Commit 0d435bf8 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf lock: Add -c/--combine-locks option 



The -c or --combine-locks option is to merge lock instances in the
same class into a single entry.  It compares the name of the locks
and marks duplicated entries using lock_stat->combined.

 # perf lock report
                Name   acquired  contended   avg wait (ns) total wait (ns)   max wait (ns)   min wait (ns)

       rcu_read_lock     251225          0               0               0               0               0
 &(ei->i_block_re...       8731          0               0               0               0               0
 &sb->s_type->i_l...       8731          0               0               0               0               0
  hrtimer_bases.lock       5261          0               0               0               0               0
  hrtimer_bases.lock       2626          0               0               0               0               0
  hrtimer_bases.lock       1953          0               0               0               0               0
  hrtimer_bases.lock       1382          0               0               0               0               0
    cpu_hotplug_lock       1350          0               0               0               0               0
  hrtimer_bases.lock       1273          0               0               0               0               0
  hrtimer_bases.lock       1269          0               0               0               0               0

 # perf lock report -c
                Name   acquired  contended   avg wait (ns) total wait (ns)   max wait (ns)   min wait (ns)

       rcu_read_lock     251225          0               0               0               0               0
  hrtimer_bases.lock      39450          0               0               0               0               0
 &sb->s_type->i_l...      10301          1             662             662             662             662
    ptlock_ptr(page)      10173          2             701            1402             760             642
 &(ei->i_block_re...       8732          0               0               0               0               0
        &xa->xa_lock       8088          0               0               0               0               0
         &base->lock       6705          0               0               0               0               0
         &p->pi_lock       5549          0               0               0               0               0
 &dentry->d_lockr...       5010          4            1274            5097            1844             789
           &ep->lock       3958          0               0               0               0               0

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220127000050.3011493-6-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ba8a56c7

tools/perf/Documentation/perf-lock.txt

+4 −0
Original line number Diff line number Diff line
@@ -54,6 +54,10 @@ REPORT OPTIONS 
        Sorting key. Possible values: acquired (default), contended,

	avg_wait, wait_total, wait_max, wait_min.



-c::

--combine-locks::

	Merge lock instances in the same class (based on name).



INFO OPTIONS

------------

tools/perf/builtin-lock.c

+68 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ struct lock_stat { 
	u64			wait_time_max;



	int			discard; /* flag of blacklist */

	int			combined;

};



/*
@@ -115,6 +116,8 @@ struct thread_stat { 


static struct rb_root		thread_stats;



static bool combine_locks;



static struct thread_stat *thread_stat_find(u32 tid)

{

	struct rb_node *node;
@@ -241,6 +244,7 @@ static const char *sort_key = "acquired"; 


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



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

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



#define DEF_KEY_LOCK(name, fn_suffix)	\
@@ -274,6 +278,49 @@ static int select_key(void) 
	return -1;

}



static void combine_lock_stats(struct lock_stat *st)

{

	struct rb_node **rb = &sorted.rb_node;

	struct rb_node *parent = NULL;

	struct lock_stat *p;

	int ret;



	while (*rb) {

		p = container_of(*rb, struct lock_stat, rb);

		parent = *rb;



		if (st->name && p->name)

			ret = strcmp(st->name, p->name);

		else

			ret = !!st->name - !!p->name;



		if (ret == 0) {

			p->nr_acquired += st->nr_acquired;

			p->nr_contended += st->nr_contended;

			p->wait_time_total += st->wait_time_total;



			if (p->nr_contended)

				p->avg_wait_time = p->wait_time_total / p->nr_contended;



			if (p->wait_time_min > st->wait_time_min)

				p->wait_time_min = st->wait_time_min;

			if (p->wait_time_max < st->wait_time_max)

				p->wait_time_max = st->wait_time_max;



			st->combined = 1;

			return;

		}



		if (ret < 0)

			rb = &(*rb)->rb_left;

		else

			rb = &(*rb)->rb_right;

	}



	rb_link_node(&st->rb, parent, rb);

	rb_insert_color(&st->rb, &sorted);

}



static void insert_to_result(struct lock_stat *st,

			     int (*bigger)(struct lock_stat *, struct lock_stat *))

{
@@ -281,6 +328,9 @@ static void insert_to_result(struct lock_stat *st, 
	struct rb_node *parent = NULL;

	struct lock_stat *p;



	if (combine_locks && st->combined)

		return;



	while (*rb) {

		p = container_of(*rb, struct lock_stat, rb);

		parent = *rb;
@@ -833,6 +883,21 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused, 
	return err;

}



static void combine_result(void)

{

	unsigned int i;

	struct lock_stat *st;



	if (!combine_locks)

		return;



	for (i = 0; i < LOCKHASH_SIZE; i++) {

		hlist_for_each_entry(st, &lockhash_table[i], hash_entry) {

			combine_lock_stats(st);

		}

	}

}



static void sort_result(void)

{

	unsigned int i;
@@ -896,6 +961,7 @@ static int __cmd_report(bool display_info) 
	if (display_info) /* used for info subcommand */

		err = dump_info();

	else {

		combine_result();

		sort_result();

		print_result();

	}
@@ -970,6 +1036,8 @@ int cmd_lock(int argc, const char **argv) 
	OPT_STRING('k', "key", &sort_key, "acquired",

		    "key for sorting (acquired / contended / avg_wait / wait_total / wait_max / wait_min)"),

	/* TODO: type */

	OPT_BOOLEAN('c', "combine-locks", &combine_locks,

		    "combine locks in the same class"),

	OPT_PARENT(lock_options)

	};