Re: [RFC PATCH 0/2] tick/nohz: Add runtime control of non-idle tick suppression

On 10/15/26 8:43 AM, Peng Wang wrote:

Workloads and their need for periodic ticks can change after boot.
This series lets userspace choose at runtime which CPUs in the boot-time
nohz_full set retain the non-idle scheduler tick and which are permitted
to stop it, while preserving the existing isolation configuration.

The first patch adds a per-CPU tick dependency; the second exposes a
sysfs CPU list. Permission defaults to all nohz_full CPUs. Revocation
uses the existing asynchronous kick. Idle tick suppression is unchanged,
and policy persists across hotplug.

So you are basically setting up more nohz_full CPUs than the system actually needs to use at the moment and so want to disable nohz/tick part of nohz_full CPUs that don't need it. Can you elaborate more about the problems solve by introducing this new behavior?

Existing cpuset partition modes do not express this independent tick
policy. Feedback on the proposed interface is welcome.

We are planning to eventually extend cpuset partition mode to change nohz_full at runtime. This is still a work in progress.

Regards,
Longman

Thanks,
Peng

Peng Wang (2):
   tick/nohz: Add a policy dependency for full dynticks
   cpu: Add sysfs control of full dynticks policy

  .../ABI/testing/sysfs-devices-system-cpu      | 40 ++++++++++++
  drivers/base/cpu.c                            | 46 ++++++++++++++
  include/linux/tick.h                          |  8 ++-
  include/trace/events/timer.h                  |  3 +-
  kernel/time/tick-sched.c                      | 62 +++++++++++++++++++
  5 files changed, 156 insertions(+), 3 deletions(-)


base-commit: 0fcb05b72344f40806cbe810de8872f1698bf053