Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=96645678cd726e87ce42a0664de71e047e32bca4
Commit: 96645678cd726e87ce42a0664de71e047e32bca4
Parent: 443aef0eddfa44c158d1b94ebb431a70638fcab4
Author: Peter Zijlstra <[EMAIL PROTECTED]>
AuthorDate: Thu Jul 19 01:49:00 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Jul 19 10:04:49 2007 -0700
lockstat: measure lock bouncing
__acquire
|
lock _____
| \
| __contended
| |
| wait
| _______/
|/
|
__acquired
|
__release
|
unlock
We measure acquisition and contention bouncing.
This is done by recording a cpu stamp in each lock instance.
Contention bouncing requires the cpu stamp to be set on acquisition. Hence
we
move __acquired into the generic path.
__acquired is then used to measure acquisition bouncing by comparing the
current cpu with the old stamp before replacing it.
__contended is used to measure contention bouncing (only useful for
preemptable
locks)
[EMAIL PROTECTED]: cleanups]
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
include/linux/lockdep.h | 17 ++++++++++++++++-
kernel/lockdep.c | 38 ++++++++++++++++++++++++++------------
kernel/lockdep_proc.c | 19 ++++++++++++-------
kernel/mutex.c | 2 +-
4 files changed, 55 insertions(+), 21 deletions(-)
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 3d3386b..0e843bf 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -130,12 +130,24 @@ struct lock_time {
unsigned long nr;
};
+enum bounce_type {
+ bounce_acquired_write,
+ bounce_acquired_read,
+ bounce_contended_write,
+ bounce_contended_read,
+ nr_bounce_types,
+
+ bounce_acquired = bounce_acquired_write,
+ bounce_contended = bounce_contended_write,
+};
+
struct lock_class_stats {
unsigned long contention_point[4];
struct lock_time read_waittime;
struct lock_time write_waittime;
struct lock_time read_holdtime;
struct lock_time write_holdtime;
+ unsigned long bounces[nr_bounce_types];
};
struct lock_class_stats lock_stats(struct lock_class *class);
@@ -150,6 +162,9 @@ struct lockdep_map {
struct lock_class_key *key;
struct lock_class *class_cache;
const char *name;
+#ifdef CONFIG_LOCK_STAT
+ int cpu;
+#endif
};
/*
@@ -321,8 +336,8 @@ do {
\
if (!try(_lock)) { \
lock_contended(&(_lock)->dep_map, _RET_IP_); \
lock(_lock); \
- lock_acquired(&(_lock)->dep_map); \
} \
+ lock_acquired(&(_lock)->dep_map); \
} while (0)
#else /* CONFIG_LOCK_STAT */
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index cb64022..156fce4 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -177,6 +177,9 @@ struct lock_class_stats lock_stats(struct lock_class *class)
lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+ for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+ stats.bounces[i] += pcs->bounces[i];
}
return stats;
@@ -2325,6 +2328,9 @@ void lockdep_init_map(struct lockdep_map *lock, const
char *name,
lock->name = name;
lock->key = key;
lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+ lock->cpu = raw_smp_processor_id();
+#endif
if (subclass)
register_lock_class(lock, subclass, 1);
}
@@ -2775,6 +2781,8 @@ found_it:
stats = get_lock_stats(hlock->class);
if (point < ARRAY_SIZE(stats->contention_point))
stats->contention_point[i]++;
+ if (lock->cpu != smp_processor_id())
+ stats->bounces[bounce_contended + !!hlock->read]++;
put_lock_stats(stats);
}
@@ -2786,8 +2794,8 @@ __lock_acquired(struct lockdep_map *lock)
struct lock_class_stats *stats;
unsigned int depth;
u64 now;
- s64 waittime;
- int i;
+ s64 waittime = 0;
+ int i, cpu;
depth = curr->lockdep_depth;
if (DEBUG_LOCKS_WARN_ON(!depth))
@@ -2809,19 +2817,25 @@ __lock_acquired(struct lockdep_map *lock)
return;
found_it:
- if (!hlock->waittime_stamp)
- return;
-
- now = sched_clock();
- waittime = now - hlock->waittime_stamp;
- hlock->holdtime_stamp = now;
+ cpu = smp_processor_id();
+ if (hlock->waittime_stamp) {
+ now = sched_clock();
+ waittime = now - hlock->waittime_stamp;
+ hlock->holdtime_stamp = now;
+ }
stats = get_lock_stats(hlock->class);
- if (hlock->read)
- lock_time_inc(&stats->read_waittime, waittime);
- else
- lock_time_inc(&stats->write_waittime, waittime);
+ if (waittime) {
+ if (hlock->read)
+ lock_time_inc(&stats->read_waittime, waittime);
+ else
+ lock_time_inc(&stats->write_waittime, waittime);
+ }
+ if (lock->cpu != cpu)
+ stats->bounces[bounce_acquired + !!hlock->read]++;
put_lock_stats(stats);
+
+ lock->cpu = cpu;
}
void lock_contended(struct lockdep_map *lock, unsigned long ip)
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 39163ed..7ff8013 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -430,16 +430,18 @@ static void seq_stats(struct seq_file *m, struct
lock_stat_data *data)
else
seq_printf(m, "%40s:", name);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
seq_lock_time(m, &stats->write_waittime);
- seq_puts(m, " ");
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
seq_lock_time(m, &stats->write_holdtime);
seq_puts(m, "\n");
}
if (stats->read_holdtime.nr) {
seq_printf(m, "%38s-R:", name);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
seq_lock_time(m, &stats->read_waittime);
- seq_puts(m, " ");
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
seq_lock_time(m, &stats->read_holdtime);
seq_puts(m, "\n");
}
@@ -469,26 +471,29 @@ static void seq_stats(struct seq_file *m, struct
lock_stat_data *data)
}
if (i) {
seq_puts(m, "\n");
- seq_line(m, '.', 0, 40 + 1 + 8 * (14 + 1));
+ seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
seq_puts(m, "\n");
}
}
static void seq_header(struct seq_file *m)
{
- seq_printf(m, "lock_stat version 0.1\n");
- seq_line(m, '-', 0, 40 + 1 + 8 * (14 + 1));
- seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s\n",
+ seq_printf(m, "lock_stat version 0.2\n");
+ seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
+ "%14s %14s\n",
"class name",
+ "con-bounces",
"contentions",
"waittime-min",
"waittime-max",
"waittime-total",
+ "acq-bounces",
"acquisitions",
"holdtime-min",
"holdtime-max",
"holdtime-total");
- seq_line(m, '-', 0, 40 + 1 + 8 * (14 + 1));
+ seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
seq_printf(m, "\n");
}
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 7a3f327..691b865 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -180,8 +180,8 @@ __mutex_lock_common(struct mutex *lock, long state,
unsigned int subclass)
spin_lock_mutex(&lock->wait_lock, flags);
}
- lock_acquired(&lock->dep_map);
done:
+ lock_acquired(&lock->dep_map);
/* got the lock - rejoice! */
mutex_remove_waiter(lock, &waiter, task_thread_info(task));
debug_mutex_set_owner(lock, task_thread_info(task));
-
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