This problem occurs with emacs 26.3 but didn't occur with 25.x.
Possibly related to bug#33194.
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")
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.
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.
I double-checked the output of
lsof on one of the running CPU processes
and again couldn't find anything that matched with the Emacs
buffer. However, I did notice that
file-name-history did match some.
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).
"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
"strace -c" emacs when running the CPU/IO job:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
30.79 0.013978 1 15384 poll
21.05 0.009554 1 15799 12395 recvmsg
19.44 0.008827 1 6538 writev
13.96 0.006339 1 12446 rt_sigprocmask
6.97 0.003162 2 1554 pselect6
2.96 0.001342 0 3108 rt_sigreturn
2.95 0.001338 1 1551 read
1.88 0.000855 1 1551 ioctl
0.00 0.000000 0 10 stat
0.00 0.000000 0 1 restart_syscall
0.00 0.000000 0 10 faccessat
------ ----------- ----------- --------- --------- ----------------
100.00 0.045395 57952 12395 total"strace -c emacs when running the CPU/IO job without
global-auto-revert-mode:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
37.41 0.001833 1 1860 1576 recvmsg
27.88 0.001366 1 1619 poll
14.78 0.000724 5 142 pselect6
7.43 0.000364 2 201 writev
6.29 0.000308 1 570 rt_sigprocmask
6.06 0.000297 1 318 24 rt_sigreturn
0.08 0.000004 1 6 write
0.06 0.000003 0 8 read
0.02 0.000001 1 2 openat
0.00 0.000000 0 2 close
0.00 0.000000 0 6 3 recvfrom
0.00 0.000000 0 1 1 faccessat
------ ----------- ----------- --------- --------- ----------------
100.00 0.004900 4735 1604 totalIn GNU Emacs 26.3 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
of 2019-09-16 built on lcy01-amd64-030
Windowing system distributor 'The X.Org Foundation', version 11.0.11906000
System Description: Ubuntu 18.04.3 LTS
Recent messages:
Making completion list...
Saving file /tmp/t10.kythe.json-decoded...
Wrote /tmp/t10.kythe.json-decoded
Quit [5 times]
command-execute: Buffer is read-only: #<buffer *Help*>
Mark set
Quit
Mark saved where search started
Quit [2 times]
Mark saved where search started [2 times]
Quit [4 times]
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