Cells get executed using different threads

Cells get executed using different threads

This is a design question and a possible bug.

As you execute different cells in a C# or F# notebook, a different thread gets used for each interaction. The question is really whether we want to guarantee that the same thread gets used each time you execute a new cell. Since cell execution is inherently linear it feels we should likely guarantee this.

For example, repeated re-execution of

System.Console.WriteLine("{0}", System.Threading.Thread.CurrentThread.ManagedThreadId);

gives 10, 11 etc.

This came up when using TensorFlow.NET, which had some thread local storage that was not getting re-initialized correctly as operations were performed from different threads. But the question is more general too - is is something we want to guarantee or not, and we should document it either way.

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[lostmsu]

Either I am misunderstanding something, or library code should not be affected. All new tasks started from interactive should use standard SynchronizationContext and can execute on any worker thread. Single thread should only affect the top-level call.

[dsyme]

So I’m not suggesting changing how TensorFlow or other libraries work, but rather adding kernel extensions to their NuGet packages that customize the behavior of .NET Interactive’s threading model in the presence of those libraries.

I don’t think this is realistic. The TensorFlow threading model is not particularly strange and it’s not possible to go round patching up the package ecosystem to include dependencies on .NET Interactive

We should just make it possible to configure .NET Interactive to respect a single-threaded execution model without any changes to package ecosystems. A magic command would be enough.

@lostmsu We should work together to get a proposed fix for this I think.