cregit-Linux how code gets into the kernel

Release 4.14 tools/perf/builtin-lock.c

Directory: tools/perf
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <inttypes.h>
#include "builtin.h"
#include "perf.h"

#include "util/evlist.h"
#include "util/evsel.h"
#include "util/util.h"
#include "util/cache.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/header.h"

#include <subcmd/parse-options.h>
#include "util/trace-event.h"

#include "util/debug.h"
#include "util/session.h"
#include "util/tool.h"
#include "util/data.h"

#include <sys/types.h>
#include <sys/prctl.h>
#include <semaphore.h>
#include <pthread.h>
#include <math.h>
#include <limits.h>

#include <linux/list.h>
#include <linux/hash.h>
#include <linux/kernel.h>


static struct perf_session *session;

/* based on kernel/lockdep.c */

#define LOCKHASH_BITS		12

#define LOCKHASH_SIZE		(1UL << LOCKHASH_BITS)


static struct list_head lockhash_table[LOCKHASH_SIZE];


#define __lockhashfn(key)	hash_long((unsigned long)key, LOCKHASH_BITS)

#define lockhashentry(key)	(lockhash_table + __lockhashfn((key)))


struct lock_stat {
	
struct list_head	hash_entry;
	
struct rb_node		rb;		/* used for sorting */

	/*
         * FIXME: perf_evsel__intval() returns u64,
         * so address of lockdep_map should be dealed as 64bit.
         * Is there more better solution?
         */
	
void			*addr;		/* address of lockdep_map, used as ID */
	
char			*name;		/* for strcpy(), we cannot use const */

	
unsigned int		nr_acquire;
	
unsigned int		nr_acquired;
	
unsigned int		nr_contended;
	
unsigned int		nr_release;

	
unsigned int		nr_readlock;
	
unsigned int		nr_trylock;

	/* these times are in nano sec. */
	
u64                     avg_wait_time;
	
u64			wait_time_total;
	
u64			wait_time_min;
	
u64			wait_time_max;

	
int			discard; /* flag of blacklist */
};

/*
 * States of lock_seq_stat
 *
 * UNINITIALIZED is required for detecting first event of acquire.
 * As the nature of lock events, there is no guarantee
 * that the first event for the locks are acquire,
 * it can be acquired, contended or release.
 */

#define SEQ_STATE_UNINITIALIZED      0	       
/* initial state */

#define SEQ_STATE_RELEASED	1

#define SEQ_STATE_ACQUIRING	2

#define SEQ_STATE_ACQUIRED	3

#define SEQ_STATE_READ_ACQUIRED	4

#define SEQ_STATE_CONTENDED	5

/*
 * MAX_LOCK_DEPTH
 * Imported from include/linux/sched.h.
 * Should this be synchronized?
 */

#define MAX_LOCK_DEPTH 48

/*
 * struct lock_seq_stat:
 * Place to put on state of one lock sequence
 * 1) acquire -> acquired -> release
 * 2) acquire -> contended -> acquired -> release
 * 3) acquire (with read or try) -> release
 * 4) Are there other patterns?
 */

struct lock_seq_stat {
	
struct list_head        list;
	
int			state;
	
u64			prev_event_time;
	
void                    *addr;

	
int                     read_count;
};


struct thread_stat {
	
struct rb_node		rb;

	
u32                     tid;
	
struct list_head        seq_list;
};


static struct rb_root		thread_stats;




static struct thread_stat *thread_stat_find(u32 tid)
{
	struct rb_node *node;
	struct thread_stat *st;

	node = thread_stats.rb_node;
	while (node) {
		st = container_of(node, struct thread_stat, rb);
		if (st->tid == tid)
			return st;
		else if (tid < st->tid)
			node = node->rb_left;
		else
			node = node->rb_right;
	}

	return NULL;
}


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static void thread_stat_insert(struct thread_stat *new)
{
	struct rb_node **rb = &thread_stats.rb_node;
	struct rb_node *parent = NULL;
	struct thread_stat *p;

	while (*rb) {
		p = container_of(*rb, struct thread_stat, rb);
		parent = *rb;

