--- /dev/null
+/* 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 */
if (!(val & _Q_LOCKED_PENDING_MASK) &&
(cmpxchg_acquire(&lock->locked, 0, _Q_LOCKED_VAL) == 0)) {
- qstat_inc(qstat_pv_lock_stealing, true);
+ lockevent_inc(pv_lock_stealing);
return true;
}
if (!(val & _Q_TAIL_MASK) || (val & _Q_PENDING_MASK))
hopcnt++;
if (!cmpxchg(&he->lock, NULL, lock)) {
WRITE_ONCE(he->node, node);
- qstat_hop(hopcnt);
+ lockevent_pv_hop(hopcnt);
return &he->lock;
}
}
smp_store_mb(pn->state, vcpu_halted);
if (!READ_ONCE(node->locked)) {
- qstat_inc(qstat_pv_wait_node, true);
- qstat_inc(qstat_pv_wait_early, wait_early);
+ lockevent_inc(pv_wait_node);
+ lockevent_cond_inc(pv_wait_early, wait_early);
pv_wait(&pn->state, vcpu_halted);
}
* So it is better to spin for a while in the hope that the
* MCS lock will be released soon.
*/
- qstat_inc(qstat_pv_spurious_wakeup, !READ_ONCE(node->locked));
+ lockevent_cond_inc(pv_spurious_wakeup,
+ !READ_ONCE(node->locked));
}
/*
/*
* Tracking # of slowpath locking operations
*/
- qstat_inc(qstat_lock_slowpath, true);
+ lockevent_inc(lock_slowpath);
for (;; waitcnt++) {
/*
}
}
WRITE_ONCE(pn->state, vcpu_hashed);
- qstat_inc(qstat_pv_wait_head, true);
- qstat_inc(qstat_pv_wait_again, waitcnt);
+ lockevent_inc(pv_wait_head);
+ lockevent_cond_inc(pv_wait_again, waitcnt);
pv_wait(&lock->locked, _Q_SLOW_VAL);
/*
* vCPU is harmless other than the additional latency in completing
* the unlock.
*/
- qstat_inc(qstat_pv_kick_unlock, true);
+ lockevent_inc(pv_kick_unlock);
pv_kick(node->cpu);
}
* Subtracting lock_use_node[234] from lock_slowpath will give you
* lock_use_node1.
*
- * Writing to the "reset_counters" file will reset all the above counter
- * values.
+ * Writing to the special ".reset_counts" file will reset all the above
+ * counter values.
*
* These statistical counters are implemented as per-cpu variables which are
* summed and computed whenever the corresponding debugfs files are read. This
*
* There may be slight difference between pv_kick_wake and pv_kick_unlock.
*/
-enum qlock_stats {
- qstat_pv_hash_hops,
- qstat_pv_kick_unlock,
- qstat_pv_kick_wake,
- qstat_pv_latency_kick,
- qstat_pv_latency_wake,
- qstat_pv_lock_stealing,
- qstat_pv_spurious_wakeup,
- qstat_pv_wait_again,
- qstat_pv_wait_early,
- qstat_pv_wait_head,
- qstat_pv_wait_node,
- qstat_lock_pending,
- qstat_lock_slowpath,
- qstat_lock_use_node2,
- qstat_lock_use_node3,
- qstat_lock_use_node4,
- qstat_lock_no_node,
- qstat_num, /* Total number of statistical counters */
- qstat_reset_cnts = qstat_num,
-};
+#include "lock_events.h"
#ifdef CONFIG_QUEUED_LOCK_STAT
/*
#include <linux/sched/clock.h>
#include <linux/fs.h>
-static const char * const qstat_names[qstat_num + 1] = {
- [qstat_pv_hash_hops] = "pv_hash_hops",
- [qstat_pv_kick_unlock] = "pv_kick_unlock",
- [qstat_pv_kick_wake] = "pv_kick_wake",
- [qstat_pv_spurious_wakeup] = "pv_spurious_wakeup",
- [qstat_pv_latency_kick] = "pv_latency_kick",
- [qstat_pv_latency_wake] = "pv_latency_wake",
- [qstat_pv_lock_stealing] = "pv_lock_stealing",
- [qstat_pv_wait_again] = "pv_wait_again",
- [qstat_pv_wait_early] = "pv_wait_early",
- [qstat_pv_wait_head] = "pv_wait_head",
- [qstat_pv_wait_node] = "pv_wait_node",
- [qstat_lock_pending] = "lock_pending",
- [qstat_lock_slowpath] = "lock_slowpath",
