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Date: Wed, 23 Sep 2009 12:46:39 +1000
From: coder <yangxilkm@...il.com>
To: Ingo Molnar <mingo@...e.hu>
Cc: Daniel Walker <dwalker@...o99.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH]lock_stat: Adding "nr_contender" and "max_contender" to
show the degree of contention on ticket spinlock
Thanks Danlel. Here is the patch generated by git format-patch.
Signed-off-by: Yang Xi <yangxilkm@...il.com>
---
arch/x86/include/asm/spinlock.h | 9 +++++++++
include/linux/lockdep.h | 2 ++
include/linux/spinlock.h | 4 ++++
kernel/lockdep.c | 21 ++++++++++++++++++++-
kernel/lockdep_proc.c | 8 ++++++--
5 files changed, 41 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 4e77853..a2396d8 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -172,6 +172,15 @@ static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1;
}
+static inline int __ticket_spin_nr_contender(raw_spinlock_t *lock)
+{
+ int tmp = ACCESS_ONCE(lock->slock);
+
+ return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) + 1;
+}
+
+#define spin_nr_contender(lock) __ticket_spin_nr_contender(&(lock)->raw_lock)
+
#ifndef CONFIG_PARAVIRT_SPINLOCKS
static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 9ccf0e2..0627706 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -106,6 +106,8 @@ enum bounce_type {
bounce_acquired_read,
bounce_contended_write,
bounce_contended_read,
+ nr_contender,
+ max_contender,
nr_bounce_types,
bounce_acquired = bounce_acquired_write,
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index f0ca7a7..3d86966 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -132,6 +132,10 @@ do { \
#endif /*__raw_spin_is_contended*/
#endif
+#ifndef spin_nr_contender
+#define spin_nr_contender(lock) (spin_is_contended(lock) ? 1 : 0)
+#endif
+
/* The lock does not imply full memory barrier. */
#ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
static inline void smp_mb__after_lock(void) { smp_mb(); }
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index f74d2d7..e4b9f80 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -200,8 +200,14 @@ 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++)
+ for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) {
+ if (i == max_contender) {
+ if (stats.bounces[i] < pcs->bounces[i])
+ stats.bounces[i] = pcs->bounces[i];
+ continue;
+ }
stats.bounces[i] += pcs->bounces[i];
+ }
}
return stats;
@@ -3293,9 +3299,15 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
struct task_struct *curr = current;
struct held_lock *hlock, *prev_hlock;
struct lock_class_stats *stats;
+ unsigned long contender;
+ spinlock_t *lock_ptr;
unsigned int depth;
int i, contention_point, contending_point;
+ lock_ptr = container_of(lock, spinlock_t, dep_map);
+ if (lock_ptr->magic == SPINLOCK_MAGIC)
+ contender = spin_nr_contender(lock_ptr);
+
depth = curr->lockdep_depth;
if (DEBUG_LOCKS_WARN_ON(!depth))
return;
@@ -3332,6 +3344,13 @@ found_it:
stats->contending_point[contending_point]++;
if (lock->cpu != smp_processor_id())
stats->bounces[bounce_contended + !!hlock->read]++;
+
+ if (lock_ptr->magic == SPINLOCK_MAGIC) {
+ stats->bounces[nr_contender] += contender;
+ if (stats->bounces[max_contender] < contender)
+ stats->bounces[max_contender] = contender;
+ }
+
put_lock_stats(stats);
}
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index d4b3dbc..a3d0910 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -472,6 +472,8 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
seq_printf(m, "%40s:", name);
seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
+ seq_printf(m, "%14lu ", stats->bounces[nr_contender]);
+ seq_printf(m, "%14lu ", stats->bounces[max_contender]);
seq_lock_time(m, &stats->write_waittime);
seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
seq_lock_time(m, &stats->write_holdtime);
@@ -541,11 +543,13 @@ static void seq_header(struct seq_file *m)
if (unlikely(!debug_locks))
seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
- seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
- seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
+ seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
"%14s %14s\n",
"class name",
"con-bounces",
+ "nr-contender",
+ "contender-max",
"contentions",
"waittime-min",
"waittime-max",
--
1.6.0.4
--
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