[erlang-questions] Synchronous communication with prim_file port

[Lukas Larsson]

Hello,

On Mon, Oct 23, 2017 at 2:35 PM, Salikhov Dinislam <
Dinislam.Salikhov@REDACTED> wrote:

> Is there any rationale for write operation being done this way?
> I'd like to propose an optimization here: if we know in advance that
> standard drv_get_response/1 will be used to get driver's response, then we
> can use synchronous erlang:port_control/3 instead to avoid the whole
> message queue traverse.


Using erlang:port_control/3 will not help as the file I/O job is scheduled
on the async thread poll which means that it has to ack by sending a
message.

We are in the process of re-writing the efile driver for OTP 21 using a
nif, this re-write will solve this problem as no message passing is needed
when ack:ing writes done on dirty schedulers.
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