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linux/kernel/locking/lock_events_list.h

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locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs The percpu event counts used by qspinlock code can be useful for other locking code as well. So a new set of lockevent_* counting APIs is introduced with the lock event names extracted out into the new lock_events_list.h header file for easier addition in the future. The existing qstat_inc() calls are replaced by either lockevent_inc() or lockevent_cond_inc() calls. The qstat_hop() call is renamed to lockevent_pv_hop(). The "reset_counters" debugfs file is also renamed to ".reset_counts". Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-8-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-04 20:43:16 +03:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Authors: Waiman Long <longman@redhat.com>
*/
#ifndef LOCK_EVENT
#define LOCK_EVENT(name) LOCKEVENT_ ## name,
#endif
#ifdef CONFIG_QUEUED_SPINLOCKS
#ifdef CONFIG_PARAVIRT_SPINLOCKS
/*
* Locking events for PV qspinlock.
*/
LOCK_EVENT(pv_hash_hops) /* Average # of hops per hashing operation */
LOCK_EVENT(pv_kick_unlock) /* # of vCPU kicks issued at unlock time */
LOCK_EVENT(pv_kick_wake) /* # of vCPU kicks for pv_latency_wake */
LOCK_EVENT(pv_latency_kick) /* Average latency (ns) of vCPU kick */
LOCK_EVENT(pv_latency_wake) /* Average latency (ns) of kick-to-wakeup */
LOCK_EVENT(pv_lock_stealing) /* # of lock stealing operations */
LOCK_EVENT(pv_spurious_wakeup) /* # of spurious wakeups in non-head vCPUs */
LOCK_EVENT(pv_wait_again) /* # of wait's after queue head vCPU kick */
LOCK_EVENT(pv_wait_early) /* # of early vCPU wait's */
LOCK_EVENT(pv_wait_head) /* # of vCPU wait's at the queue head */
LOCK_EVENT(pv_wait_node) /* # of vCPU wait's at non-head queue node */
#endif /* CONFIG_PARAVIRT_SPINLOCKS */
/*
* Locking events for qspinlock
*
* Subtracting lock_use_node[234] from lock_slowpath will give you
* lock_use_node1.
*/
LOCK_EVENT(lock_pending) /* # of locking ops via pending code */
LOCK_EVENT(lock_slowpath) /* # of locking ops via MCS lock queue */
LOCK_EVENT(lock_use_node2) /* # of locking ops that use 2nd percpu node */
LOCK_EVENT(lock_use_node3) /* # of locking ops that use 3rd percpu node */
LOCK_EVENT(lock_use_node4) /* # of locking ops that use 4th percpu node */
LOCK_EVENT(lock_no_node) /* # of locking ops w/o using percpu node */
#endif /* CONFIG_QUEUED_SPINLOCKS */
locking/rwsem: Enable lock event counting Add lock event counting calls so that we can track the number of lock events happening in the rwsem code. With CONFIG_LOCK_EVENT_COUNTS on and booting a 4-socket 112-thread x86-64 system, the rwsem counts after system bootup were as follows: rwsem_opt_fail=261 rwsem_opt_wlock=50636 rwsem_rlock=445 rwsem_rlock_fail=0 rwsem_rlock_fast=22 rwsem_rtrylock=810144 rwsem_sleep_reader=441 rwsem_sleep_writer=310 rwsem_wake_reader=355 rwsem_wake_writer=2335 rwsem_wlock=261 rwsem_wlock_fail=0 rwsem_wtrylock=20583 It can be seen that most of the lock acquisitions in the slowpath were write-locks in the optimistic spinning code path with no sleeping at all. For this system, over 97% of the locks are acquired via optimistic spinning. It illustrates the importance of optimistic spinning in improving the performance of rwsem. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-11-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-04 20:43:19 +03:00
/*
* Locking events for rwsem
*/
LOCK_EVENT(rwsem_sleep_reader) /* # of reader sleeps */
LOCK_EVENT(rwsem_sleep_writer) /* # of writer sleeps */
LOCK_EVENT(rwsem_wake_reader) /* # of reader wakeups */
LOCK_EVENT(rwsem_wake_writer) /* # of writer wakeups */
LOCK_EVENT(rwsem_opt_wlock) /* # of write locks opt-spin acquired */
LOCK_EVENT(rwsem_opt_fail) /* # of failed opt-spinnings */
LOCK_EVENT(rwsem_rlock) /* # of read locks acquired */
LOCK_EVENT(rwsem_rlock_fast) /* # of fast read locks acquired */
LOCK_EVENT(rwsem_rlock_fail) /* # of failed read lock acquisitions */
LOCK_EVENT(rwsem_wlock) /* # of write locks acquired */
LOCK_EVENT(rwsem_wlock_fail) /* # of failed write lock acquisitions */
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