- [qstat_lock_use_node2] = "lock_use_node2",
- [qstat_lock_use_node3] = "lock_use_node3",
- [qstat_lock_use_node4] = "lock_use_node4",
- [qstat_lock_no_node] = "lock_no_node",
- [qstat_reset_cnts] = "reset_counters",
+#define EVENT_COUNT(ev) lockevents[LOCKEVENT_ ## ev]
+
+#undef LOCK_EVENT
+#define LOCK_EVENT(name) [LOCKEVENT_ ## name] = #name,
+
+static const char * const lockevent_names[lockevent_num + 1] = {
+
+#include "lock_events_list.h"
+
+ [LOCKEVENT_reset_cnts] = ".reset_counts",
};
/*
* Per-cpu counters
*/
-static DEFINE_PER_CPU(unsigned long, qstats[qstat_num]);
+DEFINE_PER_CPU(unsigned long, lockevents[lockevent_num]);
static DEFINE_PER_CPU(u64, pv_kick_time);
/*
* Function to read and return the qlock statistical counter values
*
* The following counters are handled specially:
- * 1. qstat_pv_latency_kick
+ * 1. pv_latency_kick
* Average kick latency (ns) = pv_latency_kick/pv_kick_unlock
- * 2. qstat_pv_latency_wake
+ * 2. pv_latency_wake
* Average wake latency (ns) = pv_latency_wake/pv_kick_wake
- * 3. qstat_pv_hash_hops
+ * 3. pv_hash_hops
* Average hops/hash = pv_hash_hops/pv_kick_unlock
*/
-static ssize_t qstat_read(struct file *file, char __user *user_buf,
- size_t count, loff_t *ppos)
+static ssize_t lockevent_read(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
{
char buf[64];
- int cpu, counter, len;
- u64 stat = 0, kicks = 0;
+ int cpu, id, len;
+ u64 sum = 0, kicks = 0;
/*
* Get the counter ID stored in file->f_inode->i_private
*/
- counter = (long)file_inode(file)->i_private;
+ id = (long)file_inode(file)->i_private;
- if (counter >= qstat_num)
+ if (id >= lockevent_num)
return -EBADF;
for_each_possible_cpu(cpu) {
- stat += per_cpu(qstats[counter], cpu);
+ sum += per_cpu(lockevents[id], cpu);
/*
- * Need to sum additional counter for some of them
+ * Need to sum additional counters for some of them
*/
- switch (counter) {
+ switch (id) {
- case qstat_pv_latency_kick:
- case qstat_pv_hash_hops:
- kicks += per_cpu(qstats[qstat_pv_kick_unlock], cpu);
+ case LOCKEVENT_pv_latency_kick:
+ case LOCKEVENT_pv_hash_hops:
+ kicks += per_cpu(EVENT_COUNT(pv_kick_unlock), cpu);
break;
- case qstat_pv_latency_wake:
- kicks += per_cpu(qstats[qstat_pv_kick_wake], cpu);
+ case LOCKEVENT_pv_latency_wake:
+ kicks += per_cpu(EVENT_COUNT(pv_kick_wake), cpu);
break;
}
}
- if (counter == qstat_pv_hash_hops) {
+ if (id == LOCKEVENT_pv_hash_hops) {
u64 frac = 0;
if (kicks) {
- frac = 100ULL * do_div(stat, kicks);
+ frac = 100ULL * do_div(sum, kicks);
frac = DIV_ROUND_CLOSEST_ULL(frac, kicks);
}
/*
* Return a X.XX decimal number
*/
- len = snprintf(buf, sizeof(buf) - 1, "%llu.%02llu\n", stat, frac);
+ len = snprintf(buf, sizeof(buf) - 1, "%llu.%02llu\n",
+ sum, frac);
} else {
/*
* Round to the nearest ns
*/
- if ((counter == qstat_pv_latency_kick) ||
- (counter == qstat_pv_latency_wake)) {
+ if ((id == LOCKEVENT_pv_latency_kick) ||
+ (id == LOCKEVENT_pv_latency_wake)) {
if (kicks)
- stat = DIV_ROUND_CLOSEST_ULL(stat, kicks);
+ sum = DIV_ROUND_CLOSEST_ULL(sum, kicks);
}
- len = snprintf(buf, sizeof(buf) - 1, "%llu\n", stat);
+ len = snprintf(buf, sizeof(buf) - 1, "%llu\n", sum);
}
return simple_read_from_buffer(user_buf, count, ppos, buf, len);
/*
* Function to handle write request
*
- * When counter = reset_cnts, reset all the counter values.
