lockstat: Report avg wait and hold times (1232e380) · Commits · 戴 / test

Documentation/lockstat.txt

+61 −62

Original line number	Diff line number	Diff line
		@@ -47,15 +47,13 @@ With these hooks we provide the following statistics:
		wait time min - shortest (non-0) time we ever had to wait for a lock
		max - longest time we ever had to wait for a lock
		total - total time we spend waiting on this lock
		avg - average time spent waiting on this lock
		acq-bounces - number of lock acquisitions that involved x-cpu data
		acquisitions - number of times we took the lock
		hold time min - shortest (non-0) time we ever held the lock
		max - longest time we ever held the lock
		total - total time this lock was held

		From these number various other statistics can be derived, such as:

		hold time average = hold time total / acquisitions
		avg - average time this lock was held

		These numbers are gathered per lock class, per read/write state (when
		applicable).
		@@ -84,37 +82,38 @@ Look at the current lock statistics:

		# less /proc/lock_stat

		01 lock_stat version 0.3
		02 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
		03 class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
		04 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
		01 lock_stat version 0.4
		02-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
		03 class name con-bounces contentions waittime-min waittime-max waittime-total waittime-avg acq-bounces acquisitions holdtime-min holdtime-max holdtime-total holdtime-avg
		04-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
		05
		06 &mm->mmap_sem-W: 233 538 18446744073708 22924.27 607243.51 1342 45806 1.71 8595.89 1180582.34
		07 &mm->mmap_sem-R: 205 587 18446744073708 28403.36 731975.00 1940 412426 0.58 187825.45 6307502.88
		06 &mm->mmap_sem-W: 46 84 0.26 939.10 16371.53 194.90 47291 2922365 0.16 2220301.69 17464026916.32 5975.99
		07 &mm->mmap_sem-R: 37 100 1.31 299502.61 325629.52 3256.30 212344 34316685 0.10 7744.91 95016910.20 2.77
		08 ---------------
		09 &mm->mmap_sem 487 [<ffffffff8053491f>] do_page_fault+0x466/0x928
		10 &mm->mmap_sem 179 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
		11 &mm->mmap_sem 279 [<ffffffff80210a57>] sys_mmap+0x75/0xce
		12 &mm->mmap_sem 76 [<ffffffff802a490b>] sys_munmap+0x32/0x59
		09 &mm->mmap_sem 1 [<ffffffff811502a7>] khugepaged_scan_mm_slot+0x57/0x280
		19 &mm->mmap_sem 96 [<ffffffff815351c4>] __do_page_fault+0x1d4/0x510
		11 &mm->mmap_sem 34 [<ffffffff81113d77>] vm_mmap_pgoff+0x87/0xd0
		12 &mm->mmap_sem 17 [<ffffffff81127e71>] vm_munmap+0x41/0x80
		13 ---------------
		14 &mm->mmap_sem 270 [<ffffffff80210a57>] sys_mmap+0x75/0xce
		15 &mm->mmap_sem 431 [<ffffffff8053491f>] do_page_fault+0x466/0x928
		16 &mm->mmap_sem 138 [<ffffffff802a490b>] sys_munmap+0x32/0x59
		17 &mm->mmap_sem 145 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
		14 &mm->mmap_sem 1 [<ffffffff81046fda>] dup_mmap+0x2a/0x3f0
		15 &mm->mmap_sem 60 [<ffffffff81129e29>] SyS_mprotect+0xe9/0x250
		16 &mm->mmap_sem 41 [<ffffffff815351c4>] __do_page_fault+0x1d4/0x510
		17 &mm->mmap_sem 68 [<ffffffff81113d77>] vm_mmap_pgoff+0x87/0xd0
		18
		19 ...............................................................................................................................................................................................
		19.............................................................................................................................................................................................................................
		20
		21 dcache_lock: 621 623 0.52 118.26 1053.02 6745 91930 0.29 316.29 118423.41
		22 -----------
		23 dcache_lock 179 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
		24 dcache_lock 113 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
		25 dcache_lock 99 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
		26 dcache_lock 104 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
		27 -----------
		28 dcache_lock 192 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
		29 dcache_lock 98 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
		30 dcache_lock 72 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
		31 dcache_lock 112 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
		21 unix_table_lock: 110 112 0.21 49.24 163.91 1.46 21094 66312 0.12 624.42 31589.81 0.48
		22 ---------------
		23 unix_table_lock 45 [<ffffffff8150ad8e>] unix_create1+0x16e/0x1b0
		24 unix_table_lock 47 [<ffffffff8150b111>] unix_release_sock+0x31/0x250
		25 unix_table_lock 15 [<ffffffff8150ca37>] unix_find_other+0x117/0x230
		26 unix_table_lock 5 [<ffffffff8150a09f>] unix_autobind+0x11f/0x1b0
		27 ---------------
		28 unix_table_lock 39 [<ffffffff8150b111>] unix_release_sock+0x31/0x250
		29 unix_table_lock 49 [<ffffffff8150ad8e>] unix_create1+0x16e/0x1b0
		30 unix_table_lock 20 [<ffffffff8150ca37>] unix_find_other+0x117/0x230
		31 unix_table_lock 4 [<ffffffff8150a09f>] unix_autobind+0x11f/0x1b0


		This excerpt shows the first two lock class statistics. Line 01 shows the
		output version - each time the format changes this will be updated. Line 02-04
		@@ -131,9 +130,9 @@ The integer part of the time values is in us.

