telephony-service-indicator is waking up every 4 seconds adding inotifies on paths that don't exist

[Colin Ian King]

Daily wakeups tests show that telephony-service-indicator is not that idle on an "idle" system:

http://ci.ubuntu.com/power/eventstat/image/3138/machine/6/task/telephony-service-indicator/details/

It is waking up every 4 seconds on a poll() and doing two inotify_add_watch() calls on paths that don't exist, which wastes power on devices such as phones, e.g:

Inotify watches added:
  PID Process Rate/Sec File
  2102 telephony-service-in 0.250 /usr/local/share/applications
  2102 telephony-service-in 0.250 /usr/share/ubuntu-touch/applications

This can be observed with strace:

poll([{fd=7, events=POLLIN}, {fd=8, events=POLLIN}], 2, 3984) = 0 (Timeout)
clock_gettime(CLOCK_MONOTONIC, {10864, 224048956}) = 0
inotify_add_watch(8, "/usr/local/share/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
inotify_add_watch(8, "/usr/share/ubuntu-touch/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
clock_gettime(CLOCK_MONOTONIC, {10864, 229054297}) = 0
poll([{fd=7, events=POLLIN}, {fd=8, events=POLLIN}], 2, 3987) = 0 (Timeout)
clock_gettime(CLOCK_MONOTONIC, {10868, 227833482}) = 0
inotify_add_watch(8, "/usr/local/share/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
inotify_add_watch(8, "/usr/share/ubuntu-touch/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
clock_gettime(CLOCK_MONOTONIC, {10868, 233998598}) = 0

Can these redundant polling checks be reduced or removed? Polling every 4 seconds is a little bit heavy handed IMHO.

[Tiago Salem Herrmann (tiagosh)]

I debugged this issue and the inotify_add_watch() calls start to happen after I call messaging_menu_app_new() in the telephony-service-indicator, so I suppose there is something wrong there in messaging-menu.

[Sebastien Bacher (seb128)]

is that still an issue with the current glib version?
it looks like it could have been the issue resolved recently with
https://git.gnome.org/browse/glib/commit/?id=3b8bc8bacf1fe31cda44fb5293711e87989388ea

[Sebastien Bacher (seb128)]

could you test/comment on whether that's still happening?

[Colin Ian King (colin-king)]

Yep, still polling at the same rate doing inotify add watches:

root@ubuntu-phablet:~# strace -f -p 2078
Process 2078 attached with 4 threads
[pid 2091] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 2081] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 2080] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 2078] restart_syscall(<... resuming interrupted call ...> <unfinished ...>
[pid 2091] <... restart_syscall resumed> ) = 0
[pid 2091] clock_gettime(CLOCK_MONOTONIC, {4118, 702253017}) = 0
[pid 2091] inotify_add_watch(13, "/usr/local/share/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] inotify_add_watch(13, "/usr/share/ubuntu-touch/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] inotify_add_watch(13, "/etc/xdg/xdg-ubuntu-touch", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] clock_gettime(CLOCK_MONOTONIC, {4118, 704436632}) = 0
[pid 2091] poll([{fd=12, events=POLLIN}, {fd=13, events=POLLIN}], 2, 3997) = 0 (Timeout)
[pid 2091] clock_gettime(CLOCK_MONOTONIC, {4122, 706523555}) = 0
[pid 2091] inotify_add_watch(13, "/usr/local/share/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] inotify_add_watch(13, "/usr/share/ubuntu-touch/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] inotify_add_watch(13, "/etc/xdg/xdg-ubuntu-touch", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] clock_gettime(CLOCK_MONOTONIC, {4122, 708504478}) = 0
[pid 2091] poll([{fd=12, events=POLLIN}, {fd=13, events=POLLIN}], 2, 3992) = 0 (Timeout)
[pid 2091] clock_gettime(CLOCK_MONOTONIC, {4126, 705271171}) = 0
[pid 2091] inotify_add_watch(13, "/usr/local/share/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] inotify_add_watch(13, "/usr/share/ubuntu-touch/applications", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] inotify_add_watch(13, "/etc/xdg/xdg-ubuntu-touch", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory)
[pid 2091] clo...

[Iain Lane (laney)]

Which version of libglib2.0-0 were you trying with? It's supposed to be fixed in 2.41.5-1 and if you were trying in ubuntu-rtm this only entered the release on 2014-10-07.

[Tiago Salem Herrmann (tiagosh)]

telephony-service-indicator is still waking up on every 4 seconds, but this time it is caused by NetworkManager emiting signals as far as I can see. (PropertiesChanged, ScanDone, AccessPointAdded and so on)

The indicator does not directly watch for any NetworkManager signals, so I guess this is coming from any of the linked libraries.