[deliverable/linux.git] / kernel / rcu / rcuperf.c

/*
 * Read-Copy Update module-based performance-test facility
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 * Copyright (C) IBM Corporation, 2015
 *
 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
#include <linux/torture.h>
#include <linux/vmalloc.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");

#define PERF_FLAG "-perf:"
#define PERFOUT_STRING(s) \
	pr_alert("%s" PERF_FLAG s "\n", perf_type)
#define VERBOSE_PERFOUT_STRING(s) \
	do { if (verbose) pr_alert("%s" PERF_FLAG " %s\n", perf_type, s); } while (0)
#define VERBOSE_PERFOUT_ERRSTRING(s) \
	do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0)

torture_param(bool, gp_exp, true, "Use expedited GP wait primitives");
torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
torture_param(int, nreaders, -1, "Number of RCU reader threads");
torture_param(int, nwriters, -1, "Number of RCU updater threads");
torture_param(bool, shutdown, false, "Shutdown at end of performance tests.");
torture_param(bool, verbose, true, "Enable verbose debugging printk()s");

static char *perf_type = "rcu";
module_param(perf_type, charp, 0444);
MODULE_PARM_DESC(perf_type, "Type of RCU to performance-test (rcu, rcu_bh, ...)");

static int nrealreaders;
static int nrealwriters;
static struct task_struct **writer_tasks;
static struct task_struct **reader_tasks;
static struct task_struct *shutdown_task;

static u64 **writer_durations;
static int *writer_n_durations;
static atomic_t n_rcu_perf_reader_started;
static atomic_t n_rcu_perf_writer_started;
static atomic_t n_rcu_perf_writer_finished;
static wait_queue_head_t shutdown_wq;
static u64 t_rcu_perf_writer_started;
static u64 t_rcu_perf_writer_finished;
static unsigned long b_rcu_perf_writer_started;
static unsigned long b_rcu_perf_writer_finished;

static int rcu_perf_writer_state;
#define RTWS_INIT		0
#define RTWS_EXP_SYNC		1
#define RTWS_SYNC		2
#define RTWS_IDLE		2
#define RTWS_STOPPING		3

#define MAX_MEAS 10000
#define MIN_MEAS 100

#if defined(MODULE) || defined(CONFIG_RCU_PERF_TEST_RUNNABLE)
#define RCUPERF_RUNNABLE_INIT 1
#else
#define RCUPERF_RUNNABLE_INIT 0
#endif
static int perf_runnable = RCUPERF_RUNNABLE_INIT;
module_param(perf_runnable, int, 0444);
MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot");

/*
 * Operations vector for selecting different types of tests.
 */

struct rcu_perf_ops {
	int ptype;
	void (*init)(void);
	void (*cleanup)(void);
	int (*readlock)(void);
	void (*readunlock)(int idx);
	unsigned long (*started)(void);
	unsigned long (*completed)(void);
	unsigned long (*exp_completed)(void);
	void (*sync)(void);
	void (*exp_sync)(void);
	const char *name;
};

static struct rcu_perf_ops *cur_ops;

/*
 * Definitions for rcu perf testing.
 */

static int rcu_perf_read_lock(void) __acquires(RCU)
{
	rcu_read_lock();
	return 0;
}

static void rcu_perf_read_unlock(int idx) __releases(RCU)
{
	rcu_read_unlock();
}

static unsigned long __maybe_unused rcu_no_completed(void)
{
	return 0;
}

static void rcu_sync_perf_init(void)
{
}

static struct rcu_perf_ops rcu_ops = {
	.ptype		= RCU_FLAVOR,
	.init		= rcu_sync_perf_init,
	.readlock	= rcu_perf_read_lock,
	.readunlock	= rcu_perf_read_unlock,
	.started	= rcu_batches_started,
	.completed	= rcu_batches_completed,
	.exp_completed	= rcu_exp_batches_completed,
	.sync		= synchronize_rcu,
	.exp_sync	= synchronize_rcu_expedited,
	.name		= "rcu"
};

/*
 * Definitions for rcu_bh perf testing.
 */

static int rcu_bh_perf_read_lock(void) __acquires(RCU_BH)
{
	rcu_read_lock_bh();
	return 0;
}

static void rcu_bh_perf_read_unlock(int idx) __releases(RCU_BH)
{
	rcu_read_unlock_bh();
}

static struct rcu_perf_ops rcu_bh_ops = {
	.ptype		= RCU_BH_FLAVOR,
	.init		= rcu_sync_perf_init,
	.readlock	= rcu_bh_perf_read_lock,
	.readunlock	= rcu_bh_perf_read_unlock,
	.started	= rcu_batches_started_bh,
	.completed	= rcu_batches_completed_bh,
	.exp_completed	= rcu_exp_batches_completed_sched,
	.sync		= synchronize_rcu_bh,
	.exp_sync	= synchronize_rcu_bh_expedited,
	.name		= "rcu_bh"
};

