From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- kernel/locking/qspinlock_stat.h | 142 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 kernel/locking/qspinlock_stat.h (limited to 'kernel/locking/qspinlock_stat.h') diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h new file mode 100644 index 000000000..e625bb410 --- /dev/null +++ b/kernel/locking/qspinlock_stat.h @@ -0,0 +1,142 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * + * Authors: Waiman Long + */ + +#include "lock_events.h" + +#ifdef CONFIG_LOCK_EVENT_COUNTS +#ifdef CONFIG_PARAVIRT_SPINLOCKS +/* + * Collect pvqspinlock locking event counts + */ +#include +#include +#include + +#define EVENT_COUNT(ev) lockevents[LOCKEVENT_ ## ev] + +/* + * PV specific per-cpu counter + */ +static DEFINE_PER_CPU(u64, pv_kick_time); + +/* + * Function to read and return the PV qspinlock counts. + * + * The following counters are handled specially: + * 1. pv_latency_kick + * Average kick latency (ns) = pv_latency_kick/pv_kick_unlock + * 2. pv_latency_wake + * Average wake latency (ns) = pv_latency_wake/pv_kick_wake + * 3. pv_hash_hops + * Average hops/hash = pv_hash_hops/pv_kick_unlock + */ +ssize_t lockevent_read(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + char buf[64]; + int cpu, id, len; + u64 sum = 0, kicks = 0; + + /* + * Get the counter ID stored in file->f_inode->i_private + */ + id = (long)file_inode(file)->i_private; + + if (id >= lockevent_num) + return -EBADF; + + for_each_possible_cpu(cpu) { + sum += per_cpu(lockevents[id], cpu); + /* + * Need to sum additional counters for some of them + */ + switch (id) { + + case LOCKEVENT_pv_latency_kick: + case LOCKEVENT_pv_hash_hops: + kicks += per_cpu(EVENT_COUNT(pv_kick_unlock), cpu); + break; + + case LOCKEVENT_pv_latency_wake: + kicks += per_cpu(EVENT_COUNT(pv_kick_wake), cpu); + break; + } + } + + if (id == LOCKEVENT_pv_hash_hops) { + u64 frac = 0; + + if (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", + sum, frac); + } else { + /* + * Round to the nearest ns + */ + if ((id == LOCKEVENT_pv_latency_kick) || + (id == LOCKEVENT_pv_latency_wake)) { + if (kicks) + sum = DIV_ROUND_CLOSEST_ULL(sum, kicks); + } + len = snprintf(buf, sizeof(buf) - 1, "%llu\n", sum); + } + + return simple_read_from_buffer(user_buf, count, ppos, buf, len); +} + +/* + * PV hash hop count + */ +static inline void lockevent_pv_hop(int hopcnt) +{ + this_cpu_add(EVENT_COUNT(pv_hash_hops), hopcnt); +} + +/* + * Replacement function for pv_kick() + */ +static inline void __pv_kick(int cpu) +{ + u64 start = sched_clock(); + + per_cpu(pv_kick_time, cpu) = start; + pv_kick(cpu); + this_cpu_add(EVENT_COUNT(pv_latency_kick), sched_clock() - start); +} + +/* + * Replacement function for pv_wait() + */ +static inline void __pv_wait(u8 *ptr, u8 val) +{ + u64 *pkick_time = this_cpu_ptr(&pv_kick_time); + + *pkick_time = 0; + pv_wait(ptr, val); + if (*pkick_time) { + this_cpu_add(EVENT_COUNT(pv_latency_wake), + sched_clock() - *pkick_time); + lockevent_inc(pv_kick_wake); + } +} + +#define pv_kick(c) __pv_kick(c) +#define pv_wait(p, v) __pv_wait(p, v) + +#endif /* CONFIG_PARAVIRT_SPINLOCKS */ + +#else /* CONFIG_LOCK_EVENT_COUNTS */ + +static inline void lockevent_pv_hop(int hopcnt) { } + +#endif /* CONFIG_LOCK_EVENT_COUNTS */ -- cgit v1.2.3