[Perf] Changes at 11/17/2021 1:35:01 AM

[performanceautofiler]

Run Information

Architecture	arm64
OS	Windows 10.0.19041
Baseline	c66fa996b5cc32d94b2e6a8dfeb7c3d3a3098694
Compare	da0e0f73e24036a88411dde8158df80e5f4bff01
Diff	Diff

Regressions in System.Globalization.Tests.StringSearch

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio	Baseline ETL	Compare ETL
IsPrefix_DifferentFirstChar - Duration of single invocation	8.45 ns	19.29 ns	2.28	0.24	True
IsSuffix_DifferentLastChar - Duration of single invocation	8.25 ns	18.97 ns	2.30	0.24	True

Test Report

Repro

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net6.0 --filter 'System.Globalization.Tests.StringSearch*'

Payloads

Baseline
Compare

Histogram

System.Globalization.Tests.StringSearch.IsPrefix_DifferentFirstChar(Options: (, IgnoreCase, False))

System.Globalization.Tests.StringSearch.IsSuffix_DifferentLastChar(Options: (, None, False))

Docs

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

[ghost]

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

Issue Details

---

Run Information

Architecture	arm64
OS	Windows 10.0.19041
Baseline	c66fa996b5cc32d94b2e6a8dfeb7c3d3a3098694
Compare	da0e0f73e24036a88411dde8158df80e5f4bff01
Diff	Diff

Regressions in System.Globalization.Tests.StringSearch

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio	Baseline ETL	Compare ETL
IsPrefix_DifferentFirstChar - Duration of single invocation	8.45 ns	19.29 ns	2.28	0.24	True
IsSuffix_DifferentLastChar - Duration of single invocation	8.25 ns	18.97 ns	2.30	0.24	True

Test Report

Repro

git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net6.0 --filter 'System.Globalization.Tests.StringSearch*'

Payloads

Baseline
Compare

Histogram

System.Globalization.Tests.StringSearch.IsPrefix_DifferentFirstChar(Options: (, IgnoreCase, False))

System.Globalization.Tests.StringSearch.IsSuffix_DifferentLastChar(Options: (, None, False))

Docs

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

Author:	performanceautofiler[bot]
Assignees:	-
Labels:	area-System.Globalization, untriaged
Milestone:	-

[DrewScoggins]

Seems related to #61640

[safern]

cc: @AaronRobinsonMSFT @jkoritzinsky as it seems related to the DllImport Generator change.

[AaronRobinsonMSFT]

/cc @elinor-fung

[elinor-fung]

Were any of the converted p/invokes in SPCL marshalling strings as ANSI?

[AaronRobinsonMSFT]

@elinor-fung was able to root cause this issue. She will be providing details on her investigation shortly.

[elinor-fung]

Stepped through CompareInfo.IsPrefix and CompareInfo.IsSuffix with the input from the regressed test cases - they are scenarios that do not end up calling any p/invokes, which is actually why they are the ones that regressed.

With #61640, the StartsWith and EndsWith generated stubs and blittable p/invokes are now being inlined into their callers, leading to a p/invoke frame being initialized (JIT_InitPInvokeFrame) even for the scenarios that would not end up invoking it.

Before #61640:

Name                                                                       	Inc %	     Inc	Exc %	   Exc
+ System.Private.CoreLib.il!CompareInfo.IsPrefix                           	 63.6	   4,648	  8.8	   646
|+ System.Private.CoreLib.il!CompareInfo.IcuStartsWith                     	 53.4	   3,899	 22.7	 1,655
||+ System.Private.CoreLib.il!CompareInfo.StartsWithOrdinalIgnoreCaseHelper	 29.6	   2,159	 29.6	 2,159
||+ OTHER <<?!?>>                                                          	  1.2	      84	  1.2	    84

After:

Name                                                                       	Inc %	     Inc	Exc %	   Exc
+ System.Private.CoreLib.il!CompareInfo.IsPrefix                           	 62.1	   4,926	  6.1	   487
|+ System.Private.CoreLib.il!CompareInfo.IcuStartsWith                     	 54.9	   4,355	 15.3	 1,214
||+ System.Private.CoreLib.il!CompareInfo.StartsWithOrdinalIgnoreCaseHelper	 33.5	   2,652	 21.0	 1,666
|||+ coreclr!JIT_InitPInvokeFrame                                          	 12.4	     986	 12.4	   986
||+ coreclr!JIT_InitPInvokeFrame                                           	  6.0	     476	  6.0	   476
||+ OTHER <<?!?>>                                                          	  0.2	      12	  0.2	    12

[AaronRobinsonMSFT]

It appears this is a know case where the JIT can do better. It is described/tracked in #59002.