		Dealing with nested locks, subclasses may appear:

		32...............................................................................................................................................................................................
		32...........................................................................................................................................................................................................................
		33
		34 &rq->lock: 13128 13128 0.43 190.53 103881.26 97454 3453404 0.00 401.11 13224683.11
		34 &rq->lock: 13128 13128 0.43 190.53 103881.26 7.91 97454 3453404 0.00 401.11 13224683.11 3.82
		35 ---------
		36 &rq->lock 645 [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
		37 &rq->lock 297 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
		@@ -145,9 +144,9 @@ Dealing with nested locks, subclasses may appear:
		43 &rq->lock 4715 [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
		44 &rq->lock 893 [<ffffffff81340524>] schedule+0x157/0x7b8
		45
		46...............................................................................................................................................................................................
		46...........................................................................................................................................................................................................................
		47
		48 &rq->lock/1: 11526 11488 0.33 388.73 136294.31 21461 38404 0.00 37.93 109388.53
		48 &rq->lock/1: 1526 11488 0.33 388.73 136294.31 11.86 21461 38404 0.00 37.93 109388.53 2.84
		49 -----------
		50 &rq->lock/1 11526 [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
		51 -----------
		@@ -163,16 +162,16 @@ double_rq_lock actually acquires a nested lock of two spinlocks.
		View the top contending locks:

		# grep : /proc/lock_stat \| head
		&inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60
		&inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38
		dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24
		&inode->i_mutex: 161 286 18446744073709 62882.54 1244614.55 3653 20598 18446744073709 62318.60 1693822.74
		&zone->lru_lock: 94 94 0.53 7.33 92.10 4366 32690 0.29 59.81 16350.06
		&inode->i_data.i_mmap_mutex: 79 79 0.40 3.77 53.03 11779 87755 0.28 116.93 29898.44
		&q->__queue_lock: 48 50 0.52 31.62 86.31 774 13131 0.17 113.08 12277.52
		&rq->rq_lock_key: 43 47 0.74 68.50 170.63 3706 33929 0.22 107.99 17460.62
		&rq->rq_lock_key#2: 39 46 0.75 6.68 49.03 2979 32292 0.17 125.17 17137.63
		tasklist_lock-W: 15 15 1.45 10.87 32.70 1201 7390 0.58 62.55 13648.47
		clockevents_lock: 2926159 2947636 0.15 46882.81 1784540466.34 605.41 3381345 3879161 0.00 2260.97 53178395.68 13.71
		tick_broadcast_lock: 346460 346717 0.18 2257.43 39364622.71 113.54 3642919 4242696 0.00 2263.79 49173646.60 11.59
		&mapping->i_mmap_mutex: 203896 203899 3.36 645530.05 31767507988.39 155800.21 3361776 8893984 0.17 2254.15 14110121.02 1.59
		&rq->lock: 135014 136909 0.18 606.09 842160.68 6.15 1540728 10436146 0.00 728.72 17606683.41 1.69
		&(&zone->lru_lock)->rlock: 93000 94934 0.16 59.18 188253.78 1.98 1199912 3809894 0.15 391.40 3559518.81 0.93
		tasklist_lock-W: 40667 41130 0.23 1189.42 428980.51 10.43 270278 510106 0.16 653.51 3939674.91 7.72
		tasklist_lock-R: 21298 21305 0.20 1310.05 215511.12 10.12 186204 241258 0.14 1162.33 1179779.23 4.89
		rcu_node_1: 47656 49022 0.16 635.41 193616.41 3.95 844888 1865423 0.00 764.26 1656226.96 0.89
		&(&dentry->d_lockref.lock)->rlock: 39791 40179 0.15 1302.08 88851.96 2.21 2790851 12527025 0.10 1910.75 3379714.27 0.27
		rcu_node_0: 29203 30064 0.16 786.55 1555573.00 51.74 88963 244254 0.00 398.87 428872.51 1.76

		Clear the statistics:

kernel/lockdep_proc.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -421,6 +421,7 @@ static void seq_lock_time(struct seq_file m, struct lock_time lt)
		seq_time(m, lt->min);
		seq_time(m, lt->max);
		seq_time(m, lt->total);
		seq_time(m, lt->nr ? do_div(lt->total, lt->nr) : 0);
		}

		static void seq_stats(struct seq_file m, struct lock_stat_data data)
		@@ -518,20 +519,20 @@ 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 + 10 * (14 + 1));
		seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
		seq_puts(m, "\n");
		}
		}

		static void seq_header(struct seq_file *m)
		{
		seq_printf(m, "lock_stat version 0.3\n");
		seq_puts(m, "lock_stat version 0.4\n");

		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",
		@@ -539,12 +540,14 @@ static void seq_header(struct seq_file *m)
		"waittime-min",
		"waittime-max",
		"waittime-total",
		"waittime-avg",
		"acq-bounces",
		"acquisitions",
		"holdtime-min",
		"holdtime-max",
		"holdtime-total");
		seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
		"holdtime-total",
		"holdtime-avg");
		seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
		seq_printf(m, "\n");
		}

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