diff options
| -rw-r--r-- | Documentation/lockstat.txt | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt index 9c0a80d17a23..cef00d42ed5b 100644 --- a/Documentation/lockstat.txt +++ b/Documentation/lockstat.txt @@ -12,8 +12,9 @@ Because things like lock contention can severely impact performance. - HOW Lockdep already has hooks in the lock functions and maps lock instances to -lock classes. We build on that. The graph below shows the relation between -the lock functions and the various hooks therein. +lock classes. We build on that (see Documentation/lockdep-design.txt). +The graph below shows the relation between the lock functions and the various +hooks therein. __acquire | @@ -128,6 +129,37 @@ points are the points we're contending with. The integer part of the time values is in us. +Dealing with nested locks, subclasses may appear: + +32............................................................................................................................................................................................... +33 +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 +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 +45 +46............................................................................................................................................................................................... +47 +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 +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 + +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, +double_rq_lock actually acquires a nested lock of two spinlocks. + View the top contending locks: # grep : /proc/lock_stat | head |