/*
 * Definitions for srcu perf testing.
 */

DEFINE_STATIC_SRCU(srcu_ctl_perf);
static struct srcu_struct *srcu_ctlp = &srcu_ctl_perf;

static int srcu_perf_read_lock(void) __acquires(srcu_ctlp)
{
	return srcu_read_lock(srcu_ctlp);
}

static void srcu_perf_read_unlock(int idx) __releases(srcu_ctlp)
{
	srcu_read_unlock(srcu_ctlp, idx);
}

static unsigned long srcu_perf_completed(void)
{
	return srcu_batches_completed(srcu_ctlp);
}

static void srcu_perf_synchronize(void)
{
	synchronize_srcu(srcu_ctlp);
}

static void srcu_perf_synchronize_expedited(void)
{
	synchronize_srcu_expedited(srcu_ctlp);
}

static struct rcu_perf_ops srcu_ops = {
	.ptype		= SRCU_FLAVOR,
	.init		= rcu_sync_perf_init,
	.readlock	= srcu_perf_read_lock,
	.readunlock	= srcu_perf_read_unlock,
	.started	= NULL,
	.completed	= srcu_perf_completed,
	.exp_completed	= srcu_perf_completed,
	.sync		= srcu_perf_synchronize,
	.exp_sync	= srcu_perf_synchronize_expedited,
	.name		= "srcu"
};

/*
 * Definitions for sched perf testing.
 */

static int sched_perf_read_lock(void)
{
	preempt_disable();
	return 0;
}

static void sched_perf_read_unlock(int idx)
{
	preempt_enable();
}

static struct rcu_perf_ops sched_ops = {
	.ptype		= RCU_SCHED_FLAVOR,
	.init		= rcu_sync_perf_init,
	.readlock	= sched_perf_read_lock,
	.readunlock	= sched_perf_read_unlock,
	.started	= rcu_batches_started_sched,
	.completed	= rcu_batches_completed_sched,
	.exp_completed	= rcu_exp_batches_completed_sched,
	.sync		= synchronize_sched,
	.exp_sync	= synchronize_sched_expedited,
	.name		= "sched"
};

#ifdef CONFIG_TASKS_RCU

/*
 * Definitions for RCU-tasks perf testing.
 */

static int tasks_perf_read_lock(void)
{
	return 0;
}

static void tasks_perf_read_unlock(int idx)
{
}

static struct rcu_perf_ops tasks_ops = {
	.ptype		= RCU_TASKS_FLAVOR,
	.init		= rcu_sync_perf_init,
	.readlock	= tasks_perf_read_lock,
	.readunlock	= tasks_perf_read_unlock,
	.started	= rcu_no_completed,
	.completed	= rcu_no_completed,
	.sync		= synchronize_rcu_tasks,
	.exp_sync	= synchronize_rcu_tasks,
	.name		= "tasks"
};

#define RCUPERF_TASKS_OPS &tasks_ops,

static bool __maybe_unused torturing_tasks(void)
{
	return cur_ops == &tasks_ops;
}

#else /* #ifdef CONFIG_TASKS_RCU */

#define RCUPERF_TASKS_OPS

static bool __maybe_unused torturing_tasks(void)
{
	return false;
}

#endif /* #else #ifdef CONFIG_TASKS_RCU */

/*
 * If performance tests complete, wait for shutdown to commence.
 */
static void rcu_perf_wait_shutdown(void)
{
	cond_resched_rcu_qs();
	if (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters)
		return;
	while (!torture_must_stop())
		schedule_timeout_uninterruptible(1);
}

/*
 * RCU perf reader kthread.  Repeatedly does empty RCU read-side
 * critical section, minimizing update-side interference.
 */
static int
rcu_perf_reader(void *arg)
{
	unsigned long flags;
	int idx;
	long me = (long)arg;

	VERBOSE_PERFOUT_STRING("rcu_perf_reader task started");
	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
	set_user_nice(current, MAX_NICE);
	atomic_inc(&n_rcu_perf_reader_started);

	do {
		local_irq_save(flags);
		idx = cur_ops->readlock();
		cur_ops->readunlock(idx);
		local_irq_restore(flags);
		rcu_perf_wait_shutdown();
	} while (!torture_must_stop());
	torture_kthread_stopping("rcu_perf_reader");
	return 0;
}

/*
 * RCU perf writer kthread.  Repeatedly does a grace period.
 */
static int
rcu_perf_writer(void *arg)
{
	int i = 0;
	int i_max;
	long me = (long)arg;
	struct sched_param sp;
	bool started = false, done = false, alldone = false;
	u64 t;
	u64 *wdp;
	u64 *wdpp = writer_durations[me];

	VERBOSE_PERFOUT_STRING("rcu_perf_writer task started");
	WARN_ON(rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp);
	WARN_ON(rcu_gp_is_normal() && gp_exp);
	WARN_ON(!wdpp);
	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
	sp.sched_priority = 1;
	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);

	if (holdoff)
		schedule_timeout_uninterruptible(holdoff * HZ);

	t = ktime_get_mono_fast_ns();
	if (atomic_inc_return(&n_rcu_perf_writer_started) >= nrealwriters) {
		t_rcu_perf_writer_started = t;
		if (gp_exp) {
			b_rcu_perf_writer_started =
				cur_ops->exp_completed() / 2;
		} else {
			b_rcu_perf_writer_started =
				cur_ops->completed();
		}
	}

