Re: emacs communication with subprocess is slow

[Stephen Leake <stephen_leake@stephe-leake.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> Sorry, I don't understand: Emacs 24.3 would simply deaqdlock in this
> situation, as we have established in bug #18420.  But you say that not
> only does it not hang, it is even faster.  What am I missing?
>
> And what exactly does "large enough" mean here?  What sizes are we
> talking about?
>
> Also, can you quantify the delays?

I submitted bug 18626; see details there.

>> I can use a large buffer in my subprocess for read as a workaround, but
>> I have no control over the read buffer in Emacs (perhaps that could be
>> added?).
>
> You could try playing with 2 parameters that currently are fixed: the
> size of the pipe buffer (set by pipe2 in w32.c, where we use 0 which
> AFAIK defaults to 4KB); and the delay used by send_process in
> process.c when it gets EAGAIN/EWOULDBLOCK from the 'write' call
> (currently 20 milliseconds).

I'll try this and reply in the bug.

--
-- Stephe