[GIT PULL] isolation: 1Hz residual tick offloading v3

From: Frederic Weisbecker
Date: Wed Jan 03 2018 - 23:26:08 EST


Ingo,

Please pull the sched/0hz branch that can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
sched/0hz

HEAD: 9e932b2cc707209febd130978a5eb9f4a943a3f4

--
Now that scheduler_tick() has become resilient towards the absence of
ticks, current->sched_class->task_tick() is the last piece that needs
at least 1Hz tick to keep scheduler stats alive.

This patchset adds a flag to the isolcpus boot option to offload the
residual 1Hz tick. This way the nohz_full CPUs don't have anymore tick
(assuming nothing else requires it) as their residual 1Hz tick is
offloaded to the housekeepers.

For quick testing, say on CPUs 1-7:

"isolcpus=nohz_offload,domain,1-7"

Thanks,
Frederic
---

Frederic Weisbecker (5):
sched: Rename init_rq_hrtick to hrtick_rq_init
sched/isolation: Add scheduler tick offloading interface
nohz: Allow to check if remote CPU tick is stopped
sched/isolation: Residual 1Hz scheduler tick offload
sched/isolation: Document "nohz_offload" flag


Documentation/admin-guide/kernel-parameters.txt | 7 +-
include/linux/sched/isolation.h | 3 +-
include/linux/tick.h | 2 +
kernel/sched/core.c | 94 +++++++++++++++++++++++--
kernel/sched/isolation.c | 10 +++
kernel/sched/sched.h | 2 +
kernel/time/tick-sched.c | 7 ++
7 files changed, 117 insertions(+), 8 deletions(-)