[erlang-questions] ready_async() before outputv() calling driver_async() completes?

Raimo Niskanen <>
Thu Oct 16 09:29:32 CEST 2008


On Wed, Oct 15, 2008 at 06:08:31PM -0500, Paul Fisher wrote:
> Should it be possible for a ready_async() callback to happen before the 
> outputv() callback which called driver_async() has returned?  I am 
> seeing this happen on R12B-2 smp runtime (2 schedulers), w/four (4) 
> async threads.

For a non-SMP emulator ready_async() is called by driver_async(),
so then the call to ready_async() certainly happens before
the return of outputv(), so the SMP emulator should could
take the liberty to do the same.

And even if the SMP emulator does not do it explicitly, 
it is always possible for the thread calling outputv()
to get scheduled out between the return from driver_async()
and the return from outputv(), and the asynchronous
thread to get scheduled in, do its thing and call ready_async()
right then.

> 
> 
> --
> paul
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-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB



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