[PATCH 0/2] measure latency of cpu hotplug path

[Prasad Sodagudi]

There are all changes related to cpu hotplug path and would like to seek
upstream review. These are all patches in Qualcomm downstream kernel
for a quite long time. First patch sets the rt prioity to hotplug
task and second patch adds cpuhp trace events.

1) cpu-hotplug: Always use real time scheduling when hotplugging a CPU
2) cpu/hotplug: Add cpuhp_latency trace event

Example logs:-  
cpu online -
         cpuhp/4-200   [004] ....   223.891886: cpuhp_enter: cpu: 0004 target: 213 step: 212 (sched_cpu_activate)
         cpuhp/4-200   [004] ....   223.891894: cpuhp_exit:  cpu: 0004  state: 212 step: 212 ret: 0
              sh-176   [000] ....   223.891912: cpuhp_exit:  cpu: 0004  state: 213 step:  86 ret: 0
              sh-176   [000] ....   223.891915: cpuhp_latency:  cpu:4 state:online latency:3874 USEC ret: 0

cpu offline - 
              sh-176   [000] ....   265.193490: cpuhp_exit:  cpu: 0004  state:   2 step:   2 ret: 0
              sh-176   [000] ....   265.193494: cpuhp_latency:  cpu:4 state:offline latency:57431 USEC ret: 0


Prasad Sodagudi (1):
  cpu/hotplug: Add cpuhp_latency trace event

Syed Rameez Mustafa (1):
  cpu-hotplug: Always use real time scheduling when hotplugging a CPU

 include/trace/events/cpuhp.h | 29 +++++++++++++++++++++++++
 kernel/cpu.c                 | 50 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

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