Commit 404ff638 authored by Deng-Cheng Zhu's avatar Deng-Cheng Zhu Committed by Ralf Baechle
Browse files

MIPS, Perf-events: Work with the new PMU interface 



This is the MIPS part of the following commits by Peter Zijlstra:

- a4eaf7f1
    perf: Rework the PMU methods

    Replace pmu::{enable,disable,start,stop,unthrottle} with
    pmu::{add,del,start,stop}, all of which take a flags argument.

    The new interface extends the capability to stop a counter while
    keeping it scheduled on the PMU. We replace the throttled state with
    the generic stopped state.

    This also allows us to efficiently stop/start counters over certain
    code paths (like IRQ handlers).

    It also allows scheduling a counter without it starting, allowing for
    a generic frozen state (useful for rotating stopped counters).

    The stopped state is implemented in two different ways, depending on
    how the architecture implemented the throttled state:

     1) We disable the counter:
        a) the pmu has per-counter enable bits, we flip that
        b) we program a NOP event, preserving the counter state

     2) We store the counter state and ignore all read/overflow events

For MIPSXX, the stopped state is implemented in the way of 1.b as above.

- 33696fc0
    perf: Per PMU disable

    Changes perf_disable() into perf_pmu_disable().

- 24cd7f54
    perf: Reduce perf_disable() usage

    Since the current perf_disable() usage is only an optimization,
    remove it for now. This eases the removal of the __weak
    hw_perf_enable() interface.

- b0a873eb
    perf: Register PMU implementations

    Simple registration interface for struct pmu, this provides the
    infrastructure for removing all the weak functions.

- 51b0fe39
    perf: Deconstify struct pmu

    sed -ie 's/const struct pmu\>/struct pmu/g' `git grep -l "const struct pmu\>"`

Reported-by: default avatarWu Zhangjin <wuzhangjin@gmail.com>
Acked-by: default avatarDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: default avatarDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2012/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 91f01737

arch/mips/kernel/perf_event.c

+156 −119
Original line number Diff line number Diff line
@@ -161,41 +161,6 @@ mipspmu_event_set_period(struct perf_event *event, 
	return ret;

}



static int mipspmu_enable(struct perf_event *event)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int idx;

	int err = 0;



	/* To look for a free counter for this event. */

	idx = mipspmu->alloc_counter(cpuc, hwc);

	if (idx < 0) {

		err = idx;

		goto out;

	}



	/*

	 * If there is an event in the counter we are going to use then

	 * make sure it is disabled.

	 */

	event->hw.idx = idx;

	mipspmu->disable_event(idx);

	cpuc->events[idx] = event;



	/* Set the period for the event. */

	mipspmu_event_set_period(event, hwc, idx);



	/* Enable the event. */

	mipspmu->enable_event(hwc, idx);



	/* Propagate our changes to the userspace mapping. */

	perf_event_update_userpage(event);



out:

	return err;

}



static void mipspmu_event_update(struct perf_event *event,

			struct hw_perf_event *hwc,

			int idx)
@@ -231,32 +196,90 @@ again: 
	return;

}



static void mipspmu_disable(struct perf_event *event)

static void mipspmu_start(struct perf_event *event, int flags)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int idx = hwc->idx;



	if (!mipspmu)

		return;



	if (flags & PERF_EF_RELOAD)

		WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));



	WARN_ON(idx < 0 || idx >= mipspmu->num_counters);

	hwc->state = 0;



	/* We are working on a local event. */

	mipspmu->disable_event(idx);

	/* Set the period for the event. */

	mipspmu_event_set_period(event, hwc, hwc->idx);



	/* Enable the event. */

	mipspmu->enable_event(hwc, hwc->idx);

}



static void mipspmu_stop(struct perf_event *event, int flags)

{

	struct hw_perf_event *hwc = &event->hw;



	if (!mipspmu)

		return;



	if (!(hwc->state & PERF_HES_STOPPED)) {

		/* We are working on a local event. */

		mipspmu->disable_event(hwc->idx);

		barrier();

		mipspmu_event_update(event, hwc, hwc->idx);

		hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;

	}

}



	mipspmu_event_update(event, hwc, idx);

	cpuc->events[idx] = NULL;

	clear_bit(idx, cpuc->used_mask);

static int mipspmu_add(struct perf_event *event, int flags)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int idx;

	int err = 0;



	perf_pmu_disable(event->pmu);



	/* To look for a free counter for this event. */

	idx = mipspmu->alloc_counter(cpuc, hwc);

	if (idx < 0) {

		err = idx;

		goto out;

	}



	/*

	 * If there is an event in the counter we are going to use then

	 * make sure it is disabled.

	 */

	event->hw.idx = idx;

	mipspmu->disable_event(idx);

	cpuc->events[idx] = event;



	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;

	if (flags & PERF_EF_START)

		mipspmu_start(event, PERF_EF_RELOAD);



	/* Propagate our changes to the userspace mapping. */

	perf_event_update_userpage(event);



out:

	perf_pmu_enable(event->pmu);

	return err;

}



static void mipspmu_unthrottle(struct perf_event *event)

static void mipspmu_del(struct perf_event *event, int flags)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int idx = hwc->idx;



	mipspmu->enable_event(hwc, hwc->idx);

	WARN_ON(idx < 0 || idx >= mipspmu->num_counters);



	mipspmu_stop(event, PERF_EF_UPDATE);

	cpuc->events[idx] = NULL;

	clear_bit(idx, cpuc->used_mask);



	perf_event_update_userpage(event);

