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Commit afb9b0a6 authored by Arun Bharadwaj's avatar Arun Bharadwaj Committed by Ruchi Kandoi
Browse files

tracing/sched: Add trace events to track cpu hotplug. 



Add ftrace event trace_sched_cpu_hotplug to track cpu
hot-add and hot-remove events.

This is useful in a variety of power, performance and
debug analysis scenarios.

Change-Id: I5d202c7a229ffacc3aafb7cf9afee0b0ee7b0931
Signed-off-by: default avatarArun Bharadwaj <abharadw@codeaurora.org>
parent db1dc42c

include/trace/events/sched.h

+25 −0
Original line number Diff line number Diff line
@@ -179,6 +179,31 @@ TRACE_EVENT(sched_migrate_task, 
		  __entry->orig_cpu, __entry->dest_cpu)

);



/*

 * Tracepoint for a CPU going offline/online:

 */

TRACE_EVENT(sched_cpu_hotplug,



	TP_PROTO(int affected_cpu, int error, int status),



	TP_ARGS(affected_cpu, error, status),



	TP_STRUCT__entry(

		__field(	int,	affected_cpu		)

		__field(	int,	error			)

		__field(	int,	status			)

	),



	TP_fast_assign(

		__entry->affected_cpu	= affected_cpu;

		__entry->error		= error;

		__entry->status		= status;

	),



	TP_printk("cpu %d %s error=%d", __entry->affected_cpu,

		__entry->status ? "online" : "offline", __entry->error)

);



DECLARE_EVENT_CLASS(sched_process_template,



	TP_PROTO(struct task_struct *p),

kernel/cpu.c

+4 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ 
#include <linux/lockdep.h>

#include <trace/events/power.h>



#include <trace/events/sched.h>



#include "smpboot.h"



#ifdef CONFIG_SMP
@@ -424,6 +426,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) 


out_release:

	cpu_hotplug_done();

	trace_sched_cpu_hotplug(cpu, err, 0);

	if (!err)

		cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);

	return err;
@@ -499,6 +502,7 @@ out_notify: 
		__cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);

out:

	cpu_hotplug_done();

	trace_sched_cpu_hotplug(cpu, ret, 1);



	return ret;

}