Move steps to decompress from scratch to a separate method #52
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Motivation ---------- The DecompressAllTags method is overly complicated and the step to decompress from scratch is not a hot path. At most it should be hit once per block when processing a stream and never when processing a block. Modifications ------------- Move the logic to decompress from scratch to a separate method. Slightly optimize the short-circuit logic as well. Results ------- JIT should be able to do a better job of enregistration and preventing register spillage. DecompressAllTags also gets a smaller stack size which may reduce cache misses. We're seeing some minor gains decompressing from streams on .NET 6/7. The gains are within error margins so hard to confirm, they may be more significant on more constrained systems. | Method | Job | Runtime | ReadSize | Mean | Error | StdDev | Median | |----------- |----------------------------- |------------------- |--------- |---------:|--------:|--------:|---------:| | Inline | MediumRun-.NET 6.0 | .NET 6.0 | 16384 | 180.2 us | 1.63 us | 2.40 us | 179.0 us | | MethodCall | MediumRun-.NET 6.0 | .NET 6.0 | 16384 | 179.6 us | 2.15 us | 2.94 us | 178.5 us | | Inline | MediumRun-.NET 7.0 | .NET 7.0 | 16384 | 156.0 us | 2.23 us | 3.19 us | 156.7 us | | MethodCall | MediumRun-.NET 7.0 | .NET 7.0 | 16384 | 155.8 us | 1.55 us | 2.22 us | 155.6 us | | Inline | MediumRun-.NET Framework 4.8 | .NET Framework 4.8 | 16384 | 278.1 us | 1.83 us | 2.57 us | 277.3 us | | MethodCall | MediumRun-.NET Framework 4.8 | .NET Framework 4.8 | 16384 | 280.3 us | 3.59 us | 5.37 us | 281.4 us |
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Motivation
The DecompressAllTags method is overly complicated and the step to decompress from scratch is not a hot path. At most it should be hit once per block when processing a stream and never when processing a block.
Modifications
Move the logic to decompress from scratch to a separate method. Slightly optimize the short-circuit logic as well.
Results
JIT should be able to do a better job of enregistration and preventing register spillage. DecompressAllTags also gets a smaller stack size which may reduce cache misses.
We're seeing some minor gains decompressing from streams on .NET 6/7. The gains are within error margins so hard to confirm, they may be more significant on more constrained systems.