From: Stephen Leake <stephen_leake@stephe-leake.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 18626@debbugs.gnu.org
Subject: bug#18626: 24.3.94; communication with subprocess is slow
Date: Fri, 10 Oct 2014 03:47:12 -0500 [thread overview]
Message-ID: <85h9zcux9r.fsf@stephe-leake.org> (raw)
In-Reply-To: <85r3ymcr0u.fsf@stephe-leake.org> (Stephen Leake's message of "Sun, 05 Oct 2014 13:25:53 -0500")
There remains a problem on Linux; with either a pty or a pipe, there is
a default internal buffer of 2^16 bytes, which means we encounter the
send_process EWOULDBLOCK delay of 20 ms for every 2^16 bytes; that takes
0.3 seconds for 1 megabyte:
(find-file "xdisp.c")
(pipe-torture
"/home/Projects/org.emacs.ada-mode.stephe-1/build/wisi/debug_counted"
"974233" "974233")
send time 0.291322
The pipe is created by emacs_pipe in sysdep.c; there is no parameter for
the internal buffer size.
The pty is created by allocate_pty in process.c; I don't see a size
parameter there, but there are lots of macros.
However, changing the value for the nsecs parameter in the call to
wait_reading_process_output in send_process at process.c:4282 has no
effect, so the 20 ms delay is coming from something else.
--
-- Stephe
prev parent reply other threads:[~2014-10-10 8:47 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-04 6:47 bug#18626: 24.3.94; communication with subprocess is slow stephen_leake
2014-10-04 8:07 ` Eli Zaretskii
2014-10-05 13:20 ` Stephen Leake
2014-10-05 13:41 ` Stephen Leake
2014-10-05 14:43 ` Eli Zaretskii
2014-10-05 18:19 ` Stephen Leake
2014-10-04 8:11 ` Stephen Leake
2014-10-04 8:32 ` Eli Zaretskii
2014-10-04 22:29 ` Stefan Monnier
2014-10-05 2:46 ` Eli Zaretskii
2014-10-05 13:34 ` Stephen Leake
2014-10-05 14:40 ` Eli Zaretskii
2014-10-05 18:25 ` Stephen Leake
2014-10-05 19:04 ` Eli Zaretskii
2014-10-08 13:29 ` Stephen Leake
2014-10-08 13:53 ` Eli Zaretskii
2014-10-10 8:07 ` Stephen Leake
2014-10-10 9:13 ` Eli Zaretskii
2014-10-10 8:47 ` Stephen Leake [this message]
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