	do {
		wdp = &wdpp[i];
		*wdp = ktime_get_mono_fast_ns();
		if (gp_exp) {
			rcu_perf_writer_state = RTWS_EXP_SYNC;
			cur_ops->exp_sync();
		} else {
			rcu_perf_writer_state = RTWS_SYNC;
			cur_ops->sync();
		}
		rcu_perf_writer_state = RTWS_IDLE;
		t = ktime_get_mono_fast_ns();
		*wdp = t - *wdp;
		i_max = i;
		if (!started &&
		    atomic_read(&n_rcu_perf_writer_started) >= nrealwriters)
			started = true;
		if (!done && i >= MIN_MEAS) {
			done = true;
			sp.sched_priority = 0;
			sched_setscheduler_nocheck(current,
						   SCHED_NORMAL, &sp);
			pr_alert("%s" PERF_FLAG
				 "rcu_perf_writer %ld has %d measurements\n",
				 perf_type, me, MIN_MEAS);
			if (atomic_inc_return(&n_rcu_perf_writer_finished) >=
			    nrealwriters) {
				schedule_timeout_interruptible(10);
				rcu_ftrace_dump(DUMP_ALL);
				PERFOUT_STRING("Test complete");
				t_rcu_perf_writer_finished = t;
				if (gp_exp) {
					b_rcu_perf_writer_finished =
						cur_ops->exp_completed() / 2;
				} else {
					b_rcu_perf_writer_finished =
						cur_ops->completed();
				}
				if (shutdown) {
					smp_mb(); /* Assign before wake. */
					wake_up(&shutdown_wq);
				}
			}
		}
		if (done && !alldone &&
		    atomic_read(&n_rcu_perf_writer_finished) >= nrealwriters)
			alldone = true;
		if (started && !alldone && i < MAX_MEAS - 1)
			i++;
		rcu_perf_wait_shutdown();
	} while (!torture_must_stop());
	rcu_perf_writer_state = RTWS_STOPPING;
	writer_n_durations[me] = i_max;
	torture_kthread_stopping("rcu_perf_writer");
	return 0;
}

static inline void
rcu_perf_print_module_parms(struct rcu_perf_ops *cur_ops, const char *tag)
{
	pr_alert("%s" PERF_FLAG
		 "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n",
		 perf_type, tag, nrealreaders, nrealwriters, verbose, shutdown);
}

static void
rcu_perf_cleanup(void)
{
	int i;
	int j;
	int ngps = 0;
	u64 *wdp;
	u64 *wdpp;

	if (torture_cleanup_begin())
		return;

	if (reader_tasks) {
		for (i = 0; i < nrealreaders; i++)
			torture_stop_kthread(rcu_perf_reader,
					     reader_tasks[i]);
		kfree(reader_tasks);
	}

	if (writer_tasks) {
		for (i = 0; i < nrealwriters; i++) {
			torture_stop_kthread(rcu_perf_writer,
					     writer_tasks[i]);
			if (!writer_n_durations)
				continue;
			j = writer_n_durations[i];
			pr_alert("%s%s writer %d gps: %d\n",
				 perf_type, PERF_FLAG, i, j);
			ngps += j;
		}
		pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
			 perf_type, PERF_FLAG,
			 t_rcu_perf_writer_started, t_rcu_perf_writer_finished,
			 t_rcu_perf_writer_finished -
			 t_rcu_perf_writer_started,
			 ngps,
			 b_rcu_perf_writer_finished -
			 b_rcu_perf_writer_started);
		for (i = 0; i < nrealwriters; i++) {
			if (!writer_durations)
				break;
			if (!writer_n_durations)
				continue;
			wdpp = writer_durations[i];
			if (!wdpp)
				continue;
			for (j = 0; j <= writer_n_durations[i]; j++) {
				wdp = &wdpp[j];
				pr_alert("%s%s %4d writer-duration: %5d %llu\n",
					perf_type, PERF_FLAG,
					i, j, *wdp);
				if (j % 100 == 0)
					schedule_timeout_uninterruptible(1);
			}
			kfree(writer_durations[i]);
		}
		kfree(writer_tasks);
		kfree(writer_durations);
		kfree(writer_n_durations);
	}

	/* Do flavor-specific cleanup operations.  */
	if (cur_ops->cleanup != NULL)
		cur_ops->cleanup();

	torture_cleanup_end();
}

/*
 * Return the number if non-negative.  If -1, the number of CPUs.
 * If less than -1, that much less than the number of CPUs, but
 * at least one.
 */
static int compute_real(int n)
{
	int nr;

	if (n >= 0) {
		nr = n;
	} else {
		nr = num_online_cpus() + 1 + n;
		if (nr <= 0)
			nr = 1;
	}
	return nr;
}

/*
 * RCU perf shutdown kthread.  Just waits to be awakened, then shuts
 * down system.
 */
static int
rcu_perf_shutdown(void *arg)
{
	do {
		wait_event(shutdown_wq,
			   atomic_read(&n_rcu_perf_writer_finished) >=
			   nrealwriters);
	} while (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters);
	smp_mb(); /* Wake before output. */
	rcu_perf_cleanup();
	kernel_power_off();
	return -EINVAL;
}

static int __init
rcu_perf_init(void)
{
	long i;
	int firsterr = 0;
	static struct rcu_perf_ops *perf_ops[] = {
		&rcu_ops, &rcu_bh_ops, &srcu_ops, &sched_ops,
		RCUPERF_TASKS_OPS
	};

	if (!torture_init_begin(perf_type, verbose, &perf_runnable))
		return -EBUSY;

