[PATCH 2.6.28-rc4]lock_stat: Add "con-hungry" to show that how many person-time fight for the ticket spinlock
From: Yang Xi
Date: Tue Nov 18 2008 - 06:01:18 EST
Because the implementation of X86 spinlock adopts ticket lock, we can
know how many threads are waiting for the lock when there is a
contention on the spinlock. We add the number of these threads to the
bounces[bounce_hungry] and name "bounces[bounce_hungry]" as
"con-hungry". Finally, we can use this number to show that "the number
of threads waiting for a spinlock/ a contention". From it, we can know
that whether it is valuable to replace the spinlock with more
scalable spinlock since the design principle of scalability spinlock
is to decrease the cache invalid cost, if the "con-hungry/contentions"
is not high, we cannot benefit from more scalable spinlocks.
Signed-off-by: Yang Xi <hiyangxi@xxxxxxxxx>
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 331e5f1..a71398e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -136,6 +136,7 @@ enum bounce_type {
bounce_acquired_read,
bounce_contended_write,
bounce_contended_read,
+ bounce_hungry,
nr_bounce_types,
bounce_acquired = bounce_acquired_write,
@@ -165,6 +166,7 @@ struct lockdep_map {
const char *name;
#ifdef CONFIG_LOCK_STAT
int cpu;
+ int isspinlock;
#endif
};
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 06e1571..b3314ed 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3000,6 +3000,20 @@ __lock_contended(struct lockdep_map *lock,
unsigned long ip)
struct lock_class_stats *stats;
unsigned int depth;
int i, point;
+ spinlock_t * lock_ptr;
+ unsigned long hungry;
+
+ if (lock->isspinlock){
+ lock_ptr = container_of(lock,spinlock_t,dep_map);
+
+#if (NR_CPUS < 256)
+ hungry=(unsigned
char)((lock_ptr->raw_lock.slock>>8&0xff)-(lock_ptr->raw_lock.slock&0xff));
+
+#else
+ hungry=(unsigned
short)((lock_ptr->raw_lock.slock>>16&0xffff)-(lock_ptr->raw_lock.slock&0xffff));
+
+#endif
+ }
depth = curr->lockdep_depth;
if (DEBUG_LOCKS_WARN_ON(!depth))
@@ -3030,9 +3044,13 @@ found_it:
stats->contention_point[point]++;
if (lock->cpu != smp_processor_id())
stats->bounces[bounce_contended + !!hlock->read]++;
+ if (lock->isspinlock){
+ stats->bounces[bounce_hungry]+=hungry+1;
+ }
put_lock_stats(stats);
}
+
static void
__lock_acquired(struct lockdep_map *lock)
{
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 20dbcbf..2fc3ca0 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -534,7 +534,8 @@ 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_printf(m, "%14lu ",
stats->bounces[bounce_contended_write]);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_hungry]);
seq_lock_time(m, &stats->write_waittime);
seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
seq_lock_time(m, &stats->write_holdtime);
@@ -584,10 +585,11 @@ static void seq_header(struct seq_file *m)
{
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 "
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
"%14s %14s\n",
"class name",
"con-bounces",
+ "con-hungry",
"contentions",
"waittime-min",
"waittime-max",
@@ -597,7 +599,7 @@ static void seq_header(struct seq_file *m)
"holdtime-min",
"holdtime-max",
"holdtime-total");
- seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+ seq_line(m, '-', 0, 40 + 1 + 11 * (14 + 1));
seq_printf(m, "\n");
}
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index 9c4b025..2ec34ec 100644
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -27,6 +27,10 @@ void __spin_lock_init(spinlock_t *lock, const char *name,
lock->magic = SPINLOCK_MAGIC;
lock->owner = SPINLOCK_OWNER_INIT;
lock->owner_cpu = -1;
+ lock->dep_map.isspinlock = 0;
+#if ((defined(CONFIG_X86) || defined(CONFIG_X86_64))&&
defined(CONFIG_LOCK_STAT))
+ lock->dep_map.isspinlock = 1;
+#endif
}
EXPORT_SYMBOL(__spin_lock_init);
coder@coder-desktop:~/work/linux/linux-2.6$ git diff -u -p
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 331e5f1..a71398e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -136,6 +136,7 @@ enum bounce_type {
bounce_acquired_read,
bounce_contended_write,
bounce_contended_read,
+ bounce_hungry,
nr_bounce_types,
bounce_acquired = bounce_acquired_write,
@@ -165,6 +166,7 @@ struct lockdep_map {
const char *name;
#ifdef CONFIG_LOCK_STAT
int cpu;
+ int isspinlock;
#endif
};
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 06e1571..b3314ed 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3000,6 +3000,20 @@ __lock_contended(struct lockdep_map *lock,
unsigned long ip)
struct lock_class_stats *stats;
unsigned int depth;
int i, point;
+ spinlock_t * lock_ptr;
+ unsigned long hungry;
+
+ if (lock->isspinlock){
+ lock_ptr = container_of(lock,spinlock_t,dep_map);
+
+#if (NR_CPUS < 256)
+ hungry=(unsigned
char)((lock_ptr->raw_lock.slock>>8&0xff)-(lock_ptr->raw_lock.slock&0xff));
+
+#else
+ hungry=(unsigned
short)((lock_ptr->raw_lock.slock>>16&0xffff)-(lock_ptr->raw_lock.slock&0xffff));
+
+#endif
+ }
depth = curr->lockdep_depth;
if (DEBUG_LOCKS_WARN_ON(!depth))
@@ -3030,9 +3044,13 @@ found_it:
stats->contention_point[point]++;
if (lock->cpu != smp_processor_id())
stats->bounces[bounce_contended + !!hlock->read]++;
+ if (lock->isspinlock){
+ stats->bounces[bounce_hungry]+=hungry+1;
+ }
put_lock_stats(stats);
}
+
static void
__lock_acquired(struct lockdep_map *lock)
{
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 20dbcbf..2fc3ca0 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -534,7 +534,8 @@ 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_printf(m, "%14lu ",
stats->bounces[bounce_contended_write]);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_hungry]);
seq_lock_time(m, &stats->write_waittime);
seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
seq_lock_time(m, &stats->write_holdtime);
@@ -584,10 +585,11 @@ static void seq_header(struct seq_file *m)
{
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 "
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
"%14s %14s\n",
"class name",
"con-bounces",
+ "con-hungry",
"contentions",
"waittime-min",
"waittime-max",
@@ -597,7 +599,7 @@ static void seq_header(struct seq_file *m)
"holdtime-min",
"holdtime-max",
"holdtime-total");
- seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+ seq_line(m, '-', 0, 40 + 1 + 11 * (14 + 1));
seq_printf(m, "\n");
}
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index 9c4b025..2ec34ec 100644
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -27,6 +27,10 @@ void __spin_lock_init(spinlock_t *lock, const char *name,
lock->magic = SPINLOCK_MAGIC;
lock->owner = SPINLOCK_OWNER_INIT;
lock->owner_cpu = -1;
+ lock->dep_map.isspinlock = 0;
+#if ((defined(CONFIG_X86) || defined(CONFIG_X86_64))&&
defined(CONFIG_LOCK_STAT))
+ lock->dep_map.isspinlock = 1;
+#endif
}
EXPORT_SYMBOL(__spin_lock_init);
--
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