[Perf] Regressions in System.IO.Tests.Perf_FileStream

[DrewScoggins]

Run Information

Architecture	x64
OS	Windows 10.0.18362
Baseline	ec2712962d0117dfdca7738ae20f0ce3483eab67
Compare	3c4d419ffe074ab62ff25a75e4127dbe7c9ee2ab
Diff	Diff

Regressions in System.IO.Tests.Perf_FileStream

Benchmark	Baseline	Test	Test/Base	Test Quality	Baseline IR	Compare IR	IR Ratio	Baseline ETL	Compare ETL
SeekForward - Duration of single invocation	30.62 μs	32.28 μs	1.05	0.11
SeekBackward - Duration of single invocation	33.06 μs	37.85 μs	1.14	0.11

Historical Data in Reporting System

Repro

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f netcoreapp5.0 --filter 'System.IO.Tests.Perf_FileStream*'

Payloads

Baseline
Compare

Histogram

System.IO.Tests.Perf_FileStream.SeekForward(fileSize: 1024, options: None)

System.IO.Tests.Perf_FileStream.SeekBackward(fileSize: 1024, options: None)

Docs

Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository

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Issue Details

---

Run Information

Architecture	x64
OS	Windows 10.0.18362
Baseline	ec2712962d0117dfdca7738ae20f0ce3483eab67
Compare	3c4d419ffe074ab62ff25a75e4127dbe7c9ee2ab
Diff	Diff

Regressions in System.IO.Tests.Perf_FileStream

Benchmark	Baseline	Test	Test/Base	Test Quality	Baseline IR	Compare IR	IR Ratio	Baseline ETL	Compare ETL
SeekForward - Duration of single invocation	30.62 μs	32.28 μs	1.05	0.11
SeekBackward - Duration of single invocation	33.06 μs	37.85 μs	1.14	0.11

Historical Data in Reporting System

Repro

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f netcoreapp5.0 --filter 'System.IO.Tests.Perf_FileStream*'

Payloads

Baseline
Compare

Histogram

System.IO.Tests.Perf_FileStream.SeekForward(fileSize: 1024, options: None)

System.IO.Tests.Perf_FileStream.SeekBackward(fileSize: 1024, options: None)

Docs

Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository

Author:	DrewScoggins
Assignees:	-
Labels:	arch-x64, area-System.IO, os-windows, tenet-performance, tenet-performance-benchmarks, untriaged
Milestone:	-

[DrewScoggins]

Seems likely related to #53669

[adamsitnik]

I've taken a look at the source code and the profiles and there is very little we can do about the current implementation (my current best idea would get rid of two virtual method invocations which is not a lot).

Since overall this benchmark is more than 20 times faster than .NET 5 and this method (FileStream.Seek) should never be on a hot path, I believe that it's OK to accept this regression.