Thread.GetData/Thread.SetData scalability issue and workaround

This is an internal email from a CLR Developer. I recorded it here just to share the information. I do not work in that area and I can't answer any question.

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The Whidbey
RTM implementation of Thread.GetData/Thread.SetData has several scalability issues
caused by global locks being taken. The appdomain-global lock
taken in LocalDataStore.SetData is one of them. There is another global lock taken in ThreadNative::GetDomainLocalStore that is even worse since it is
process-global.

The best
workaround is to use [ThreadStatic] variables instead of Thread.GetData/Thread.SetData:

       
[ThreadStatic]

       
static Object foo;

[ThreadStatic] variables do not suffer from the contention
issues. Moreover [ThreadStatic] variables are several times faster compared to Thread.GetData/Thread.SetData.