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[Brad Figg <brad.figg@xxxxxxxxxxxxx>]

This bug is missing log files that will aid in diagnosing the problem.
>From a terminal window please run:

apport-collect 1587265

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable
to run this command, please add a comment stating that fact and change
the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the
Ubuntu Kernel Team.

** Changed in: linux (Ubuntu)
       Status: New => Incomplete

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https://bugs.launchpad.net/bugs/1587265

Title:
  ubuntu not work with tickless kernel boot option

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  For redhat, we have such guide like 
  https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/pdf/Performance_Tuning_Guide/Red_Hat_Enterprise_Linux-7-Performance_Tuning_Guide-en-US.pdf

  and for tickless kernel, (use dynamic tickless ways)

  1. config grub with following cmdline

  $ cat /etc/default/grub 
  # If you change this file, run 'update-grub' afterwards to update
  # /boot/grub/grub.cfg.
  # For full documentation of the options in this file, see:
  #   info -f grub -n 'Simple configuration'

  GRUB_DEFAULT=0
  GRUB_HIDDEN_TIMEOUT=0
  GRUB_HIDDEN_TIMEOUT_QUIET=true
  GRUB_TIMEOUT=10
  GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash isolcpus=1-2 nohz_full=1-2"
  GRUB_CMDLINE_LINUX=""


  I used nohz_full here, and it is CPU 1, 2 here.

  2. update-grub after that.
  3. Then reboot system

  4. execute following 
  $ sudo perf stat  -C  1  -e irq_vectors:local_timer_entry taskset -c 1 stress -t 1 -c 1
  stress: info: [3869] dispatching hogs: 1 cpu, 0 io, 0 vm, 0 hdd
  stress: info: [3869] successful run completed in 1s

   Performance counter stats for 'CPU(s) 1':

                 252      irq_vectors:local_timer_entry

         1.001491203 seconds time elapsed

  
  It always 252, (the default 250 HZ), seems tickless kernel option not have any effect, whether config it or not, both have same results.

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