	/* Process args and tell the world that the perf'er is on the job. */
	for (i = 0; i < ARRAY_SIZE(perf_ops); i++) {
		cur_ops = perf_ops[i];
		if (strcmp(perf_type, cur_ops->name) == 0)
			break;
	}
	if (i == ARRAY_SIZE(perf_ops)) {
		pr_alert("rcu-perf: invalid perf type: \"%s\"\n",
			 perf_type);
		pr_alert("rcu-perf types:");
		for (i = 0; i < ARRAY_SIZE(perf_ops); i++)
			pr_alert(" %s", perf_ops[i]->name);
		pr_alert("\n");
		firsterr = -EINVAL;
		goto unwind;
	}
	if (cur_ops->init)
		cur_ops->init();

	nrealwriters = compute_real(nwriters);
	nrealreaders = compute_real(nreaders);
	atomic_set(&n_rcu_perf_reader_started, 0);
	atomic_set(&n_rcu_perf_writer_started, 0);
	atomic_set(&n_rcu_perf_writer_finished, 0);
	rcu_perf_print_module_parms(cur_ops, "Start of test");

	/* Start up the kthreads. */

	if (shutdown) {
		init_waitqueue_head(&shutdown_wq);
		firsterr = torture_create_kthread(rcu_perf_shutdown, NULL,
						  shutdown_task);
		if (firsterr)
			goto unwind;
		schedule_timeout_uninterruptible(1);
	}
	reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
			       GFP_KERNEL);
	if (reader_tasks == NULL) {
		VERBOSE_PERFOUT_ERRSTRING("out of memory");
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealreaders; i++) {
		firsterr = torture_create_kthread(rcu_perf_reader, (void *)i,
						  reader_tasks[i]);
		if (firsterr)
			goto unwind;
	}
	while (atomic_read(&n_rcu_perf_reader_started) < nrealreaders)
		schedule_timeout_uninterruptible(1);
	writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
			       GFP_KERNEL);
	writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
				   GFP_KERNEL);
	writer_n_durations =
		kcalloc(nrealwriters, sizeof(*writer_n_durations),
			GFP_KERNEL);
	if (!writer_tasks || !writer_durations || !writer_n_durations) {
		VERBOSE_PERFOUT_ERRSTRING("out of memory");
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealwriters; i++) {
		writer_durations[i] =
			kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
				GFP_KERNEL);
		if (!writer_durations[i])
			goto unwind;
		firsterr = torture_create_kthread(rcu_perf_writer, (void *)i,
						  writer_tasks[i]);
		if (firsterr)
			goto unwind;
	}
	torture_init_end();
	return 0;

