diff options
| author |   Waiman Long <Waiman.Long@hpe.com> | 2016-05-31 12:53:47 -0400 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2016-08-10 14:16:02 +0200 |
| commit | 08be8f63c40c030b5cf95b4368e314e563a86301 (patch) | |
| tree | 79a14559d31108b7e9ad0c559c0070a39f146223 /kernel/locking/qspinlock_stat.h | |
| parent | locking/qspinlock: Improve readability (diff) | |
| download | wireguard-linux-08be8f63c40c030b5cf95b4368e314e563a86301.tar.xz wireguard-linux-08be8f63c40c030b5cf95b4368e314e563a86301.zip | |
locking/pvstat: Separate wait_again and spurious wakeup stats
Currently there are overlap in the pvqspinlock wait_again and
spurious_wakeup stat counters. Because of lock stealing, it is
no longer possible to accurately determine if spurious wakeup has
happened in the queue head. As they track both the queue node and
queue head status, it is also hard to tell how many of those comes
from the queue head and how many from the queue node.
This patch changes the accounting rules so that spurious wakeup is
only tracked in the queue node. The wait_again count, however, is
only tracked in the queue head when the vCPU failed to acquire the
lock after a vCPU kick. This should give a much better indication of
the wait-kick dynamics in the queue node and the queue head.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1464713631-1066-2-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/qspinlock_stat.h')
| -rw-r--r-- | kernel/locking/qspinlock_stat.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h index b9d031516254..eb0a599fcf58 100644 --- a/kernel/locking/qspinlock_stat.h +++ b/kernel/locking/qspinlock_stat.h @@ -24,8 +24,8 @@ * pv_latency_wake - average latency (ns) from vCPU kick to wakeup * pv_lock_slowpath - # of locking operations via the slowpath * pv_lock_stealing - # of lock stealing operations - * pv_spurious_wakeup - # of spurious wakeups - * pv_wait_again - # of vCPU wait's that happened after a vCPU kick + * pv_spurious_wakeup - # of spurious wakeups in non-head vCPUs + * pv_wait_again - # of wait's after a queue head vCPU kick * pv_wait_early - # of early vCPU wait's * pv_wait_head - # of vCPU wait's at the queue head * pv_wait_node - # of vCPU wait's at a non-head queue node |