InitializeFlushProcessWriteBuffers() initializes expedited membarrier()
syscall on Linux, which is much slower when called in a multi-thread
process. Move this init earlier to improve dotnet process start time.
A detailed explanation can be found in issue 106722.

Fixes#106722

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Aug 20, 2024

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Aug 20, 2024

membarrier(REGISTER_PRIVATE_EXPEDITED) waits through an unnecessary RCU grace period during Linux process startup#106722

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harisokanovic force-pushed thedev/harisokn/improve-membarrier-init branch from10107a0 to27896a2Compare

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pal init: InitializeFlushProcessWriteBuffers() before first thread to…

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… improve start timeInitializeFlushProcessWriteBuffers() initializes expedited membarrier()syscall on Linux, which is much slower when called in a multi-threadprocess. Move this init earlier to improve dotnet process start time.A detailed explanation can be found in issue 106722.Fixesdotnet#106722

harisokanovic force-pushed thedev/harisokn/improve-membarrier-init branch from27896a2 tobc7dbddCompare

August 21, 2024 19:12

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Looks great! Thank you

Could you please accept the Contributor License Agreement?

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harisokanovic commentedAug 21, 2024

@dotnet-policy-service agree company="Amazon"

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This was referencedAug 21, 2024

System.IO.Net5Compat.Tests and System.IO.Tests suddenly exiting with error 137#100558

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SIGKILL (OOM?) while running LibraryImportGenerator.Tests w/o actionable log messages or artifacts#114241

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harisokanovic commentedAug 21, 2024

The test failures appear to be intermittent per#100558 and#2496. I don't have permission to rerun those jobs.

jkotas merged commit27ee590 intodotnet:main

Aug 22, 2024

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harisokanovic commentedAug 22, 2024

@jkotas, is it possible to backport this change to dotnet8?
CC@Beau-Gosse-dev

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jkotas commentedAug 22, 2024

/backport to release/9.0

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github-actionsbot commentedAug 22, 2024

Started backporting to release/9.0:https://github.com/dotnet/runtime/actions/runs/10514758065

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Aug 22, 2024

[release/9.0] pal init: Init membarrier() before first thread to improve start time#106836

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jkotas commentedAug 22, 2024

is it possible to backport this change to dotnet8?

I can backport it to .NET 9 RC for now.

This change does not meet our default servicing bar. It is a perf fix that is not fixing a regression, the problem existed for number of years since membarrier was introduced. Given that the fix is very simple and it provides measurable improvement for every app, I can ask for an exception for .NET 8 backport after the fix bakes for several months in main and .NET 9.