[Bug 1227000] Re: update-notifier is polling every 5 seconds

[Brian Murray]

I was looking at this today and noticed that the things we are actually
monitoring (if somebody is using an UPSTART_SESSION, which I understand
most desktop environments to be doing) are all package related.  Given
that package operations are less frequent than crashes or things we were
monitoring previous to the conversion to upstart session jobs, I'd say
we could increase the poll interval significantly.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to update-notifier in Ubuntu.
https://bugs.launchpad.net/bugs/1227000

Title:
  update-notifier is polling every 5 seconds

Status in The Ubuntu Power Consumption Project:
  New
Status in “update-notifier” package in Ubuntu:
  New

Bug description:
  In order to reduce system wakeups to improve laptop battery life I've
  noticed that update-notifier is polling every 5 seconds, strace'ing
  the process shows:

  recvfrom(6, 0x8b16e4, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)
  poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=3, events=POLLIN}], 3, 4373) = 0 (Timeout)
  recvfrom(6, 0x8b16e4, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)
  poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=3, events=POLLIN}], 3, 4995) = 0 (Timeout)
  recvfrom(6, 0x8b16e4, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)
  poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=3, events=POLLIN}], 3, 4994) = 0 (Timeout)
  recvfrom(6, 0x8b16e4, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)
  poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=3, events=POLLIN}], 3, 4999) = 0 (Timeout)
  recvfrom(6, 0x8b16e4, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)
  poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=3, events=POLLIN}], 3, 4995) = 0 (Timeout)
  recvfrom(6, 0x8b16e4, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)

  It appears that file_monitor_periodic_check() is being called every 5
  seconds and it checks to see if variables such as un->crashreport is
  NULL or un->dpkg_was_run is true.

  From a casual look at the code, these are set by monitor_cb() which is
  called when files are modified, so does this make the 5 second poll
  unnecessary?    Can we remove the 5 second polling and just do the
  file_monitor_periodic_checks when monitor_cb detects something to act
  upon?

  As it stands, polling every 5 seconds unnecessarily keeps the CPU out
  of deep sleep C states and consumes a small amount of power.  This is
  a  low priority issue, but it would be a nice to have fix to make the
  code a little more power optimal.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu-power-consumption/+bug/1227000/+subscriptions