GNU bug report logs -
#38644
26.3; emacs uses 100% CPU with auto-revert-mode
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Reported by: Peter Ludemann <peter.ludemann <at> gmail.com>
Date: Tue, 17 Dec 2019 01:25:02 UTC
Severity: normal
Found in version 26.3
Fixed in version 27.1
Done: Michael Albinus <michael.albinus <at> gmx.de>
Bug is archived. No further changes may be made.
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Peter Ludemann <peter.ludemann <at> gmail.com> writes:
Hi Peter,
> This problem occurs with emacs 26.3 but didn't occur with 25.x.
> Possibly related to bug#33194.
That's a good catch.
> My hypothesis is that emacs is monitoring some files that it shouldn't
> but I need some help in figuring out which files are being monitored
> and whether that is indeed a bug.
>
> When I run a CPU-bound job that also does quite a bit of I/O, emacs
> becomes very unresponsive -- running "top", I see CPU usage for emacs
> go into the 50-100% range. (Ubuntu 18.04, emacs 26.3 on a 4-CPU
> machine with SSD disk)
>
> The job I'm running is
> parallel -v --will-cite --keep-order --group -L80 -j8
> (the problem does not go away when I change to "-j3")
You are reading commands from STDIN? Which?
> As far as I know, I don't have any of the output files or directories
> open (I have global-auto-revert-mode set) -- all the outputs go into
> one directory and when I search the Buffer List, I don't see that
> directory.
It might be the default directory of a buffer not bound to a file.
> I upgraded from emacs 25.3 to 26.3 today, with the same .
> emacs.desktop, and the problem wasn't showing with emacs 25.3.
In bug#33194, a patch for Emacs 27.0.50 is mentioned. Do you have a
chance to run this for test?
> Any suggestions on how to track down what's causing the polling? As I
> mentioned, this didn't happen with emacs 25.3 with the same files
> open. It also doesn't happen when I start 26.3 without the
> .emacs.desktop (that is, with nothing in the Buffer List).
Could you show the contents of .emacs.desktop?
What happens if you set auto-revert-use-notify to nil?
What's the value of (pp file-notify-descriptors) ?
What do you see, if you remove the comment of the message call in
file-notify-handle-event (lisp/filenotify.el, line 93)?
> "strace -c" emacs when not running the CPU/IO job:
> % time seconds usecs/call calls errors syscall
> ------ ----------- ----------- --------- --------- ----------------
> 31.63 0.009027 3 2950 2534 recvmsg
> 23.19 0.006618 3 2057 poll
> 13.38 0.003819 3 1100 rt_sigprocmask
> 12.10 0.003454 17 209 pselect6
> 9.17 0.002618 6 466 writev
> 7.62 0.002174 5 405 rt_sigreturn
> 1.21 0.000344 57 6 openat
> 0.37 0.000105 4 30 1 read
> 0.31 0.000089 3 26 timerfd_settime
> 0.28 0.000080 11 7 ioctl
> 0.22 0.000064 64 1 vfork
> 0.11 0.000032 11 3 fcntl
> 0.11 0.000030 4 8 close
> 0.09 0.000026 1 51 9 stat
> 0.06 0.000017 17 1 pipe2
> 0.06 0.000016 0 48 11 faccessat
> 0.04 0.000011 11 1 getuid
> 0.03 0.000009 5 2 wait4
> 0.01 0.000003 1 4 write
> 0.00 0.000000 0 3 fstat
> 0.00 0.000000 0 3 lseek
> 0.00 0.000000 0 1 inotify_add_watch
> 0.00 0.000000 0 1 1 readlinkat
> ------ ----------- ----------- --------- --------- ----------------
> 100.00 0.028536 7383 2556 total
inotify_add_watch is an indication, that file notifications are in
place.
Best regards, Michael.
This bug report was last modified 5 years and 196 days ago.
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