group.of.nepali.translators team mailing list archive

[Po-Hsu Lin <po-hsu.lin@xxxxxxxxxxxxx>]

** Changed in: linux (Ubuntu)
       Status: Fix Committed => Fix Released

** Changed in: linux (Ubuntu Xenial)
       Status: Fix Committed => Fix Released

-- 
You received this bug notification because you are a member of नेपाली
भाषा समायोजकहरुको समूह, which is subscribed to Xenial.
Matching subscriptions: Ubuntu 16.04 Bugs
https://bugs.launchpad.net/bugs/1645449

Title:
  Linux perf regression in 4.4.0-42 and newer

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Xenial:
  Fix Released

Bug description:
  There is a regression in the 4.4.0-42 kernel update that is still
  present in the latest 4.4.0 update. I have verified that this appears
  in Ubuntu 16.04 and Ubuntu 14.04 (with ubuntu-xenial kernel installed)
  amd64. I also suspect this happens in default Ubuntu 16.10 kernel as
  well, but i have not tested.

  4.4.0-38 did not have this issue.

  in 4.4.0-42 and newer, perf records incorrect timestamps which can be
  verified by running this command:

  $ perf record -a -e sched:sched_-k CLOCK_MONOTONIC switch stress -c 10000 -t 10
  stress: info: [25560] dispatching hogs: 10000 cpu, 0 io, 0 vm, 0 hdd
  stress: info: [25560] successful run completed in 6s
  [ perf record: Woken up 16 times to write data ]
  Warning:
  78487 out of order events recorded.

  
  Note that the warning about out of order events is a symptom of this problem and is not expected to happen. This does not happen(correct behavior) if i run 4.4.0-38 and older, or if i run a fully patched upstream 4.4.35 kernel instead.

  
  This regression has already been fixed upstream but has not been included in ubuntu-xenial  kernel yet. 

  Upstream fix is here:
  https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=78c7b55b362e868e529ab6579134708fcf5539dd

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1645449/+subscriptions