unwind:
	torture_init_end();
	rcu_perf_cleanup();
	return firsterr;
}

module_init(rcu_perf_init);
module_exit(rcu_perf_cleanup);
Commit	Line	Data
8704baab PM	1	/*
	2	* Read-Copy Update module-based performance-test facility
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, you can access it online at
	16	* http://www.gnu.org/licenses/gpl-2.0.html.
	17	*
	18	* Copyright (C) IBM Corporation, 2015
	19	*
	20	* Authors: Paul E. McKenney <paulmck@us.ibm.com>
	21	*/
	22	#include <linux/types.h>
	23	#include <linux/kernel.h>
	24	#include <linux/init.h>
	25	#include <linux/module.h>
	26	#include <linux/kthread.h>
	27	#include <linux/err.h>
	28	#include <linux/spinlock.h>
	29	#include <linux/smp.h>
	30	#include <linux/rcupdate.h>
	31	#include <linux/interrupt.h>
	32	#include <linux/sched.h>
	33	#include <linux/atomic.h>
	34	#include <linux/bitops.h>
	35	#include <linux/completion.h>
	36	#include <linux/moduleparam.h>
	37	#include <linux/percpu.h>
	38	#include <linux/notifier.h>
	39	#include <linux/reboot.h>
	40	#include <linux/freezer.h>
	41	#include <linux/cpu.h>
	42	#include <linux/delay.h>
	43	#include <linux/stat.h>
	44	#include <linux/srcu.h>
	45	#include <linux/slab.h>
	46	#include <asm/byteorder.h>
	47	#include <linux/torture.h>
	48	#include <linux/vmalloc.h>
	49
	50	MODULE_LICENSE("GPL");
	51	MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");
	52
	53	#define PERF_FLAG "-perf:"
	54	#define PERFOUT_STRING(s) \
	55	pr_alert("%s" PERF_FLAG s "\n", perf_type)
	56	#define VERBOSE_PERFOUT_STRING(s) \
	57	do { if (verbose) pr_alert("%s" PERF_FLAG " %s\n", perf_type, s); } while (0)
	58	#define VERBOSE_PERFOUT_ERRSTRING(s) \
	59	do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0)
	60
	61	torture_param(bool, gp_exp, true, "Use expedited GP wait primitives");
df37e66b	62	torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
8704baab PM	63	torture_param(int, nreaders, -1, "Number of RCU reader threads");
	64	torture_param(int, nwriters, -1, "Number of RCU updater threads");
	65	torture_param(bool, shutdown, false, "Shutdown at end of performance tests.");
	66	torture_param(bool, verbose, true, "Enable verbose debugging printk()s");
	67
	68	static char *perf_type = "rcu";
	69	module_param(perf_type, charp, 0444);
	70	MODULE_PARM_DESC(perf_type, "Type of RCU to performance-test (rcu, rcu_bh, ...)");
	71
	72	static int nrealreaders;
	73	static int nrealwriters;
	74	static struct task_struct **writer_tasks;
	75	static struct task_struct **reader_tasks;
	76	static struct task_struct *shutdown_task;
	77
	78	static u64 **writer_durations;
	79	static int *writer_n_durations;
	80	static atomic_t n_rcu_perf_reader_started;
	81	static atomic_t n_rcu_perf_writer_started;
	82	static atomic_t n_rcu_perf_writer_finished;
	83	static wait_queue_head_t shutdown_wq;
	84	static u64 t_rcu_perf_writer_started;
	85	static u64 t_rcu_perf_writer_finished;
	86	static unsigned long b_rcu_perf_writer_started;
	87	static unsigned long b_rcu_perf_writer_finished;
	88
	89	static int rcu_perf_writer_state;
	90	#define RTWS_INIT 0
	91	#define RTWS_EXP_SYNC 1
	92	#define RTWS_SYNC 2
	93	#define RTWS_IDLE 2
	94	#define RTWS_STOPPING 3
	95
	96	#define MAX_MEAS 10000
	97	#define MIN_MEAS 100
	98
	99	#if defined(MODULE) \|\| defined(CONFIG_RCU_PERF_TEST_RUNNABLE)
	100	#define RCUPERF_RUNNABLE_INIT 1
	101	#else
	102	#define RCUPERF_RUNNABLE_INIT 0
	103	#endif
	104	static int perf_runnable = RCUPERF_RUNNABLE_INIT;
	105	module_param(perf_runnable, int, 0444);
	106	MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot");
	107
	108	/*
	109	* Operations vector for selecting different types of tests.
	110	*/
	111
	112	struct rcu_perf_ops {
	113	int ptype;
	114	void (*init)(void);
	115	void (*cleanup)(void);
	116	int (*readlock)(void);
	117	void (*readunlock)(int idx);
	118	unsigned long (*started)(void);
	119	unsigned long (*completed)(void);
	120	unsigned long (*exp_completed)(void);
	121	void (*sync)(void);
	122	void (*exp_sync)(void);
	123	const char *name;
	124	};
	125
	126	static struct rcu_perf_ops *cur_ops;
127
128	/*
129	* Definitions for rcu perf testing.
130	*/
131
132	static int rcu_perf_read_lock(void) __acquires(RCU)
133	{
134	rcu_read_lock();
135	return 0;
136	}
137
138	static void rcu_perf_read_unlock(int idx) __releases(RCU)
139	{
140	rcu_read_unlock();
141	}
142
143	static unsigned long __maybe_unused rcu_no_completed(void)
144	{
145	return 0;
146	}
147
148	static void rcu_sync_perf_init(void)
149	{
150	}
151
