[ruby-core:88143] Re: [Ruby trunk Feature#14717] [PATCH] thread: allow disabling preempt

[e-mail] wrote:
> Is this the same as `Thread.new { Thread.handle_interrupt(Exception => :never) { ... } }`?
> What's the difference?

No, current thread switching does not use interrupts in the same
sense (no Exception objects are created).  However, I suppose it
could be implemented internally using ec->interrupt_mask.

> Is preemption as in threads giving control (and the GIL) to
> another is still possible with `Thread#preemptible = true` or
> not?  If not, then I think this feature requires a GIL to be
> implemented (because `Thread#preemptible = true` is called
> after Thread creation) and I am very strongly against it.

Giving control to other threads still happens with Thread.pass
or anything which currently releases GVL (including IO#read,
File.open, etc...).

For platforms without GVL, it can be a no-op.  I understand why
this can be a bad feature from that perspective (I hate GVL, too).
I mainly wanted this feature to give equivalance for
proposed auto-Fiber [Feature #13618] behavior.

Also, maybe disabling preempt less important since I am redoing
[Misc #14937] to eliminate timer-thread completely for pthreads
platforms; so there won't be a need to spawn extra threads even
under contention.

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