On Tue, Feb 13, 2018 at 02:17:07PM -0800, Sodagudi Prasad wrote: > > This is horrible.. and you seem to have forgotten to explain why you > > care about offline CPUs. > > Up to 4.9 kernel, drivers can register cpu hotplug notfiters and drivers are > able to create perf events dynamically based cpu notifies callback events. > As cpu hot plug is converted to state machine approach from hot plug > notifiers, every driver need to define a cpuhp state and registers with cpu > hotplug state machine for creating perf events dynamically. > > Qualcomm have use cases to monitor the cpu cycles and other hw events > continuously on all cpus from kernel and profiling tools. > So we are thinking that there could be other soc vendors, who are interested > in perf events preserving across cpu hot plug and perf events creation on > hot plugged cores.
But _why_ are you hotplugging to begin with? Just don't do that.
