[Perf] Windows/x64: 17 Regressions on 7/22/2025 8:52:00 PM +00:00

[performanceautofiler]

Run Information

Name	Value
Architecture	x64
OS	Windows 10.0.22631
Queue	ViperWindows
Baseline	2e4770f686731a50e50bffb980ea5cbc4cac6ce5
Compare	b306971348daefc65862fc446272a832b17aa71f
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	34.89 μs	38.22 μs	1.10	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	41.01 μs	44.60 μs	1.09	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	38.74 μs	42.62 μs	1.10	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	39.15 μs	42.66 μs	1.09	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	34.76 μs	38.34 μs	1.10	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	34.82 μs	38.28 μs	1.10	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	39.30 μs	43.05 μs	1.10	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	59.39 μs	64.27 μs	1.08	0.39	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock*'

Details

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "aqj", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "Sherlock\s+Holmes", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "(?m)^Sherlock Holmes|Sherlock Holmes$", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "Sherlock Holmes", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "aei", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "zqj", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "Sherlock", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_RustLang_Sherlock.Count(Pattern: "The", Options: Compiled)

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JIT Disasms

Docs

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

---

Run Information

Name	Value
Architecture	x64
OS	Windows 10.0.22631
Queue	ViperWindows
Baseline	2e4770f686731a50e50bffb980ea5cbc4cac6ce5
Compare	b306971348daefc65862fc446272a832b17aa71f
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Text.RegularExpressions.Tests.Perf_Regex_Industry_Leipzig

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	1.13 ms	1.23 ms	1.09	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	1.02 ms	1.11 ms	1.09	0.00	False
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	1.14 ms	1.23 ms	1.08	0.00	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.RegularExpressions.Tests.Perf_Regex_Industry_Leipzig*'

Details

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_Leipzig.Count(Pattern: "(?i)Twain", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_Leipzig.Count(Pattern: "Twain", Options: Compiled)

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JIT Disasms

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_Leipzig.Count(Pattern: "[a-z]shing", Options: Compiled)

ETL Files

Histogram

JIT Disasms

Docs

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

---

Run Information

Name	Value
Architecture	x64
OS	Windows 10.0.22631
Queue	ViperWindows
Baseline	2e4770f686731a50e50bffb980ea5cbc4cac6ce5
Compare	b306971348daefc65862fc446272a832b17aa71f
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Memory.Span<Char>

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
IndexOfAnyTwoValues - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	12.00 ns	13.24 ns	1.10	0.08	False
IndexOfAnyFiveValues - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	24.93 ns	27.22 ns	1.09	0.14	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span<Char>*'

Details

System.Memory.Span<Char>.IndexOfAnyTwoValues(Size: 512)

ETL Files

Histogram

JIT Disasms

System.Memory.Span<Char>.IndexOfAnyFiveValues(Size: 512)

ETL Files

Histogram

JIT Disasms

Docs

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

---

Run Information

Name	Value
Architecture	x64
OS	Windows 10.0.22631
Queue	ViperWindows
Baseline	2e4770f686731a50e50bffb980ea5cbc4cac6ce5
Compare	b306971348daefc65862fc446272a832b17aa71f
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Text.RegularExpressions.Tests.Perf_Regex_Industry_SliceSlice

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
Count - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	343.79 ms	375.38 ms	1.09	0.00	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.RegularExpressions.Tests.Perf_Regex_Industry_SliceSlice*'

Details

System.Text.RegularExpressions.Tests.Perf_Regex_Industry_SliceSlice.Count(Options: Compiled)

ETL Files

Histogram

JIT Disasms

Docs

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

---

Run Information

Name	Value
Architecture	x64
OS	Windows 10.0.22631
Queue	ViperWindows
Baseline	2e4770f686731a50e50bffb980ea5cbc4cac6ce5
Compare	b306971348daefc65862fc446272a832b17aa71f
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Memory.Span<Byte>

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
IndexOfAnyFourValues - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	11.00 ns	13.19 ns	1.20	0.27	False
IndexOfAnyFiveValues - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	12.93 ns	19.14 ns	1.48	0.16	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span<Byte>*'

Details

System.Memory.Span<Byte>.IndexOfAnyFourValues(Size: 512)

ETL Files

Histogram

JIT Disasms

System.Memory.Span<Byte>.IndexOfAnyFiveValues(Size: 512)

ETL Files

Histogram

JIT Disasms

Docs

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

---

Run Information

Name	Value
Architecture	x64
OS	Windows 10.0.22631
Queue	ViperWindows
Baseline	2e4770f686731a50e50bffb980ea5cbc4cac6ce5
Compare	b306971348daefc65862fc446272a832b17aa71f
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Text.RegularExpressions.Tests.Perf_Regex_Common

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
MatchesWord - Duration of single invocation 📝 - Benchmark Source ADX - Test Multi Config Graph	639.91 ns	698.28 ns	1.09	0.06	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.RegularExpressions.Tests.Perf_Regex_Common*'

Details

System.Text.RegularExpressions.Tests.Perf_Regex_Common.MatchesWord(Options: Compiled)

ETL Files

Histogram

JIT Disasms

Docs

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

[LoopedBard3]

Most likely #117887 in range b131b6d...8fac1c5. FYI @tannergooding. Related Regressions:

• [Perf] Linux/x64: 5 Regressions on 7/22/2025 8:52:00 PM +00:00 perf-autofiling-issues#59781

[tannergooding]

None of these have regressed compared to net9 and many are still a bit faster. Most of the regressions are a couple of ns, one larger benchmark is a handful of microseconds

I’d suggest just closing this as we knew there may be some micro-architecture specific regressions. The long term fix is to avoid the back and forth when doing the kortest, which we’ll get to in dotnet 11

[dotnet-policy-service]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

[JulieLeeMSFT]

Closing this issue per Tanner's analysis.

[stephentoub]

None of these have regressed compared to net9 and many are still a bit faster.

But the improvements this counteracts were hard-won performance improvements in a completely unrelated part of the code, right? e.g. #108365

Some of these regressions are 10% and measured in microseconds, not nanoseconds.

Feels premature to just close this outright.