The patch titled
lockstat: measure lock bouncing
has been removed from the -mm tree. Its filename was
lockstat-measure-lock-bouncing.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: lockstat: measure lock bouncing
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
__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)
[akpm@xxxxxxxxxxxxxxxxxxxx: cleanups]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 -puN include/linux/lockdep.h~lockstat-measure-lock-bouncing include/linux/lockdep.h
--- a/include/linux/lockdep.h~lockstat-measure-lock-bouncing
+++ a/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 -puN kernel/lockdep.c~lockstat-measure-lock-bouncing kernel/lockdep.c
--- a/kernel/lockdep.c~lockstat-measure-lock-bouncing
+++ a/kernel/lockdep.c
@@ -177,6 +177,9 @@ struct lock_class_stats lock_stats(struc
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->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 -puN kernel/lockdep_proc.c~lockstat-measure-lock-bouncing kernel/lockdep_proc.c
--- a/kernel/lockdep_proc.c~lockstat-measure-lock-bouncing
+++ a/kernel/lockdep_proc.c
@@ -430,16 +430,18 @@ static void seq_stats(struct seq_file *m
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
}
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 -puN kernel/mutex.c~lockstat-measure-lock-bouncing kernel/mutex.c
--- a/kernel/mutex.c~lockstat-measure-lock-bouncing
+++ a/kernel/mutex.c
@@ -180,8 +180,8 @@ __mutex_lock_common(struct mutex *lock,
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));
_
Patches currently in -mm which might be from a.p.zijlstra@xxxxxxxxx are
origin.patch
intel-iommu-dmar-detection-and-parsing-logic.patch
intel-iommu-pci-generic-helper-function.patch
intel-iommu-clflush_cache_range-now-takes-size-param.patch
intel-iommu-iova-allocation-and-management-routines.patch
intel-iommu-intel-iommu-driver.patch
intel-iommu-avoid-memory-allocation-failures-in-dma-map-api-calls.patch
intel-iommu-intel-iommu-cmdline-option-forcedac.patch
intel-iommu-dmar-fault-handling-support.patch
intel-iommu-iommu-gfx-workaround.patch
intel-iommu-iommu-floppy-workaround.patch
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