Use CRC32 hash when available during compression #66
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Motivation ---------- The reference Snappy implementation has switched to this approach to get a performance gain. Modifications ------------- When CRC32C intrinsics are available on x86 or ARM use them to index into the hash table. Also rework the hash operations to use a reference to make it faster to write back to the same location after each step. Results ------- BenchmarkDotNet=v0.13.4, OS=Windows 11 (10.0.22000.1455/21H2) Intel Core i7-10850H CPU 2.70GHz, 1 CPU, 12 logical and 6 physical cores .NET SDK=7.0.200 [Host] : .NET 7.0.3 (7.0.323.6910), X64 RyuJIT AVX2 Job-NOAZVY : .NET 7.0.3 (7.0.323.6910), X64 RyuJIT AVX2 Job-WNHWWN : .NET 6.0.14 (6.0.1423.7309), X64 RyuJIT AVX2 Job-MXBHYC : .NET 7.0.3 (7.0.323.6910), X64 RyuJIT AVX2 Job-AZKGJL : .NET Framework 4.8 (4.8.4614.0), X64 RyuJIT VectorSize=256 | Method | Runtime | PGO | Mean | Error | StdDev | Median | Ratio | RatioSD | Rank | |------- |------------------- |---- |---------:|--------:|--------:|---------:|------:|--------:|-----:| | Legacy | .NET 7.0 | Y | 112.9 us | 1.93 us | 1.81 us | 113.1 us | 1.00 | 0.00 | 2 | | New | .NET 7.0 | Y | 109.6 us | 0.20 us | 0.16 us | 109.6 us | 0.97 | 0.02 | 1 | | | | | | | | | | | | | Legacy | .NET 6.0 | N | 121.8 us | 2.42 us | 2.89 us | 120.7 us | 1.00 | 0.00 | 2 | | New | .NET 6.0 | N | 117.2 us | 2.30 us | 2.56 us | 118.2 us | 0.96 | 0.04 | 1 | | | | | | | | | | | | | Legacy | .NET 7.0 | N | 118.3 us | 2.36 us | 2.62 us | 116.4 us | 1.00 | 0.00 | 1 | | New | .NET 7.0 | N | 116.5 us | 0.18 us | 0.15 us | 116.5 us | 0.99 | 0.02 | 1 | | | | | | | | | | | | | Legacy | .NET Framework 4.8 | N | 210.6 us | 4.15 us | 5.40 us | 210.0 us | 1.00 | 0.00 | 1 | | New | .NET Framework 4.8 | N | 211.5 us | 3.94 us | 4.05 us | 213.2 us | 1.00 | 0.03 | 1 |
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Motivation
The reference Snappy implementation has switched to this approach to get a performance gain.
Modifications
When CRC32C intrinsics are available on x86 or ARM use them to index into the hash table. Also rework the hash operations to use a reference to make it faster to write back to the same location after each step.
Results
BenchmarkDotNet=v0.13.4, OS=Windows 11 (10.0.22000.1455/21H2) Intel Core i7-10850H CPU 2.70GHz, 1 CPU, 12 logical and 6 physical cores .NET SDK=7.0.200
[Host] : .NET 7.0.3 (7.0.323.6910), X64 RyuJIT AVX2
Job-NOAZVY : .NET 7.0.3 (7.0.323.6910), X64 RyuJIT AVX2
Job-WNHWWN : .NET 6.0.14 (6.0.1423.7309), X64 RyuJIT AVX2
Job-MXBHYC : .NET 7.0.3 (7.0.323.6910), X64 RyuJIT AVX2
Job-AZKGJL : .NET Framework 4.8 (4.8.4614.0), X64 RyuJIT VectorSize=256