From: Eli Zaretskii <eliz@gnu.org>
To: stephen_leake@stephe-leake.org
Cc: 18626@debbugs.gnu.org
Subject: bug#18626: 24.3.94; communication with subprocess is slow
Date: Sat, 04 Oct 2014 11:07:14 +0300 [thread overview]
Message-ID: <83oatsgswd.fsf@gnu.org> (raw)
In-Reply-To: <85wq8ge3gr.fsf@stephe-leake.org>
> From: stephen_leake@stephe-leake.org
> Date: Sat, 04 Oct 2014 01:47:16 -0500
>
> (find-file "emacs-24.3.94/src/xdisp.c")
> (pipe-torture "cat.exe")
> => 11.255173
>
> The time varies slightly with each run. "cat.exe" here is from Cygwin.
>
> For comparison, in a Cygwin bash shell on the same system:
>
> $ cd /tmp
> $ time cat < /Projects/emacs/emacs-24.3.94/src/xdisp.c > xdisp.c
> real 0m0.051s
> user 0m0.000s
> sys 0m0.030s
Can you present similar timings from some Posix platform for
comparison?
> Doing (setq process-adaptive-read-buffering nil) did not change the
> timing.
AFAIK, this variable only matters for reading the subprocess output.
Since you didn't present the results for that, there's no evidence yet
which would support this conclusion.
> (pipe-torture "debug.exe" "4096")
> 4.797574
>
> (pipe-torture "debug.exe" "40000")
> 0.523758
>
> The test with "debug.exe" can also be run in Emacs 24.3.1, since it does
> not mix reads and writes (see bug 18420); it gives a time comparable to
> the command-line "cat": 0.053000
That's actually evidence that playing with the 2 parameters mentioned
on emacs-devel might make the time lower.
Still, the question is what happens on GNU/Linux or some other popular
Posix platform, in comparison with Windows. I get ~1.2 sec on one
such machine, which is still a significant slowdown wrt file I/O
outside of Emacs, by a factor of about 50.
> In emacs 24.3.94:
> (pipe-torture-read "/Projects/emacs/emacs-24.3.94/src/xdisp.c")
> "read time 11.965184"
>
> In Windows native emacs 24.3.1:
> (pipe-torture-read "/Projects/emacs/emacs-24.3.94/src/xdisp.c")
> "read time 11.992000"
That's identical, and expected: the changeset that solved the deadlock
case only changes the way Emacs treats the write end of the pipe. The
read end behaves in Emacs 24.4 identically to what it did in 24.3.
next prev parent reply other threads:[~2014-10-04 8:07 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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=83oatsgswd.fsf@gnu.org \
--to=eliz@gnu.org \
--cc=18626@debbugs.gnu.org \
--cc=stephen_leake@stephe-leake.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.