From: Waiman Long Date: Thu, 10 Dec 2015 20:17:45 +0000 (-0500) Subject: locking/pvqspinlock: Enable slowpath locking count tracking X-Git-Tag: v4.14-rc1~3686^2~12 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=32d62510f949d3c8e83b9b3b844a84446611661b;p=platform%2Fkernel%2Flinux-rpi.git locking/pvqspinlock: Enable slowpath locking count tracking This patch enables the tracking of the number of slowpath locking operations performed. This can be used to compare against the number of lock stealing operations to see what percentage of locks are stolen versus acquired via the regular slowpath. Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Douglas Hatch Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Scott J Norton Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1449778666-13593-2-git-send-email-Waiman.Long@hpe.com Signed-off-by: Ingo Molnar --- diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 78f04a2..21ede57 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -400,6 +400,11 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node) if (READ_ONCE(pn->state) == vcpu_hashed) lp = (struct qspinlock **)1; + /* + * Tracking # of slowpath locking operations + */ + qstat_inc(qstat_pv_lock_slowpath, true); + for (;; waitcnt++) { /* * Set correct vCPU state to be used by queue node wait-early diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h index 869988d..eb2a2c9 100644 --- a/kernel/locking/qspinlock_stat.h +++ b/kernel/locking/qspinlock_stat.h @@ -22,6 +22,7 @@ * pv_kick_wake - # of vCPU kicks used for computing pv_latency_wake * pv_latency_kick - average latency (ns) of vCPU kick operation * 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 @@ -45,6 +46,7 @@ enum qlock_stats { qstat_pv_kick_wake, qstat_pv_latency_kick, qstat_pv_latency_wake, + qstat_pv_lock_slowpath, qstat_pv_lock_stealing, qstat_pv_spurious_wakeup, qstat_pv_wait_again, @@ -70,6 +72,7 @@ static const char * const qstat_names[qstat_num + 1] = { [qstat_pv_spurious_wakeup] = "pv_spurious_wakeup", [qstat_pv_latency_kick] = "pv_latency_kick", [qstat_pv_latency_wake] = "pv_latency_wake", + [qstat_pv_lock_slowpath] = "pv_lock_slowpath", [qstat_pv_lock_stealing] = "pv_lock_stealing", [qstat_pv_wait_again] = "pv_wait_again", [qstat_pv_wait_early] = "pv_wait_early",