What is reason 8 for ThreadPoolWorkerThreadAdjustmentAdjustment event?

[xiaomi7732]

EventPipe captured thread adjustment event with reason 8:

According to this document, there are listed reasons from 0x00 to 0x07: https://docs.microsoft.com/en-us/dotnet/framework/performance/thread-pool-etw-events#threadpoolworkerthreadadjustmentadjustment

Do we know what does 0x08 means?

I also don't see an enum for the reason in the runtime repo:

Refer to this Runtime code Am I looking into the right place?

Thanks!

[brianrob]

0x8 is CooperativeBlocking. This should be specific to .NET Core.

The parser has been updated with this value at https://github.com/microsoft/perfview/blob/main/src/TraceEvent/Parsers/ClrTraceEventParser.cs#L12873.

[xiaomi7732]

Hey @brianrob Thanks for the quick turn-around. What does CooperativeBlocking mean? Do you have any documentation to help understand it? It will also be great if there's any documentation to explain other reasons in the enum too. Thanks!

[brianrob]

CooperativeBlocking is a behavior that allows the threadpool to detect behavior that looks like sync-over-async and increase the rate of thread injection to avoid thread starvation.

[xiaomi7732]

Makes sense. Thanks for the info.