GNU bug report logs - #22305
24.5; permanent 100% CPU load for no apparent reason

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 22305 in the body.
You can then email your comments to 22305 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: "Roland Winkler" <winkler <at> gnu.org>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.5; permanent 100% CPU load for no apparent reason
Date: Mon, 4 Jan 2016 10:48:02 -0600

Lately emacs gives me some strange problem, where according to `top'
the CPU load due to the emacs process goes up to a permanent value
of 100% (and I notice this because the laptop fan starts spinning
loudly), whereas according to `ps' the emacs process continues to
give rise to only a marginal CPU load.  While this happens, emacs
responds normally, so it appears that emacs is not trying to do
anything unusual in the background.

I did not have this problem while I was using emacs 24.5 under
ubuntu 14.04.  It only appeared lately when I upgraded to a new
laptop running ubuntu 15.10.  I am not aware of any significant
change in my emacs configuration since I made this switch.

What can I do to pin this down further?  So far, I have not noticed
anything that triggers this behavior reproducibly and my workaround
has been to restart emacs.  But that's not nice for a recurring
problem (about once per day).



In GNU Emacs 24.5.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.16.7)
 of 2015-11-24 on regnitz
Windowing system distributor `The X.Org Foundation', version 11.0.11702000
System Description:	Ubuntu 15.10

Important settings:
  value of $LC_COLLATE: C
  value of $LANG: en_US.utf8
  value of $XMODIFIERS: 
  locale-coding-system: utf-8-unix

Message #8 received at 22305 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: "Roland Winkler" <winkler <at> gnu.org>
Cc: 22305 <at> debbugs.gnu.org
Subject: Re: bug#22305: 24.5; permanent 100% CPU load for no apparent reason
Date: Mon, 04 Jan 2016 19:16:46 +0200

> Date: Mon, 4 Jan 2016 10:48:02 -0600
> From: "Roland Winkler" <winkler <at> gnu.org>
> 
> Lately emacs gives me some strange problem, where according to `top'
> the CPU load due to the emacs process goes up to a permanent value
> of 100% (and I notice this because the laptop fan starts spinning
> loudly), whereas according to `ps' the emacs process continues to
> give rise to only a marginal CPU load.  While this happens, emacs
> responds normally, so it appears that emacs is not trying to do
> anything unusual in the background.

Not necessarily.  AFAIR, 'top' shows the CPU usage of each program in
terms of processor execution units.  IOW, 100% means Emacs is pegging
a single execution unit.  How many execution units (cores) do you have
on that system?

> What can I do to pin this down further?  So far, I have not noticed
> anything that triggers this behavior reproducibly and my workaround
> has been to restart emacs.  But that's not nice for a recurring
> problem (about once per day).

When this happens, attach a debugger and show us the backtrace,
including the Lisp backtrace.

Message #11 received at 22305 <at> debbugs.gnu.org (full text, mbox):

From: "Roland Winkler" <winkler <at> gnu.org>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 22305 <at> debbugs.gnu.org
Subject: Re: bug#22305: 24.5; permanent 100% CPU load for no apparent reason
Date: Mon, 4 Jan 2016 11:47:44 -0600

On Mon Jan 4 2016 Eli Zaretskii wrote:
> Not necessarily.  AFAIR, 'top' shows the CPU usage of each program
> in terms of processor execution units.  IOW, 100% means Emacs is
> pegging a single execution unit.

Sure.  My point is that normally `top' says that my emacs session
does not take more than 2 or 3% CPU load.  Yet suddenly this goes up
to 100% and the fan starts running loudly, too.

> How many execution units (cores) do you have on that system?

`lshw' says

  Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz

which, I believe, comes with four cores.

> When this happens, attach a debugger and show us the backtrace,
> including the Lisp backtrace.

Thanks, will do that.

Message #14 received at 22305 <at> debbugs.gnu.org (full text, mbox):

From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: Roland Winkler <winkler <at> gnu.org>, 22305 <at> debbugs.gnu.org
Subject: Re: bug#22305: 24.5; permanent 100% CPU load for no apparent reason
Date: Mon, 04 Jan 2016 19:33:08 +0100

Eli Zaretskii <eliz <at> gnu.org> writes:

> When this happens, attach a debugger and show us the backtrace,
> including the Lisp backtrace.

Using profiler.el might also reveal what Emacs is doing.


Michael.

Message #21 received at 22305-done <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: 22305-done <at> debbugs.gnu.org
Subject: Re: bug#22305: 24.5; permanent 100% CPU load for no apparent reason
Date: Wed, 07 Dec 2016 13:57:17 -0500

Since the best part of a year has passed with no further information,
I'm closing this. Please reopen if you can provide the requested
information.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.