[Perf] Regressions in System.Text.Perf_Utf8Encoding for Greek and Cyrillic

[DrewScoggins]

Run Information

Architecture	x64
OS	Windows 10.0.18362
Baseline	508e56025f66f5c2c00a8f1902816959bb61e0ac
Compare	65bcecebde4aebd5926952ccfc4dc8e7fbf7eaed
Diff	Diff

Regressions in System.Text.Perf_Utf8Encoding

Benchmark	Baseline	Test	Test/Base	Test Quality	Baseline IR	Compare IR	IR Ratio	Baseline ETL	Compare ETL
GetString - Duration of single invocation	348.09 μs	381.20 μs	1.10	0.00
GetString - Duration of single invocation	223.28 μs	240.51 μs	1.08	0.00
GetBytes - Duration of single invocation	204.86 μs	217.86 μs	1.06	0.01
GetBytes - Duration of single invocation	126.23 μs	139.66 μs	1.11	0.01

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.Text.Perf_Utf8Encoding*'

Details

Payloads

Baseline
Compare

Histogram

System.Text.Perf_Utf8Encoding.GetString(Input: Greek)

System.Text.Perf_Utf8Encoding.GetString(Input: Cyrillic)

System.Text.Perf_Utf8Encoding.GetBytes(Input: Greek)

System.Text.Perf_Utf8Encoding.GetBytes(Input: Cyrillic)

Docs

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Benchmarking workflow for dotnet/runtime repository

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Issue Details

---

Run Information

Architecture	x64
OS	Windows 10.0.18362
Baseline	508e56025f66f5c2c00a8f1902816959bb61e0ac
Compare	65bcecebde4aebd5926952ccfc4dc8e7fbf7eaed
Diff	Diff

Regressions in System.Text.Perf_Utf8Encoding

Benchmark	Baseline	Test	Test/Base	Test Quality	Baseline IR	Compare IR	IR Ratio	Baseline ETL	Compare ETL
GetString - Duration of single invocation	348.09 μs	381.20 μs	1.10	0.00
GetString - Duration of single invocation	223.28 μs	240.51 μs	1.08	0.00
GetBytes - Duration of single invocation	204.86 μs	217.86 μs	1.06	0.01
GetBytes - Duration of single invocation	126.23 μs	139.66 μs	1.11	0.01

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.Text.Perf_Utf8Encoding*'

Details

Payloads

Baseline
Compare

Histogram

System.Text.Perf_Utf8Encoding.GetString(Input: Greek)

System.Text.Perf_Utf8Encoding.GetString(Input: Cyrillic)

System.Text.Perf_Utf8Encoding.GetBytes(Input: Greek)

System.Text.Perf_Utf8Encoding.GetBytes(Input: Cyrillic)

Docs

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

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

[alexcovington]

From @L2:

Regarding System.Text.Perf_Utf8Encoding.GetBytes(Input: Cyrillic)
The regression seems to happen from this commit:
JIT: revise inlinee scale computations #51593
Commit: a4b0a03
PR: #51593
It largely affects this method's assembly (code blocks are moved around):
System.Text.Unicode.Utf8Utility.TranscodeToUtf8(Char*, Int32, Byte*, Int32, Char* ByRef, Byte* ByRef)
Source: https://github.com/dotnet/runtime/blob/main/src/libraries/System.Private.CoreLib/src/System/Text/Unicode/Utf8Utility.Transcoding.cs#L842
The assemblies for this method are identical in Checked Mode but different in Release Mode. Trying to perform a jitdump using Release Mode crashes the jitdump.
(Building in Release and Checked -> copying over the Checked crljit.dll into Release -> using Release with env var COMPlus_JitDump:TranscodeToUtf8
On the same note, I've also experienced the Debug Mode jitdump crash for this particular method at this commit (multiple assert failures).

[eiriktsarpalis]

cc @AndyAyersMS

[danmoseley]

Thanks @alexcovington