		if (new->tid < p->tid)
			rb = &(*rb)->rb_left;
		else if (new->tid > p->tid)
			rb = &(*rb)->rb_right;
		else
			BUG_ON("inserting invalid thread_stat\n");
	}

	rb_link_node(&new->rb, parent, rb);
	rb_insert_color(&new->rb, &thread_stats);
}


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static struct thread_stat *thread_stat_findnew_after_first(u32 tid)
{
	struct thread_stat *st;

	st = thread_stat_find(tid);
	if (st)
		return st;

	st = zalloc(sizeof(struct thread_stat));
	if (!st) {
		pr_err("memory allocation failed\n");
		return NULL;
	}

	st->tid = tid;
	INIT_LIST_HEAD(&st->seq_list);

	thread_stat_insert(st);

	return st;
}


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static struct thread_stat *thread_stat_findnew_first(u32 tid);

static struct thread_stat *(*thread_stat_findnew)(u32 tid) =
	thread_stat_findnew_first;




static struct thread_stat *thread_stat_findnew_first(u32 tid)
{
	struct thread_stat *st;

	st = zalloc(sizeof(struct thread_stat));
	if (!st) {
		pr_err("memory allocation failed\n");
		return NULL;
	}
	st->tid = tid;
	INIT_LIST_HEAD(&st->seq_list);

	rb_link_node(&st->rb, NULL, &thread_stats.rb_node);
	rb_insert_color(&st->rb, &thread_stats);

	thread_stat_findnew = thread_stat_findnew_after_first;
	return st;
}


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/* build simple key function one is bigger than two */

#define SINGLE_KEY(member)						\
	static int lock_stat_key_ ## member(struct lock_stat *one,      \
                                         struct lock_stat *two)         \
        {                                                               \
                return one->member > two->member;                       \
        }

SINGLE_KEY(nr_acquired)
SINGLE_KEY(nr_contended)
SINGLE_KEY(avg_wait_time)
SINGLE_KEY(wait_time_total)
SINGLE_KEY(wait_time_max)




static int lock_stat_key_wait_time_min(struct lock_stat *one,
					struct lock_stat *two)
{
	u64 s1 = one->wait_time_min;
	u64 s2 = two->wait_time_min;
	if (s1 == ULLONG_MAX)
		s1 = 0;
	if (s2 == ULLONG_MAX)
		s2 = 0;
	return s1 > s2;
}


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struct lock_key {
	/*
         * name: the value for specify by user
         * this should be simpler than raw name of member
         * e.g. nr_acquired -> acquired, wait_time_total -> wait_total
         */
	
const char		*name;
	
int			(*key)(struct lock_stat*, struct lock_stat*);
};


static const char		*sort_key = "acquired";


static int			(*compare)(struct lock_stat *, struct lock_stat *);


static struct rb_root		result;	
/* place to store sorted data */


#define DEF_KEY_LOCK(name, fn_suffix)	\
	{ #name, lock_stat_key_ ## fn_suffix }

struct lock_key keys[] = {
	DEF_KEY_LOCK(acquired, nr_acquired),
	DEF_KEY_LOCK(contended, nr_contended),
	DEF_KEY_LOCK(avg_wait, avg_wait_time),
	DEF_KEY_LOCK(wait_total, wait_time_total),
	DEF_KEY_LOCK(wait_min, wait_time_min),
	DEF_KEY_LOCK(wait_max, wait_time_max),

	/* extra comparisons much complicated should be here */

	{ NULL, NULL }
};




static int select_key(void)
{
	int i;

	for (i = 0; keys[i].name; i++) {
		if (!strcmp(keys[i].name, sort_key)) {
			compare = keys[i].key;
			return 0;
		}
	}

	pr_err("Unknown compare key: %s\n", sort_key);

	return -1;
}


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static void insert_to_result(struct lock_stat *st,
			     int (*bigger)(struct lock_stat *, struct lock_stat *))
{
	struct rb_node **rb = &result.rb_node;
	struct rb_node *parent = NULL;
	struct lock_stat *p;

	while (*rb) {
		p = container_of(*rb, struct lock_stat, rb);
		parent = *rb;

		if (bigger(st, p))
			rb = &(*rb)->rb_left;
		else
			rb = &(*rb)->rb_right;
	}

	rb_link_node(&st->rb, parent, rb);
	rb_insert_color(&st->rb, &result);
}


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/* returns left most element of result, and erase it */



