summaryrefslogtreecommitdiff
path: root/Documentation/lockstat.txt
diff options
context:
space:
mode:
authorScott Wood <scottwood@freescale.com>2014-04-07 23:49:35 (GMT)
committerScott Wood <scottwood@freescale.com>2014-04-07 23:49:35 (GMT)
commit62b8c978ee6b8d135d9e7953221de58000dba986 (patch)
tree683b04b2e627f6710c22c151b23c8cc9a165315e /Documentation/lockstat.txt
parent78fd82238d0e5716578c326404184a27ba67fd6e (diff)
downloadlinux-fsl-qoriq-62b8c978ee6b8d135d9e7953221de58000dba986.tar.xz
Rewind v3.13-rc3+ (78fd82238d0e5716) to v3.12
Diffstat (limited to 'Documentation/lockstat.txt')
-rw-r--r--Documentation/lockstat.txt123
1 files changed, 62 insertions, 61 deletions
diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt
index 72d0106..dd2f7b2 100644
--- a/Documentation/lockstat.txt
+++ b/Documentation/lockstat.txt
@@ -46,14 +46,16 @@ With these hooks we provide the following statistics:
contentions - number of lock acquisitions that had to wait
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
+ total - total time we spend 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
- avg - average time this lock was held
+ 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
These numbers are gathered per lock class, per read/write state (when
applicable).
@@ -82,38 +84,37 @@ Look at the current lock statistics:
# less /proc/lock_stat
-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-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+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 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
05
-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 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 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
+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
+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
+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
18
-19.............................................................................................................................................................................................................................
+19 ...............................................................................................................................................................................................
20
-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
-
+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
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
@@ -130,30 +131,30 @@ 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 7.91 97454 3453404 0.00 401.11 13224683.11 3.82
+34 &rq->lock: 13128 13128 0.43 190.53 103881.26 97454 3453404 0.00 401.11 13224683.11
35 ---------
-36 &rq->lock 645 [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
-37 &rq->lock 297 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
-38 &rq->lock 360 [<ffffffff8103c4c5>] select_task_rq_fair+0x1f0/0x74a
-39 &rq->lock 428 [<ffffffff81045f98>] scheduler_tick+0x46/0x1fb
+36 &rq->lock 645 [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
+37 &rq->lock 297 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
+38 &rq->lock 360 [<ffffffff8103c4c5>] select_task_rq_fair+0x1f0/0x74a
+39 &rq->lock 428 [<ffffffff81045f98>] scheduler_tick+0x46/0x1fb
40 ---------
-41 &rq->lock 77 [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
-42 &rq->lock 174 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
-43 &rq->lock 4715 [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
-44 &rq->lock 893 [<ffffffff81340524>] schedule+0x157/0x7b8
+41 &rq->lock 77 [<ffffffff8103bfc4>] task_rq_lock+0x43/0x75
+42 &rq->lock 174 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
+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: 1526 11488 0.33 388.73 136294.31 11.86 21461 38404 0.00 37.93 109388.53 2.84
+48 &rq->lock/1: 11526 11488 0.33 388.73 136294.31 21461 38404 0.00 37.93 109388.53
49 -----------
-50 &rq->lock/1 11526 [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
+50 &rq->lock/1 11526 [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
51 -----------
-52 &rq->lock/1 5645 [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
-53 &rq->lock/1 1224 [<ffffffff81340524>] schedule+0x157/0x7b8
-54 &rq->lock/1 4336 [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
-55 &rq->lock/1 181 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
+52 &rq->lock/1 5645 [<ffffffff8103ed4b>] double_rq_lock+0x42/0x54
+53 &rq->lock/1 1224 [<ffffffff81340524>] schedule+0x157/0x7b8
+54 &rq->lock/1 4336 [<ffffffff8103ed58>] double_rq_lock+0x4f/0x54
+55 &rq->lock/1 181 [<ffffffff8104ba65>] try_to_wake_up+0x127/0x25a
Line 48 shows statistics for the second subclass (/1) of &rq->lock class
(subclass starts from 0), since in this case, as line 50 suggests,
@@ -162,16 +163,16 @@ double_rq_lock actually acquires a nested lock of two spinlocks.
View the top contending locks:
# grep : /proc/lock_stat | head
- 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
+ &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
Clear the statistics: