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Throughput bench does work on cache miss #591

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Throughput bench does work on cache miss #591

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7b36dd7
dowork
May 18, 2024
331df7d
spread
May 18, 2024
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Merge branch 'main' into users/alexpeck/twork
bitfaster May 28, 2024
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26 changes: 25 additions & 1 deletion BitFaster.Caching.ThroughputAnalysis/ThroughputBenchmark.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -101,7 +101,7 @@ protected override double Run(Stage stage, int iter, int threads, IThroughputBen
void action(int index)
{
long[] samples = config.GetTestData(index);
int func(long x) => (int)x;
int func(long x) => Spread(Spread(Spread(Hash32(x))));

for (int i = 0; i < config.Iterations; i++)
{
Expand Down Expand Up @@ -137,6 +137,30 @@ void action(int index)
// throughput = million ops/sec
return throughput;
}

// https://lemire.me/blog/2018/08/15/fast-strongly-universal-64-bit-hashing-everywhere/
private static readonly long a = 46601;
private static long b = 471486146934863;
private static long c = 7411438065634025597l;

[MethodImpl(MethodImplOptions.NoInlining)]
private static int Hash32(long x)
{
int low = (int)x;
int high = (int)((uint)x >> 32);
return (int)((uint)(a * low + b * high + c) >> 32);
}

[MethodImpl(MethodImplOptions.NoInlining)]
private static int Spread(int x)
{
x ^= (int)((uint)x >> 17);
x = (int)(x * 0xed5ad4bb);
x ^= (int)((uint)x >> 11);
x = (int)(x * 0xac4c1b51);
x ^= (int)((uint)x >> 15);
return x;
}
}

public class UpdateThroughputBenchmark : ThroughputBenchmarkBase
Expand Down