Module `In_thread.When_finished`

When_finished describes how In_thread.run f behaves when the helper thread finishes f ().

type t = | Notify_the_scheduler The helper thread notifies the Async scheduler that the result is ready, so that the scheduler will wake up in a timely manner and run a cycle. | Take_the_async_lock The helper thread blocks until it can acquire the Async lock, at which point it runs a cycle. | Try_to_take_the_async_lock If the thread_pool_cpu_affinity is Inherit, then the helper hread tries to take the Async lock and run a cycle. If the thread_pool_cpu_affinity is Cpuset or the helper thread is unable to acquire the Async lock, then it behaves as in Notify_the_scheduler.

val default : t Core.ref: default defines the default value used for In_thread.run's ?when_finished argument. Changes to default affect subsequent calls to In_thread.run. Initially, default = Try_to_take_the_async_lock, which typically leads to better latency by avoiding an extra context switch to pass the result to the Async scheduler thread. However, there are applications (e.g. jenga) where Notify_the_scheduler leads to significantly higher throughput by greatly decreasing the total number of Async cycles.

`\|` `Notify_the_scheduler`	The helper thread notifies the Async scheduler that the result is ready, so that the scheduler will wake up in a timely manner and run a cycle.
`\|` `Take_the_async_lock`	The helper thread blocks until it can acquire the Async lock, at which point it runs a cycle.
`\|` `Try_to_take_the_async_lock`	If the `thread_pool_cpu_affinity` is `Inherit`, then the helper hread tries to take the Async lock and run a cycle. If the `thread_pool_cpu_affinity` is `Cpuset` or the helper thread is unable to acquire the Async lock, then it behaves as in `Notify_the_scheduler`.