thread-static | 易学教程

How is Java's ThreadLocal implemented under the hood?

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问题 How is ThreadLocal implemented? Is it implemented in Java (using some concurrent map from ThreadID to object), or does it use some JVM hook to do it more efficiently? 回答1: All of the answers here are correct, but a little disappointing as they somewhat gloss over how clever ThreadLocal 's implementation is. I was just looking at the source code for ThreadLocal and was pleasantly impressed by how it's implemented. The Naive Implementation If I asked you to implement a ThreadLocal<T> class

How is Java's ThreadLocal implemented under the hood?

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Is this a thread safe way to initialize a [ThreadStatic]?

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问题 [ThreadStatic] private static Foo _foo; public static Foo CurrentFoo { get { if (_foo == null) { _foo = new Foo(); } return _foo; } } Is the previous code thread safe? Or do we need to lock the method? 回答1: If its ThreadStatic there's one copy per thread. So, by definition, its thread safe. This blog has some good info on ThreadStatic. 回答2: A [ThreadStatic] is compiler/language magic for thread local storage. In other words, it is bound to the thread, so even if there is a context switch it

Using Parallel Extensions with ThreadStatic attribute. Could it leak memory?

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问题 I'm using Parallel Extensions fairly heavily and I've just now encountered a case where using thread local storage might be sensible to allow re-use of objects by worker threads. As such I was looking at the ThreadStatic attribute which marks a static field/variable as having a unique value per thread. It seems to me that it would be unwise to use PE with the ThreadStatic attribute without any guarantee of thread re-use by PE. That is, if threads are created and destroyed to some degree would

Using Parallel Extensions with ThreadStatic attribute. Could it leak memory?

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I'm using Parallel Extensions fairly heavily and I've just now encountered a case where using thread local storage might be sensible to allow re-use of objects by worker threads. As such I was looking at the ThreadStatic attribute which marks a static field/variable as having a unique value per thread. It seems to me that it would be unwise to use PE with the ThreadStatic attribute without any guarantee of thread re-use by PE. That is, if threads are created and destroyed to some degree would the variables (and thus objects they point to) remain in thread local storage for some indeterminate

ThreadStatic Modified with Static C#

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问题 I have some code where I use a thread static object in C#. [ThreadStatic] private DataContext connection I was wondering, in this case, what if any change would I get if I put the static modifier on the thread static context? [ThreadStatic] private static DataContext connection With the first would there be one copy of the context per instance per thread, with the other only one copy per thread? 回答1: The ThreadStaticAttribute is only designed to be used on static variables, as MSDN points out

Will values in my ThreadStatic variables still be there when cycled via ThreadPool?

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I am using ThreadStatic variables to store some data, but I am worried that the data I store on the thread will still be there after I am finished with it and release back to the ThreadPool. Do I need to worry about clearing my ThreadStatic variables before I am finished with the thread? Or will the ThreadPool do this for me before "passing it out" for the next QueueUserWorkItem? This is especially important for me because I need to make sure that other threads in my app have a clean slate to work from in terms of ThreadStatic variables. Thanks! The thread pool (by design) keeps the threads

Will values in my ThreadStatic variables still be there when cycled via ThreadPool?

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问题 I am using ThreadStatic variables to store some data, but I am worried that the data I store on the thread will still be there after I am finished with it and release back to the ThreadPool. Do I need to worry about clearing my ThreadStatic variables before I am finished with the thread? Or will the ThreadPool do this for me before "passing it out" for the next QueueUserWorkItem? This is especially important for me because I need to make sure that other threads in my app have a clean slate to