152	static struct rcu_perf_ops rcu_ops = {
153	.ptype = RCU_FLAVOR,
154	.init = rcu_sync_perf_init,
155	.readlock = rcu_perf_read_lock,
156	.readunlock = rcu_perf_read_unlock,
157	.started = rcu_batches_started,
158	.completed = rcu_batches_completed,
159	.exp_completed = rcu_exp_batches_completed,
160	.sync = synchronize_rcu,
161	.exp_sync = synchronize_rcu_expedited,
162	.name = "rcu"
163	};
164
165	/*
166	* Definitions for rcu_bh perf testing.
167	*/
168
169	static int rcu_bh_perf_read_lock(void) __acquires(RCU_BH)
170	{
171	rcu_read_lock_bh();
172	return 0;
173	}
174
175	static void rcu_bh_perf_read_unlock(int idx) __releases(RCU_BH)
176	{
177	rcu_read_unlock_bh();
178	}
179
180	static struct rcu_perf_ops rcu_bh_ops = {
181	.ptype = RCU_BH_FLAVOR,
182	.init = rcu_sync_perf_init,
183	.readlock = rcu_bh_perf_read_lock,
184	.readunlock = rcu_bh_perf_read_unlock,
185	.started = rcu_batches_started_bh,
186	.completed = rcu_batches_completed_bh,
187	.exp_completed = rcu_exp_batches_completed_sched,
188	.sync = synchronize_rcu_bh,
189	.exp_sync = synchronize_rcu_bh_expedited,
190	.name = "rcu_bh"
191	};
192
193	/*
194	* Definitions for srcu perf testing.
195	*/
196
197	DEFINE_STATIC_SRCU(srcu_ctl_perf);
198	static struct srcu_struct *srcu_ctlp = &srcu_ctl_perf;
199
200	static int srcu_perf_read_lock(void) __acquires(srcu_ctlp)
201	{
202	return srcu_read_lock(srcu_ctlp);
203	}
204
205	static void srcu_perf_read_unlock(int idx) __releases(srcu_ctlp)
206	{
207	srcu_read_unlock(srcu_ctlp, idx);
208	}
209
210	static unsigned long srcu_perf_completed(void)
211	{
212	return srcu_batches_completed(srcu_ctlp);
213	}
214
215	static void srcu_perf_synchronize(void)
216	{
217	synchronize_srcu(srcu_ctlp);
218	}
219
220	static void srcu_perf_synchronize_expedited(void)
221	{
222	synchronize_srcu_expedited(srcu_ctlp);
223	}
224
225	static struct rcu_perf_ops srcu_ops = {
226	.ptype = SRCU_FLAVOR,
227	.init = rcu_sync_perf_init,
228	.readlock = srcu_perf_read_lock,
229	.readunlock = srcu_perf_read_unlock,
230	.started = NULL,
231	.completed = srcu_perf_completed,
232	.exp_completed = srcu_perf_completed,
233	.sync = srcu_perf_synchronize,
234	.exp_sync = srcu_perf_synchronize_expedited,
235	.name = "srcu"
236	};
237
238	/*
239	* Definitions for sched perf testing.
240	*/
241
242	static int sched_perf_read_lock(void)
243	{
244	preempt_disable();
245	return 0;
246	}
247
248	static void sched_perf_read_unlock(int idx)
249	{
250	preempt_enable();
251	}
252
253	static struct rcu_perf_ops sched_ops = {
254	.ptype = RCU_SCHED_FLAVOR,
255	.init = rcu_sync_perf_init,
256	.readlock = sched_perf_read_lock,
257	.readunlock = sched_perf_read_unlock,
258	.started = rcu_batches_started_sched,
259	.completed = rcu_batches_completed_sched,
260	.exp_completed = rcu_exp_batches_completed_sched,
261	.sync = synchronize_sched,
262	.exp_sync = synchronize_sched_expedited,
263	.name = "sched"
264	};
265
266	#ifdef CONFIG_TASKS_RCU
267
268	/*
269	* Definitions for RCU-tasks perf testing.
270	*/
271
272	static int tasks_perf_read_lock(void)
273	{
274	return 0;
275	}
276
277	static void tasks_perf_read_unlock(int idx)
278	{
279	}
280
281	static struct rcu_perf_ops tasks_ops = {
282	.ptype = RCU_TASKS_FLAVOR,
283	.init = rcu_sync_perf_init,
284	.readlock = tasks_perf_read_lock,
285	.readunlock = tasks_perf_read_unlock,
286	.started = rcu_no_completed,
287	.completed = rcu_no_completed,
288	.sync = synchronize_rcu_tasks,
289	.exp_sync = synchronize_rcu_tasks,
290	.name = "tasks"
291	};
292
293	#define RCUPERF_TASKS_OPS &tasks_ops,
294
295	static bool __maybe_unused torturing_tasks(void)
296	{
297	return cur_ops == &tasks_ops;
298	}
299
300	#else /* #ifdef CONFIG_TASKS_RCU */
301
302	#define RCUPERF_TASKS_OPS
303
304	static bool __maybe_unused torturing_tasks(void)
305	{
306	return false;
307	}
308
309	#endif /* #else #ifdef CONFIG_TASKS_RCU */
310
311	/*
312	* If performance tests complete, wait for shutdown to commence.
313	*/
314	static void rcu_perf_wait_shutdown(void)
315	{
316	cond_resched_rcu_qs();
317	if (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters)
318	return;
319	while (!torture_must_stop())
320	schedule_timeout_uninterruptible(1);
321	}
322
323	/*
324	* RCU perf reader kthread. Repeatedly does empty RCU read-side
325	* critical section, minimizing update-side interference.
326	*/
327	static int
328	rcu_perf_reader(void *arg)
329	{
330	unsigned long flags;
331	int idx;
6b558c4c	332	long me = (long)arg;
8704baab PM	333
8704baab PM	334	VERBOSE_PERFOUT_STRING("rcu_perf_reader task started");
