From: Michael Albinus via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Suhail Singh <suhailsingh247@gmail.com>, 73046@debbugs.gnu.org
Subject: bug#73046: 29.4; Emacs 100% CPU usage for several seconds when opening dired buffer over TRAMP
Date: Fri, 20 Sep 2024 11:54:28 +0200 [thread overview]
Message-ID: <87bk0ik5uz.fsf@gmx.de> (raw)
In-Reply-To: <86ed5mffbc.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 14 Sep 2024 18:03:19 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
Hi,
> If 3 surprised you, then the reason is simple: sit-for returns
> immediately if any input is available, so typing effectively disables
> the wait. This could be countermanded by unconditional sleep, but
> AFAIU Michael is rethinking the whole issue, so we should wait for him
> to reach his conclusions.
>
> In any case, interrupting the wait when you type makes sense in
> general: it means Emacs is expected to respond sooner, which in most
> cases indeed means to stop waiting immediately.
I played with the different configurations to use sit-for. The test
scenario is simple and can be reproduced with any remote connection, be
it slow or fast:
--8<---------------cut here---------------start------------->8---
emacs -Q /ssh:remotehost:
M-! sleep 30
--8<---------------cut here---------------end--------------->8---
This starts a synchronous remote shell-command, and Tramp must wait for
the response in order to return the exit code (akways 9 in this
scenario). Observe the Emacs resource consumption by 'top' in another shell.
As a second test, I use the Tramp test suite in order to see whether
there is performance degradation. It is sufficient to run the test cases
tramp-test11-copy-file and tramp-test12-rename-file.
make -C test tramp-tests SELECTOR='"11\\|12"'
1. No sit-for call at all, as it has been the case when Suhail reported
the problem.
Emacs consumes 99% .. 100% CPU. The test suite reports
--8<---------------cut here---------------start------------->8---
passed 1/2 tramp-test11-copy-file (1.645027 sec)
passed 2/2 tramp-test12-rename-file (2.172439 sec)
--8<---------------cut here---------------end--------------->8---
2. Use (sit-for 0.005) in `tramp-wait-for-regexp', as done initially
with my patch.
Emacs consumes 42% .. 47% CPU. Good. However, the test suite reports
--8<---------------cut here---------------start------------->8---
passed 1/2 tramp-test11-copy-file (5.311830 sec)
passed 2/2 tramp-test12-rename-file (4.451581 sec)
--8<---------------cut here---------------end--------------->8---
This is a serious performance degradation, which isn't acceptable I
believe.
3. Use (sit-for 0.00005) in `tramp-wait-for-regexp', a much shorter timeout.
Emacs consumes 72% .. 74% CPU. Not ideal, but better than 100%. The test suite reports
--8<---------------cut here---------------start------------->8---
passed 1/2 tramp-test11-copy-file (1.643277 sec)
passed 2/2 tramp-test12-rename-file (1.800990 sec)
--8<---------------cut here---------------end--------------->8---
This is comparable to the initial values (there's always a small
difference).
4. Use (sit-for 0) in `tramp-wait-for-regexp'.
Emacs consumes 72% .. 74% CPU, the same as in 3. The test suite reports
--8<---------------cut here---------------start------------->8---
passed 1/2 tramp-test11-copy-file (1.562353 sec)
passed 2/2 tramp-test12-rename-file (1.626922 sec)
--8<---------------cut here---------------end--------------->8---
Seems to be the best compromise, I'm in the mood to apply.
Comments?
Best regards, Michael.
next prev parent reply other threads:[~2024-09-20 9:54 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-05 14:24 bug#73046: 29.4; Emacs 100% CPU usage for several seconds when opening dired buffer over TRAMP Suhail Singh
2024-09-05 15:56 ` Eli Zaretskii
2024-09-05 21:04 ` Suhail Singh
2024-09-06 5:40 ` Eli Zaretskii
2024-09-06 13:23 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-06 13:54 ` Eli Zaretskii
2024-09-06 14:09 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-06 16:09 ` Eli Zaretskii
2024-09-06 17:47 ` Suhail Singh
2024-09-06 19:08 ` Eli Zaretskii
2024-09-07 0:19 ` Suhail Singh
2024-09-07 1:39 ` Suhail Singh
2024-09-07 6:29 ` Eli Zaretskii
2024-09-07 8:07 ` Suhail Singh
2024-09-07 14:36 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-07 15:07 ` Eli Zaretskii
2024-09-07 17:35 ` Suhail Singh
2024-09-08 11:30 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-08 11:47 ` Eli Zaretskii
2024-09-08 15:26 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-08 15:41 ` Eli Zaretskii
2024-09-08 16:46 ` Suhail Singh
2024-09-08 17:53 ` Eli Zaretskii
2024-09-10 8:10 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-11 1:05 ` Suhail Singh
2024-09-11 11:50 ` Eli Zaretskii
2024-09-11 16:29 ` Suhail Singh
2024-09-11 16:38 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-11 17:25 ` Suhail Singh
2024-09-12 11:48 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-11 14:13 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-11 15:56 ` Suhail Singh
2024-09-13 23:17 ` Suhail Singh
2024-09-14 6:24 ` Eli Zaretskii
2024-09-14 14:25 ` Suhail Singh
2024-09-14 14:41 ` Suhail Singh
2024-09-14 15:03 ` Eli Zaretskii
2024-09-14 22:36 ` Suhail Singh
2024-09-15 5:55 ` Eli Zaretskii
2024-09-15 14:23 ` Suhail Singh
2024-09-20 9:54 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2024-09-20 10:47 ` Eli Zaretskii
2024-09-20 14:18 ` Suhail Singh
2024-09-20 15:35 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-20 15:42 ` Suhail Singh
2024-09-21 8:30 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-21 14:06 ` Suhail Singh
2024-09-14 7:07 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-14 14:39 ` Suhail Singh
2024-09-20 8:48 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-11 14:06 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-07 14:22 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-07 17:58 ` Suhail Singh
2024-09-08 11:26 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-08 15:09 ` Suhail Singh
2024-09-08 15:19 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-08 15:34 ` Suhail Singh
2024-09-08 16:35 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-11 16:19 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-06 16:56 ` Suhail Singh
2024-09-06 16:01 ` Suhail Singh
2024-09-06 15:46 ` Suhail Singh
2024-09-06 15:52 ` Suhail Singh
[not found] <87v7yz1sw8.fsf@rutgers.edu>
2024-09-13 15:47 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-20 16:05 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-20 17:11 ` Jake Nelson via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-09-21 6:59 ` Michael Albinus via Bug reports for GNU Emacs, the Swiss army knife of text editors
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