- * Since the counter updates aren't atomic, the resetting is done twice
- * to make sure that the counters are very likely to be all cleared.
+ * When id = .reset_cnts, reset all the counter values.
*/
-static ssize_t qstat_write(struct file *file, const char __user *user_buf,
+static ssize_t lockevent_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
int cpu;
/*
* Get the counter ID stored in file->f_inode->i_private
*/
- if ((long)file_inode(file)->i_private != qstat_reset_cnts)
+ if ((long)file_inode(file)->i_private != LOCKEVENT_reset_cnts)
return count;
for_each_possible_cpu(cpu) {
int i;
- unsigned long *ptr = per_cpu_ptr(qstats, cpu);
+ unsigned long *ptr = per_cpu_ptr(lockevents, cpu);
- for (i = 0 ; i < qstat_num; i++)
+ for (i = 0 ; i < lockevent_num; i++)
WRITE_ONCE(ptr[i], 0);
}
return count;
/*
* Debugfs data structures
*/
-static const struct file_operations fops_qstat = {
- .read = qstat_read,
- .write = qstat_write,
+static const struct file_operations fops_lockevent = {
+ .read = lockevent_read,
+ .write = lockevent_write,
.llseek = default_llseek,
};
*/
static int __init init_qspinlock_stat(void)
{
- struct dentry *d_qstat = debugfs_create_dir("qlockstat", NULL);
+ struct dentry *d_counts = debugfs_create_dir("qlockstat", NULL);
int i;
- if (!d_qstat)
+ if (!d_counts)
goto out;
/*
* root is allowed to do the read/write to limit impact to system
* performance.
*/
- for (i = 0; i < qstat_num; i++)
- if (!debugfs_create_file(qstat_names[i], 0400, d_qstat,
- (void *)(long)i, &fops_qstat))
+ for (i = 0; i < lockevent_num; i++)
+ if (!debugfs_create_file(lockevent_names[i], 0400, d_counts,
+ (void *)(long)i, &fops_lockevent))
goto fail_undo;
- if (!debugfs_create_file(qstat_names[qstat_reset_cnts], 0200, d_qstat,
- (void *)(long)qstat_reset_cnts, &fops_qstat))
+ if (!debugfs_create_file(lockevent_names[LOCKEVENT_reset_cnts], 0200,
+ d_counts, (void *)(long)LOCKEVENT_reset_cnts,
+ &fops_lockevent))
goto fail_undo;
return 0;
fail_undo:
- debugfs_remove_recursive(d_qstat);
+ debugfs_remove_recursive(d_counts);
out:
pr_warn("Could not create 'qlockstat' debugfs entries\n");
return -ENOMEM;
}
fs_initcall(init_qspinlock_stat);
-/*
- * Increment the PV qspinlock statistical counters
- */
-static inline void qstat_inc(enum qlock_stats stat, bool cond)
-{
- if (cond)
- this_cpu_inc(qstats[stat]);
-}
-
/*
* PV hash hop count
*/
-static inline void qstat_hop(int hopcnt)
+static inline void lockevent_pv_hop(int hopcnt)
{
- this_cpu_add(qstats[qstat_pv_hash_hops], hopcnt);
+ this_cpu_add(EVENT_COUNT(pv_hash_hops), hopcnt);
}
/*
per_cpu(pv_kick_time, cpu) = start;
pv_kick(cpu);
- this_cpu_add(qstats[qstat_pv_latency_kick], sched_clock() - start);
+ this_cpu_add(EVENT_COUNT(pv_latency_kick), sched_clock() - start);
}
/*
*pkick_time = 0;
pv_wait(ptr, val);
if (*pkick_time) {
- this_cpu_add(qstats[qstat_pv_latency_wake],
+ this_cpu_add(EVENT_COUNT(pv_latency_wake),
sched_clock() - *pkick_time);
- qstat_inc(qstat_pv_kick_wake, true);
+ lockevent_inc(pv_kick_wake);
}
}
#else /* CONFIG_QUEUED_LOCK_STAT */
-static inline void qstat_inc(enum qlock_stats stat, bool cond) { }
-static inline void qstat_hop(int hopcnt) { }
+static inline void lockevent_pv_hop(int hopcnt) { }
#endif /* CONFIG_QUEUED_LOCK_STAT */