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Commit 5debecbe authored by Satya Durga Srinivasu Prabhala's avatar Satya Durga Srinivasu Prabhala
Browse files

trace: filter out spurious preemption and IRQs disable traces 



Spurious preemption and IRQs disable traces are observed when
CPUs coming out of LPMs or while switching from idle task to
other task. Add necessary checks to filter out spurious traces.

Change-Id: I82bfde23e7a0837098d96a77c84be9981207571a
Signed-off-by: default avatarSatya Durga Srinivasu Prabhala <satyap@codeaurora.org>
parent eb85c6e5

kernel/sched/core.c

+7 −2
Original line number Original line Diff line number Diff line
@@ -3322,6 +3322,7 @@ struct preempt_store { 
	u64 ts;

	u64 ts;

	unsigned long caddr[4];

	unsigned long caddr[4];

	bool irqs_disabled;

	bool irqs_disabled;

	bool is_idle_task;

};

};





DEFINE_PER_CPU(struct preempt_store, the_ps);

DEFINE_PER_CPU(struct preempt_store, the_ps);
@@ -3331,7 +3332,9 @@ DEFINE_PER_CPU(struct preempt_store, the_ps); 
 */

 */

static inline void preempt_latency_start(int val)

static inline void preempt_latency_start(int val)

{

{

	struct preempt_store *ps = &per_cpu(the_ps, raw_smp_processor_id());

	int cpu = raw_smp_processor_id();

	struct rq *rq = cpu_rq(cpu);

	struct preempt_store *ps = &per_cpu(the_ps, cpu);





	if (preempt_count() == val) {

	if (preempt_count() == val) {

		unsigned long ip = get_lock_parent_ip();

		unsigned long ip = get_lock_parent_ip();
@@ -3344,6 +3347,7 @@ static inline void preempt_latency_start(int val) 
		ps->caddr[2] = CALLER_ADDR2;

		ps->caddr[2] = CALLER_ADDR2;

		ps->caddr[3] = CALLER_ADDR3;

		ps->caddr[3] = CALLER_ADDR3;

		ps->irqs_disabled = irqs_disabled();

		ps->irqs_disabled = irqs_disabled();

		ps->is_idle_task = (rq->curr == rq->idle);





		trace_preempt_off(CALLER_ADDR0, ip);

		trace_preempt_off(CALLER_ADDR0, ip);

	}

	}
@@ -3386,7 +3390,8 @@ static inline void preempt_latency_stop(int val) 
		 * Trace preempt disable stack if preemption

		 * Trace preempt disable stack if preemption

		 * is disabled for more than the threshold.

		 * is disabled for more than the threshold.

		 */

		 */

		if (delta > sysctl_preemptoff_tracing_threshold_ns)

		if (!ps->is_idle_task &&

				delta > sysctl_preemptoff_tracing_threshold_ns)

			trace_sched_preempt_disable(delta, ps->irqs_disabled,

			trace_sched_preempt_disable(delta, ps->irqs_disabled,

						ps->caddr[0], ps->caddr[1],

						ps->caddr[0], ps->caddr[1],

						ps->caddr[2], ps->caddr[3]);

						ps->caddr[2], ps->caddr[3]);

kernel/trace/trace_irqsoff.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/uaccess.h>

#include <linux/uaccess.h>

#include <linux/module.h>

#include <linux/module.h>

#include <linux/ftrace.h>

#include <linux/ftrace.h>

#include <linux/sched.h>

#include <linux/sched/clock.h>

#include <linux/sched/clock.h>

#include <linux/sched/sysctl.h>

#include <linux/sched/sysctl.h>
@@ -636,7 +637,8 @@ void tracer_hardirqs_on(unsigned long a0, unsigned long a1) 
	is = &per_cpu(the_irqsoff, raw_smp_processor_id());

	is = &per_cpu(the_irqsoff, raw_smp_processor_id());

	delta = sched_clock() - is->ts;

	delta = sched_clock() - is->ts;





	if (delta > sysctl_irqsoff_tracing_threshold_ns)

	if (!is_idle_task(current) &&

			delta > sysctl_irqsoff_tracing_threshold_ns)

		trace_irqs_disable(delta, is->caddr[0], is->caddr[1],

		trace_irqs_disable(delta, is->caddr[0], is->caddr[1],

						is->caddr[2], is->caddr[3]);

						is->caddr[2], is->caddr[3]);

	lockdep_on();

	lockdep_on();