static struct lock_stat *pop_from_result(void)
{
	struct rb_node *node = result.rb_node;

	if (!node)
		return NULL;

	while (node->rb_left)
		node = node->rb_left;

	rb_erase(node, &result);
	return container_of(node, struct lock_stat, rb);
}


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static struct lock_stat *lock_stat_findnew(void *addr, const char *name)
{
	struct list_head *entry = lockhashentry(addr);
	struct lock_stat *ret, *new;

	list_for_each_entry(ret, entry, hash_entry) {
		if (ret->addr == addr)
			return ret;
	}

	new = zalloc(sizeof(struct lock_stat));
	if (!new)
		goto alloc_failed;

	new->addr = addr;
	new->name = zalloc(sizeof(char) * strlen(name) + 1);
	if (!new->name) {
		free(new);
		goto alloc_failed;
	}

	strcpy(new->name, name);
	new->wait_time_min = ULLONG_MAX;

	list_add(&new->hash_entry, entry);
	return new;

alloc_failed:
	pr_err("memory allocation failed\n");
	return NULL;
}


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struct trace_lock_handler {
	
int (*acquire_event)(struct perf_evsel *evsel,
			     struct perf_sample *sample);

	
int (*acquired_event)(struct perf_evsel *evsel,
			      struct perf_sample *sample);

	
int (*contended_event)(struct perf_evsel *evsel,
			       struct perf_sample *sample);

	
int (*release_event)(struct perf_evsel *evsel,
			     struct perf_sample *sample);
};




static struct lock_seq_stat *get_seq(struct thread_stat *ts, void *addr)
{
	struct lock_seq_stat *seq;

	list_for_each_entry(seq, &ts->seq_list, list) {
		if (seq->addr == addr)
			return seq;
	}

	seq = zalloc(sizeof(struct lock_seq_stat));
	if (!seq) {
		pr_err("memory allocation failed\n");
		return NULL;
	}
	seq->state = SEQ_STATE_UNINITIALIZED;
	seq->addr = addr;

	list_add(&seq->list, &ts->seq_list);
	return seq;
}


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enum broken_state {
	
BROKEN_ACQUIRE,
	
BROKEN_ACQUIRED,
	
BROKEN_CONTENDED,
	
BROKEN_RELEASE,
	
BROKEN_MAX,
};


static int bad_hist[BROKEN_MAX];


enum acquire_flags {
	
TRY_LOCK = 1,
	
READ_LOCK = 2,
};




static int report_lock_acquire_event(struct perf_evsel *evsel,
				     struct perf_sample *sample)
{
	void *addr;
	struct lock_stat *ls;
	struct thread_stat *ts;
	struct lock_seq_stat *seq;
	const char *name = perf_evsel__strval(evsel, sample, "name");
	u64 tmp = perf_evsel__intval(evsel, sample, "lockdep_addr");
	int flag = perf_evsel__intval(evsel, sample, "flag");

	memcpy(&addr, &tmp, sizeof(void *));

	ls = lock_stat_findnew(addr, name);
	if (!ls)
		return -ENOMEM;
	if (ls->discard)
		return 0;

	ts = thread_stat_findnew(sample->tid);
	if (!ts)
		return -ENOMEM;

	seq = get_seq(ts, addr);
	if (!seq)
		return -ENOMEM;

	switch (seq->state) {
	case SEQ_STATE_UNINITIALIZED:
	case SEQ_STATE_RELEASED:
		if (!flag) {
			seq->state = SEQ_STATE_ACQUIRING;
		} else {
			if (flag & TRY_LOCK)
				ls->nr_trylock++;
			if (flag & READ_LOCK)
				ls->nr_readlock++;
			seq->state = SEQ_STATE_READ_ACQUIRED;
			seq->read_count = 1;
			ls->nr_acquired++;
		}
		break;
	case SEQ_STATE_READ_ACQUIRED:
		if (flag & READ_LOCK) {
			seq->read_count++;
			ls->nr_acquired++;
			goto end;
		} else {
			goto broken;
		}
		break;
	case SEQ_STATE_ACQUIRED:
	case SEQ_STATE_ACQUIRING:
	case SEQ_STATE_CONTENDED:
broken:
		/* broken lock sequence, discard it */
		ls->discard = 1;
		bad_hist[BROKEN_ACQUIRE]++;
		list_del(&seq->list);
		free(seq);
		goto end;
	default:
		BUG_ON("Unknown state of lock sequence found!\n");
		break;
	}

	ls->nr_acquire++;
	seq->prev_event_time = sample->time;
end:
	return 0;
}


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Davidlohr Bueso A30.95%111.11%