6b558c4c	335	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
8704baab PM	336	set_user_nice(current, MAX_NICE);
	337	atomic_inc(&n_rcu_perf_reader_started);
	338
	339	do {
	340	local_irq_save(flags);
	341	idx = cur_ops->readlock();
	342	cur_ops->readunlock(idx);
	343	local_irq_restore(flags);
	344	rcu_perf_wait_shutdown();
	345	} while (!torture_must_stop());
	346	torture_kthread_stopping("rcu_perf_reader");
	347	return 0;
	348	}
	349
	350	/*
	351	* RCU perf writer kthread. Repeatedly does a grace period.
	352	*/
	353	static int
	354	rcu_perf_writer(void *arg)
	355	{
	356	int i = 0;
	357	int i_max;
	358	long me = (long)arg;
2094c995	359	struct sched_param sp;
8704baab PM	360	bool started = false, done = false, alldone = false;
	361	u64 t;
	362	u64 *wdp;
	363	u64 *wdpp = writer_durations[me];
	364
	365	VERBOSE_PERFOUT_STRING("rcu_perf_writer task started");
	366	WARN_ON(rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp);
	367	WARN_ON(rcu_gp_is_normal() && gp_exp);
	368	WARN_ON(!wdpp);
6b558c4c	369	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
2094c995 PM	370	sp.sched_priority = 1;
2094c995 PM	371	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
df37e66b PM	372
	373	if (holdoff)
	374	schedule_timeout_uninterruptible(holdoff * HZ);
	375
8704baab PM	376	t = ktime_get_mono_fast_ns();
	377	if (atomic_inc_return(&n_rcu_perf_writer_started) >= nrealwriters) {
	378	t_rcu_perf_writer_started = t;
	379	if (gp_exp) {
	380	b_rcu_perf_writer_started =
	381	cur_ops->exp_completed() / 2;
	382	} else {
	383	b_rcu_perf_writer_started =
	384	cur_ops->completed();
	385	}
	386	}
	387
	388	do {
	389	wdp = &wdpp[i];
	390	*wdp = ktime_get_mono_fast_ns();
	391	if (gp_exp) {
	392	rcu_perf_writer_state = RTWS_EXP_SYNC;
	393	cur_ops->exp_sync();
	394	} else {
	395	rcu_perf_writer_state = RTWS_SYNC;
	396	cur_ops->sync();
	397	}
	398	rcu_perf_writer_state = RTWS_IDLE;
	399	t = ktime_get_mono_fast_ns();
	400	wdp = t - wdp;
	401	i_max = i;
	402	if (!started &&
	403	atomic_read(&n_rcu_perf_writer_started) >= nrealwriters)
	404	started = true;
	405	if (!done && i >= MIN_MEAS) {
	406	done = true;
620316e5 PM	407	sp.sched_priority = 0;
	408	sched_setscheduler_nocheck(current,
	409	SCHED_NORMAL, &sp);
8704baab PM	410	pr_alert("%s" PERF_FLAG
	411	"rcu_perf_writer %ld has %d measurements\n",
	412	perf_type, me, MIN_MEAS);
	413	if (atomic_inc_return(&n_rcu_perf_writer_finished) >=
	414	nrealwriters) {
620316e5	415	schedule_timeout_interruptible(10);
ac2bb275	416	rcu_ftrace_dump(DUMP_ALL);
8704baab PM	417	PERFOUT_STRING("Test complete");
	418	t_rcu_perf_writer_finished = t;
	419	if (gp_exp) {
	420	b_rcu_perf_writer_finished =
	421	cur_ops->exp_completed() / 2;
	422	} else {
	423	b_rcu_perf_writer_finished =
	424	cur_ops->completed();
	425	}
e6fb1fc1 AS	426	if (shutdown) {
	427	smp_mb(); /* Assign before wake. */
	428	wake_up(&shutdown_wq);
	429	}
8704baab PM	430	}
	431	}
	432	if (done && !alldone &&
	433	atomic_read(&n_rcu_perf_writer_finished) >= nrealwriters)
	434	alldone = true;
	435	if (started && !alldone && i < MAX_MEAS - 1)
	436	i++;
	437	rcu_perf_wait_shutdown();
	438	} while (!torture_must_stop());
	439	rcu_perf_writer_state = RTWS_STOPPING;
	440	writer_n_durations[me] = i_max;
	441	torture_kthread_stopping("rcu_perf_writer");
	442	return 0;
	443	}
	444
	445	static inline void
	446	rcu_perf_print_module_parms(struct rcu_perf_ops cur_ops, const char tag)
	447	{
	448	pr_alert("%s" PERF_FLAG
	449	"--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n",
	450	perf_type, tag, nrealreaders, nrealwriters, verbose, shutdown);
	451	}
	452
	453	static void
	454	rcu_perf_cleanup(void)
	455	{
	456	int i;
	457	int j;
	458	int ngps = 0;
	459	u64 *wdp;
	460	u64 *wdpp;
	461
	462	if (torture_cleanup_begin())
	463	return;
	464
	465	if (reader_tasks) {
	466	for (i = 0; i < nrealreaders; i++)
	467	torture_stop_kthread(rcu_perf_reader,
	468	reader_tasks[i]);
	469	kfree(reader_tasks);
	470	}
	471
	472	if (writer_tasks) {
	473	for (i = 0; i < nrealwriters; i++) {
	474	torture_stop_kthread(rcu_perf_writer,
	475	writer_tasks[i]);
	476	if (!writer_n_durations)
	477	continue;
	478	j = writer_n_durations[i];
	479	pr_alert("%s%s writer %d gps: %d\n",
	480	perf_type, PERF_FLAG, i, j);
	481	ngps += j;
	482	}
	483	pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
	484	perf_type, PERF_FLAG,
	485	t_rcu_perf_writer_started, t_rcu_perf_writer_finished,
	486	t_rcu_perf_writer_finished -
	487	t_rcu_perf_writer_started,
