Redisplay: NS port, high CPU load

[David Reitter <david.reitter@gmail.com>]

I am and users are experiencing regular high CPU load with the NS port, which started some time around late 2015, but according to users co-incided with an OS upgrade, too.  I tried rolling back changes, with limited success: it does seem though that very recently, the problem has become much worse.

Usually, Emacs goes into 100% CPU load, or sometimes high load.  What invariably shows up in my process samples is NSMenu _sidebandUpdate*  (no idea what that does), within ns_upgrade_menubar.  The attachment (sorry, could not export to text) shows an example.

I’m getting the spinning beachball sometimes when entering a minibuffer for a command.

I would like to fix this problem, but have been unsuccessful in tracing it down.  As you can see, we’re spending a lot of time in redisplay.
Is redisplay slow, or is it called again and again?

Advice would be appreciated.  (Yes, this is with Aquamacs, and I can’t tell if the problem exists in GNU Emacs as it probably interacts with some configuration.)



Date/Time:       2016-06-08 15:32:29.059 +1000
Launch Time:     2016-06-08 13:51:42.364 +1000
OS Version:      Mac OS X 10.11.4 (15E65)
Report Version:  7
Analysis Tool:   /usr/bin/sample
----

Call graph:
    2484 Thread_453834: Main Thread   DispatchQueue_<multiple>
    + 2417 start  (in libdyld.dylib) + 1  [0x7fff892d35ad]
    + ! 2417 main  () + 5602  [0x1000c3602]  emacs.c:1606
    + !   2417 Frecursive_edit  () + 218  [0x1000c48ea]  keyboard.c:755
    + !     2417 recursive_edit_1  () + 101  [0x1000c46c5]  keyboard.c:684
    + !       2417 command_loop  () + 158  [0x1000c47ae]  keyboard.c:1078
    + !         2417 internal_catch  () + 54  [0x10013f6b6]  eval.c:1074
    + !           2417 command_loop_2  () + 48  [0x1000d45c0]  keyboard.c:1099
    + !             2417 internal_condition_case  () + 70  [0x10013fb46]  eval.c:1309
    + !               2417 command_loop_1  () + 1154  [0x1000c5552]  keyboard.c:1357
    + !                 2417 read_key_sequence  () + 1959  [0x1000c6e17]  keyboard.c:9101
    + !                   2417 read_char  () + 5783  [0x1000ca407]  keyboard.c:2706
    + !                     2417 sit_for  () + 261  [0x100008515]  dispnew.c:5762
    + !                       1694 wait_reading_process_output  () + 1218  [0x100183482]  process.c:4609
    + !                       : 1694 redisplay_preserve_echo_area  () + 44  [0x100028dfc]  xdisp.c:14286
    + !                       :   970 redisplay_internal  () + 2034  [0x100027282]  xdisp.c:11850
    + !                       :   | 962 update_menu_bar  () + 450  [0x10004c9b2]  xdisp.c:11960
    + !                       :   | + 869 ns_update_menubar  () + 479  [0x1001cba6f]  nsmenu.m:139
    + !                       :   | + ! 868 -[NSApplication setMainMenu:]  (in AppKit) + 1584  [0x7fff8e8dc2c0]
    + !                       :   | + ! : 868 -[NSMenu _addSidebandMenuUpdaterForRoles:token:priority:handler:]  (in AppKit) + 229  [0x7fff8e8dc912]
    + !                       :   | + ! :   868 -[NSMenu _sidebandUpdaterRoles]  (in AppKit) + 41,47,...  [0x7fff8e8dca4d,0x7fff8e8dca53,...]
    + !                       :   | + ! 1 -[NSApplication setMainMenu:]  (in AppKit) + 655  [0x7fff8e8dbf1f]
    + !                       :   | + !   1 objc_msgSend  (in libobjc.A.dylib) + 26  [0x7fff8dbc54da]
    + !                       :   | + 57 ns_update_menubar  () + 1577  [0x1001cbeb9]  nsmenu.m:454