Ingo Molnar10.32%111.11%


Total317100.00%9100.00%






static int report_lock_acquired_event(struct perf_evsel *evsel,
				      struct perf_sample *sample)
{
	void *addr;
	struct lock_stat *ls;
	struct thread_stat *ts;
	struct lock_seq_stat *seq;
	u64 contended_term;
	const char *name = perf_evsel__strval(evsel, sample, "name");
	u64 tmp = perf_evsel__intval(evsel, sample, "lockdep_addr");

	memcpy(&addr, &tmp, sizeof(void *));

	ls = lock_stat_findnew(addr, name);
	if (!ls)
		return -ENOMEM;
	if (ls->discard)
		return 0;

	ts = thread_stat_findnew(sample->tid);
	if (!ts)
		return -ENOMEM;

	seq = get_seq(ts, addr);
	if (!seq)
		return -ENOMEM;

	switch (seq->state) {
	case SEQ_STATE_UNINITIALIZED:
		/* orphan event, do nothing */
		return 0;
	case SEQ_STATE_ACQUIRING:
		break;
	case SEQ_STATE_CONTENDED:
		contended_term = sample->time - seq->prev_event_time;
		ls->wait_time_total += contended_term;
		if (contended_term < ls->wait_time_min)
			ls->wait_time_min = contended_term;
		if (ls->wait_time_max < contended_term)
			ls->wait_time_max = contended_term;
		break;
	case SEQ_STATE_RELEASED:
	case SEQ_STATE_ACQUIRED:
	case SEQ_STATE_READ_ACQUIRED:
		/* broken lock sequence, discard it */
		ls->discard = 1;
		bad_hist[BROKEN_ACQUIRED]++;
		list_del(&seq->list);
		free(seq);
		goto end;
	default:
		BUG_ON("Unknown state of lock sequence found!\n");
		break;
	}

	seq->state = SEQ_STATE_ACQUIRED;
	ls->nr_acquired++;
	ls->avg_wait_time = ls->nr_contended ? ls->wait_time_total/ls->nr_contended : 0;
	seq->prev_event_time = sample->time;
end:
	return 0;
}


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David Ahern3411.49%111.11%


Davidlohr Bueso A217.09%222.22%


Ingo Molnar10.34%111.11%


Frédéric Weisbecker10.34%111.11%


Total296100.00%9100.00%






static int report_lock_contended_event(struct perf_evsel *evsel,
				       struct perf_sample *sample)
{
	void *addr;
	struct lock_stat *ls;
	struct thread_stat *ts;
	struct lock_seq_stat *seq;
	const char *name = perf_evsel__strval(evsel, sample, "name");
	u64 tmp = perf_evsel__intval(evsel, sample, "lockdep_addr");

	memcpy(&addr, &tmp, sizeof(void *));

	ls = lock_stat_findnew(addr, name);
	if (!ls)
		return -ENOMEM;
	if (ls->discard)
		return 0;

	ts = thread_stat_findnew(sample->tid);
	if (!ts)
		return -ENOMEM;

	seq = get_seq(ts, addr);
	if (!seq)
		return -ENOMEM;

	switch (seq->state) {
	case SEQ_STATE_UNINITIALIZED:
		/* orphan event, do nothing */
		return 0;
	case SEQ_STATE_ACQUIRING:
		break;
	case SEQ_STATE_RELEASED:
	case SEQ_STATE_ACQUIRED:
	case SEQ_STATE_READ_ACQUIRED:
	case SEQ_STATE_CONTENDED:
		/* broken lock sequence, discard it */
		ls->discard = 1;
		bad_hist[BROKEN_CONTENDED]++;
		list_del(&seq->list);
		free(seq);
		goto end;
	default:
		BUG_ON("Unknown state of lock sequence found!\n");
		break;
	}

	seq->state = SEQ_STATE_CONTENDED;
	ls->nr_contended++;
	ls->avg_wait_time = ls->wait_time_total/ls->nr_contended;
	seq->prev_event_time = sample->time;
end:
	return 0;
}


