double)requestTotalCount;
public double HitRatio => Total == 0 ? 0 : (double)hitCount / (double)Total;

public void IncrementTotalCount()
public long Total => this.hitCount + this.missCount;

public void IncrementMiss()
{
Interlocked.Increment(ref this.requestTotalCount);
Interlocked.Increment(ref this.missCount);
}

public void IncrementHitCount()
public void IncrementHit()
{
Interlocked.Increment(ref this.requestHitCount);
Interlocked.Increment(ref this.hitCount);
}
}
}
4 changes: 2 additions & 2 deletions BitFaster.Caching/Lru/IHitCounter.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,9 @@ namespace BitFaster.Caching.Lru
{
public interface IHitCounter
{
void IncrementTotalCount();
void IncrementMiss();

void IncrementHitCount();
void IncrementHit();

double HitRatio { get; }
}
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4 changes: 2 additions & 2 deletions BitFaster.Caching/Lru/NullHitCounter.cs
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Expand Up @@ -12,12 +12,12 @@ public struct NullHitCounter : IHitCounter
public double HitRatio => 0.0;

[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void IncrementTotalCount()
public void IncrementMiss()
{
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void IncrementHitCount()
public void IncrementHit()
{
}
}
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9 changes: 4 additions & 5 deletions BitFaster.Caching/Lru/TemplateConcurrentLru.cs
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Expand Up @@ -94,8 +94,6 @@ public TemplateConcurrentLru(

public bool TryGet(K key, out V value)
{
this.hitCounter.IncrementTotalCount();

I item;
if (dictionary.TryGetValue(key, out item))
{
Expand All @@ -108,11 +106,12 @@ public bool TryGet(K key, out V value)

value = item.Value;
this.policy.Touch(item);
this.hitCounter.IncrementHitCount();
this.hitCounter.IncrementHit();
return true;
}

value = default(V);
this.hitCounter.IncrementMiss();
return false;
}

Expand All @@ -124,7 +123,7 @@ public V GetOrAdd(K key, Func<K, V> valueFactory)
}

// The value factory may be called concurrently for the same key, but the first write to the dictionary wins.
// This is identical logic to the ConcurrentDictionary.GetOrAdd method.
// This is identical logic in ConcurrentDictionary.GetOrAdd method.
var newItem = this.policy.CreateItem(key, valueFactory(key));

if (this.dictionary.TryAdd(key, newItem))
Expand All @@ -146,7 +145,7 @@ public async Task<V> GetOrAddAsync(K key, Func<K, Task<V>> valueFactory)
}

// The value factory may be called concurrently for the same key, but the first write to the dictionary wins.
// This is identical logic to the ConcurrentDictionary.GetOrAdd method.
// This is identical logic in ConcurrentDictionary.GetOrAdd method.
var newItem = this.policy.CreateItem(key, await valueFactory(key).ConfigureAwait(false));

if (this.dictionary.TryAdd(key, newItem))
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33 changes: 16 additions & 17 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -43,32 +43,31 @@ Cache contains 6 items which are fetched repeatedly, no items are evicted. Repre

FastConcurrentLru does not allocate and is approximately 10x faster than MemoryCache.

| Method | Mean | Error | StdDev | Ratio | Gen 0 | Allocated |
|----------------------------- |----------:|---------:|---------:|------:|-------:|----------:|
| ConcurrentDictionaryGetOrAdd | 18.72 ns | 0.289 ns | 0.641 ns | 1.00 | - | - |
| FastConcurrentLruGetOrAdd | 25.64 ns | 0.434 ns | 0.427 ns | 1.35 | - | - |
| ConcurrentLruGetOrAdd | 35.53 ns | 0.259 ns | 0.216 ns | 1.86 | - | - |
| FastConcurrentTLruGetOrAdd | 132.75 ns | 1.493 ns | 1.397 ns | 6.96 | - | - |
| ConcurrentTLruGetOrAdd | 144.87 ns | 2.179 ns | 1.819 ns | 7.59 | - | - |
| ClassicLruGetOrAdd | 75.67 ns | 1.513 ns | 1.554 ns | 3.99 | - | - |
| MemoryCacheGetStringKey | 309.14 ns | 2.155 ns | 1.910 ns | 16.17 | 0.0153 | 32 B |
| Method | Mean | Error | StdDev | Ratio | Gen 0 | Allocated |
|--------------------- |----------:|---------:|---------:|------:|-------:|----------:|
| ConcurrentDictionary | 15.83 ns | 0.242 ns | 0.215 ns | 1.00 | - | - |
| FastConcurrentLru | 20.42 ns | 0.319 ns | 0.283 ns | 1.29 | - | - |
| ConcurrentLru | 24.59 ns | 0.484 ns | 0.594 ns | 1.56 | - | - |
| FastConcurrentTLru | 110.76 ns | 0.664 ns | 0.518 ns | 6.98 | - | - |
| ConcurrentTLru | 114.99 ns | 1.652 ns | 1.465 ns | 7.27 | - | - |
| ClassicLru | 69.01 ns | 0.503 ns | 0.446 ns | 4.36 | - | - |
| MemoryCache | 257.83 ns | 4.786 ns | 4.700 ns | 16.30 | 0.0153 | 32 B |

### Mixed workload

Tests 4 operations, 1 miss (adding the item), 2 hits then remove.

This test needs to be improved to provoke queue cycling.


| Method | Mean | Error | StdDev | Ratio | Gen 0 | Allocated |
|--------------------- |-----------:|---------:|---------:|------:|-------:|----------:|
| ConcurrentDictionary | 178.1 ns | 1.47 ns | 1.23 ns | 1.00 | 0.0381 | 80 B |
| FastConcurrentLru | 420.4 ns | 7.52 ns | 6.67 ns | 2.36 | 0.0534 | 112 B |
| ConcurrentLru | 423.7 ns | 3.17 ns | 2.64 ns | 2.38 | 0.0534 | 112 B |
| FastConcurrentTlru | 941.6 ns | 6.69 ns | 5.93 ns | 5.29 | 0.0572 | 120 B |
| ConcurrentTlru | 960.3 ns | 17.73 ns | 14.80 ns | 5.39 | 0.0572 | 120 B |
| ClassicLru | 363.5 ns | 3.65 ns | 3.23 ns | 2.04 | 0.0763 | 160 B |
| MemoryCache | 2,380.9 ns | 33.22 ns | 27.74 ns | 13.37 | 2.3460 | 4912 B |
| ConcurrentDictionary | 151.7 ns | 2.34 ns | 1.96 ns | 1.00 | 0.0381 | 80 B |
| FastConcurrentLru | 369.2 ns | 7.29 ns | 7.16 ns | 2.44 | 0.0534 | 112 B |
| ConcurrentLru | 373.6 ns | 2.97 ns | 2.64 ns | 2.46 | 0.0534 | 112 B |
| FastConcurrentTlru | 838.6 ns | 11.49 ns | 13.68 ns | 5.53 | 0.0572 | 120 B |
| ConcurrentTlru | 852.7 ns | 16.12 ns | 13.46 ns | 5.62 | 0.0572 | 120 B |
| ClassicLru | 347.3 ns | 2.67 ns | 2.08 ns | 2.29 | 0.0763 | 160 B |
| MemoryCache | 1,987.5 ns | 38.29 ns | 57.31 ns | 13.15 | 2.3460 | 4912 B |


### LruCycle2
Expand Down