	488	ngps,
	489	b_rcu_perf_writer_finished -
	490	b_rcu_perf_writer_started);
	491	for (i = 0; i < nrealwriters; i++) {
	492	if (!writer_durations)
	493	break;
494	if (!writer_n_durations)
495	continue;
496	wdpp = writer_durations[i];
497	if (!wdpp)
498	continue;
499	for (j = 0; j <= writer_n_durations[i]; j++) {
500	wdp = &wdpp[j];
501	pr_alert("%s%s %4d writer-duration: %5d %llu\n",
502	perf_type, PERF_FLAG,
503	i, j, *wdp);
504	if (j % 100 == 0)
505	schedule_timeout_uninterruptible(1);
506	}
507	kfree(writer_durations[i]);
508	}
509	kfree(writer_tasks);
510	kfree(writer_durations);
511	kfree(writer_n_durations);
512	}
513
514	/* Do flavor-specific cleanup operations. */
515	if (cur_ops->cleanup != NULL)
516	cur_ops->cleanup();
517
518	torture_cleanup_end();
519	}
520
521	/*
522	* Return the number if non-negative. If -1, the number of CPUs.
523	* If less than -1, that much less than the number of CPUs, but
524	* at least one.
525	*/
526	static int compute_real(int n)
527	{
528	int nr;
529
530	if (n >= 0) {
531	nr = n;
532	} else {
533	nr = num_online_cpus() + 1 + n;
534	if (nr <= 0)
535	nr = 1;
536	}
537	return nr;
538	}
539
540	/*
541	* RCU perf shutdown kthread. Just waits to be awakened, then shuts
542	* down system.
543	*/
544	static int
545	rcu_perf_shutdown(void *arg)
546	{
547	do {
548	wait_event(shutdown_wq,
549	atomic_read(&n_rcu_perf_writer_finished) >=
550	nrealwriters);
551	} while (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters);
552	smp_mb(); /* Wake before output. */
553	rcu_perf_cleanup();
554	kernel_power_off();
555	return -EINVAL;
556	}
557
558	static int __init
559	rcu_perf_init(void)
560	{
561	long i;
562	int firsterr = 0;
563	static struct rcu_perf_ops *perf_ops[] = {
564	&rcu_ops, &rcu_bh_ops, &srcu_ops, &sched_ops,
565	RCUPERF_TASKS_OPS
566	};
567
568	if (!torture_init_begin(perf_type, verbose, &perf_runnable))
569	return -EBUSY;
570
571	/* Process args and tell the world that the perf'er is on the job. */
572	for (i = 0; i < ARRAY_SIZE(perf_ops); i++) {
573	cur_ops = perf_ops[i];
574	if (strcmp(perf_type, cur_ops->name) == 0)
575	break;
576	}
577	if (i == ARRAY_SIZE(perf_ops)) {
578	pr_alert("rcu-perf: invalid perf type: \"%s\"\n",
579	perf_type);
580	pr_alert("rcu-perf types:");
581	for (i = 0; i < ARRAY_SIZE(perf_ops); i++)
582	pr_alert(" %s", perf_ops[i]->name);
583	pr_alert("\n");
584	firsterr = -EINVAL;
585	goto unwind;
586	}
587	if (cur_ops->init)
588	cur_ops->init();
589
590	nrealwriters = compute_real(nwriters);
591	nrealreaders = compute_real(nreaders);
592	atomic_set(&n_rcu_perf_reader_started, 0);
593	atomic_set(&n_rcu_perf_writer_started, 0);
594	atomic_set(&n_rcu_perf_writer_finished, 0);
595	rcu_perf_print_module_parms(cur_ops, "Start of test");
596
597	/* Start up the kthreads. */
598
599	if (shutdown) {
600	init_waitqueue_head(&shutdown_wq);
601	firsterr = torture_create_kthread(rcu_perf_shutdown, NULL,
602	shutdown_task);
603	if (firsterr)
604	goto unwind;
605	schedule_timeout_uninterruptible(1);
606	}
607	reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
608	GFP_KERNEL);
609	if (reader_tasks == NULL) {
610	VERBOSE_PERFOUT_ERRSTRING("out of memory");
611	firsterr = -ENOMEM;
612	goto unwind;
613	}
614	for (i = 0; i < nrealreaders; i++) {
6b558c4c	615	firsterr = torture_create_kthread(rcu_perf_reader, (void *)i,
8704baab PM	616	reader_tasks[i]);
	617	if (firsterr)
	618	goto unwind;
	619	}
	620	while (atomic_read(&n_rcu_perf_reader_started) < nrealreaders)
	621	schedule_timeout_uninterruptible(1);
	622	writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
	623	GFP_KERNEL);
	624	writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
	625	GFP_KERNEL);
	626	writer_n_durations =
	627	kcalloc(nrealwriters, sizeof(*writer_n_durations),
	628	GFP_KERNEL);
	629	if (!writer_tasks \|\| !writer_durations \|\| !writer_n_durations) {
	630	VERBOSE_PERFOUT_ERRSTRING("out of memory");
	631	firsterr = -ENOMEM;
	632	goto unwind;
	633	}
	634	for (i = 0; i < nrealwriters; i++) {
	635	writer_durations[i] =
	636	kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
	637	GFP_KERNEL);
	638	if (!writer_durations[i])
	639	goto unwind;
	640	firsterr = torture_create_kthread(rcu_perf_writer, (void *)i,
	641	writer_tasks[i]);
	642	if (firsterr)
	643	goto unwind;
	644	}
	645	torture_init_end();
	646	return 0;
	647
	648	unwind:
	649	torture_init_end();
	650	rcu_perf_cleanup();
	651	return firsterr;
	652	}
	653
	654	module_init(rcu_perf_init);
	655	module_exit(rcu_perf_cleanup);