System.Reactive choosing between Scheduler.Default and TaskPoolScheduler.Default

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I'm having significant difficulty choosing between Scheduler.Default and TaskPoolScheduler.Default.

I've seen it suggested that the TaskPoolScheduler is more efficient/optimised and it certainly has the benefit of being more explicit/specific; however, that doesn't help me understand the real differences, given that functionally they appear to do the same thing.

When is Scheduler.Default preferable to TaskPoolScheduler.Default and vice versa?

system.reactive .net-core
1 Answers

Scheduler.Default is the same as DefaultScheduler.Instance.

How does the DefaultScheduler handle thunks? DefaultScheduler sits on top of a platform abstraction layer that schedules work depending on what system it's on.

This used to be the System.Reactive.PlatformServices.dll assembly, which would differ according to the plaform, but for 4.x it's just an empty facade assembly to stay compatible with 3.x, with the implementation moved to System.Reactive.dll.

For DefaultScheduler:

  • As of now, for scheduling immediate work, the ThreadPool is used.
  • For periodic events (SchedulePeriodic) a System.Threading.Timer is used.
  • For work which runs as fast as possible, a new thread is used.

The details of what platform service is chosen is in the EnlightenmentProvider.

You could maybe use DefaultScheduler when you have long-running computations or periodic events where TimeSpan is very small, or zero, although EventLoopScheduler may be better.

Prefer TaskPoolScheduler when possible. It's a lightweight implementation intended for short computations.

user_8021160
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