}



static void mipspmu_read(struct perf_event *event)
@@ -270,12 +293,17 @@ static void mipspmu_read(struct perf_event *event) 
	mipspmu_event_update(event, hwc, hwc->idx);

}



static struct pmu pmu = {

	.enable		= mipspmu_enable,

	.disable	= mipspmu_disable,

	.unthrottle	= mipspmu_unthrottle,

	.read		= mipspmu_read,

};

static void mipspmu_enable(struct pmu *pmu)

{

	if (mipspmu)

		mipspmu->start();

}



static void mipspmu_disable(struct pmu *pmu)

{

	if (mipspmu)

		mipspmu->stop();

}



static atomic_t active_events = ATOMIC_INIT(0);

static DEFINE_MUTEX(pmu_reserve_mutex);
@@ -318,6 +346,82 @@ static void mipspmu_free_irq(void) 
		perf_irq = save_perf_irq;

}



/*

 * mipsxx/rm9000/loongson2 have different performance counters, they have

 * specific low-level init routines.

 */

static void reset_counters(void *arg);

static int __hw_perf_event_init(struct perf_event *event);



static void hw_perf_event_destroy(struct perf_event *event)

{

	if (atomic_dec_and_mutex_lock(&active_events,

				&pmu_reserve_mutex)) {

		/*

		 * We must not call the destroy function with interrupts

		 * disabled.

		 */

		on_each_cpu(reset_counters,

			(void *)(long)mipspmu->num_counters, 1);

		mipspmu_free_irq();

		mutex_unlock(&pmu_reserve_mutex);

	}

}



static int mipspmu_event_init(struct perf_event *event)

{

	int err = 0;



	switch (event->attr.type) {

	case PERF_TYPE_RAW:

	case PERF_TYPE_HARDWARE:

	case PERF_TYPE_HW_CACHE:

		break;



	default:

		return -ENOENT;

	}



	if (!mipspmu || event->cpu >= nr_cpumask_bits ||

		(event->cpu >= 0 && !cpu_online(event->cpu)))

		return -ENODEV;



	if (!atomic_inc_not_zero(&active_events)) {

		if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {

			atomic_dec(&active_events);

			return -ENOSPC;

		}



		mutex_lock(&pmu_reserve_mutex);

		if (atomic_read(&active_events) == 0)

			err = mipspmu_get_irq();



		if (!err)

			atomic_inc(&active_events);

		mutex_unlock(&pmu_reserve_mutex);

	}



	if (err)

		return err;



	err = __hw_perf_event_init(event);

	if (err)

		hw_perf_event_destroy(event);



	return err;

}



static struct pmu pmu = {

	.pmu_enable	= mipspmu_enable,

	.pmu_disable	= mipspmu_disable,

	.event_init	= mipspmu_event_init,

	.add		= mipspmu_add,

	.del		= mipspmu_del,

	.start		= mipspmu_start,

	.stop		= mipspmu_stop,

	.read		= mipspmu_read,

};



static inline unsigned int

mipspmu_perf_event_encode(const struct mips_perf_event *pev)

{
@@ -409,73 +513,6 @@ static int validate_group(struct perf_event *event) 
	return 0;

}



/*

 * mipsxx/rm9000/loongson2 have different performance counters, they have

 * specific low-level init routines.

 */

static void reset_counters(void *arg);

static int __hw_perf_event_init(struct perf_event *event);



static void hw_perf_event_destroy(struct perf_event *event)

{

	if (atomic_dec_and_mutex_lock(&active_events,

				&pmu_reserve_mutex)) {

		/*

		 * We must not call the destroy function with interrupts

		 * disabled.

		 */

		on_each_cpu(reset_counters,

			(void *)(long)mipspmu->num_counters, 1);

		mipspmu_free_irq();

		mutex_unlock(&pmu_reserve_mutex);

	}

}



const struct pmu *hw_perf_event_init(struct perf_event *event)

{

	int err = 0;



	if (!mipspmu || event->cpu >= nr_cpumask_bits ||

		(event->cpu >= 0 && !cpu_online(event->cpu)))

		return ERR_PTR(-ENODEV);



	if (!atomic_inc_not_zero(&active_events)) {

		if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {

			atomic_dec(&active_events);

			return ERR_PTR(-ENOSPC);

		}



		mutex_lock(&pmu_reserve_mutex);

		if (atomic_read(&active_events) == 0)

			err = mipspmu_get_irq();



		if (!err)

			atomic_inc(&active_events);

		mutex_unlock(&pmu_reserve_mutex);

	}



	if (err)

		return ERR_PTR(err);



	err = __hw_perf_event_init(event);

	if (err)

		hw_perf_event_destroy(event);



	return err ? ERR_PTR(err) : &pmu;

}



void hw_perf_enable(void)

{

	if (mipspmu)

		mipspmu->start();

}



void hw_perf_disable(void)

{

	if (mipspmu)

		mipspmu->stop();

}



/* This is needed by specific irq handlers in perf_event_*.c */

static void

handle_associated_event(struct cpu_hw_events *cpuc,

arch/mips/kernel/perf_event_mipsxx.c

+2 −0
Original line number Diff line number Diff line
@@ -1045,6 +1045,8 @@ init_hw_perf_events(void) 
			"CPU, irq %d%s\n", mipspmu->name, counters, irq,

			irq < 0 ? " (share with timer interrupt)" : "");



	perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);



	return 0;

}

early_initcall(init_hw_perf_events);

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