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Davidlohr Bueso A156.20%222.22%


Ingo Molnar10.41%111.11%


Frédéric Weisbecker10.41%111.11%


Total242100.00%9100.00%






static int report_lock_release_event(struct perf_evsel *evsel,
				     struct perf_sample *sample)
{
	void *addr;
	struct lock_stat *ls;
	struct thread_stat *ts;
	struct lock_seq_stat *seq;
	const char *name = perf_evsel__strval(evsel, sample, "name");
	u64 tmp = perf_evsel__intval(evsel, sample, "lockdep_addr");

	memcpy(&addr, &tmp, sizeof(void *));

	ls = lock_stat_findnew(addr, name);
	if (!ls)
		return -ENOMEM;
	if (ls->discard)
		return 0;

	ts = thread_stat_findnew(sample->tid);
	if (!ts)
		return -ENOMEM;

	seq = get_seq(ts, addr);
	if (!seq)
		return -ENOMEM;

	switch (seq->state) {
	case SEQ_STATE_UNINITIALIZED:
		goto end;
	case SEQ_STATE_ACQUIRED:
		break;
	case SEQ_STATE_READ_ACQUIRED:
		seq->read_count--;
		BUG_ON(seq->read_count < 0);
		if (!seq->read_count) {
			ls->nr_release++;
			goto end;
		}
		break;
	case SEQ_STATE_ACQUIRING:
	case SEQ_STATE_CONTENDED:
	case SEQ_STATE_RELEASED:
		/* broken lock sequence, discard it */
		ls->discard = 1;
		bad_hist[BROKEN_RELEASE]++;
		goto free_seq;
	default:
		BUG_ON("Unknown state of lock sequence found!\n");
		break;
	}

	ls->nr_release++;
free_seq:
	list_del(&seq->list);
	free(seq);
end:
	return 0;
}


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Davidlohr Bueso A31.20%112.50%


Frédéric Weisbecker10.40%112.50%


Ingo Molnar10.40%112.50%


Total249100.00%8100.00%



/* lock oriented handlers */
/* TODO: handlers for CPU oriented, thread oriented */

static struct trace_lock_handler report_lock_ops  = {
	.acquire_event		= report_lock_acquire_event,
	.acquired_event		= report_lock_acquired_event,
	.contended_event	= report_lock_contended_event,
	.release_event		= report_lock_release_event,
};


static struct trace_lock_handler *trace_handler;




static int perf_evsel__process_lock_acquire(struct perf_evsel *evsel,
					     struct perf_sample *sample)
{
	if (trace_handler->acquire_event)
		return trace_handler->acquire_event(evsel, sample);
	return 0;
}


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David Ahern411.43%125.00%


Total35100.00%4100.00%






static int perf_evsel__process_lock_acquired(struct perf_evsel *evsel,
					      struct perf_sample *sample)
{
	if (trace_handler->acquired_event)
		return trace_handler->acquired_event(evsel, sample);
	return 0;
}


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static int perf_evsel__process_lock_contended(struct perf_evsel *evsel,
					      struct perf_sample *sample)
{
	if (trace_handler->contended_event)
		return trace_handler->contended_event(evsel, sample);
	return 0;
}


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Total35100.00%5100.00%






static int perf_evsel__process_lock_release(struct perf_evsel *evsel,
					    struct perf_sample *sample)
{
	if (trace_handler->release_event)
		return trace_handler->release_event(evsel, sample);
	return 0;
}


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David Ahern25.71%125.00%


Total35100.00%4100.00%






static void print_bad_events(int bad, int total)
{
	/* Output for debug, this have to be removed */
	int i;
	const char *name[4] =
		{ "acquire", "acquired", "contended", "release" };

	pr_info("\n=== output for debug===\n\n");
	pr_info("bad: %d, total: %d\n", bad