^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* SPDX-License-Identifier: GPL-2.0-or-later */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * Authors: Waiman Long <longman@redhat.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include "lock_events.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #ifdef CONFIG_LOCK_EVENT_COUNTS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #ifdef CONFIG_PARAVIRT_SPINLOCKS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * Collect pvqspinlock locking event counts
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/sched/clock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #define EVENT_COUNT(ev) lockevents[LOCKEVENT_ ## ev]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * PV specific per-cpu counter
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) static DEFINE_PER_CPU(u64, pv_kick_time);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * Function to read and return the PV qspinlock counts.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * The following counters are handled specially:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * 1. pv_latency_kick
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) * Average kick latency (ns) = pv_latency_kick/pv_kick_unlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * 2. pv_latency_wake
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * Average wake latency (ns) = pv_latency_wake/pv_kick_wake
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * 3. pv_hash_hops
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * Average hops/hash = pv_hash_hops/pv_kick_unlock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) ssize_t lockevent_read(struct file *file, char __user *user_buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) size_t count, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) char buf[64];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) int cpu, id, len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) u64 sum = 0, kicks = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * Get the counter ID stored in file->f_inode->i_private
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) id = (long)file_inode(file)->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) if (id >= lockevent_num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) return -EBADF;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) for_each_possible_cpu(cpu) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) sum += per_cpu(lockevents[id], cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * Need to sum additional counters for some of them
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) switch (id) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) case LOCKEVENT_pv_latency_kick:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) case LOCKEVENT_pv_hash_hops:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) kicks += per_cpu(EVENT_COUNT(pv_kick_unlock), cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) case LOCKEVENT_pv_latency_wake:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) kicks += per_cpu(EVENT_COUNT(pv_kick_wake), cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) if (id == LOCKEVENT_pv_hash_hops) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) u64 frac = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) if (kicks) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) frac = 100ULL * do_div(sum, kicks);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) frac = DIV_ROUND_CLOSEST_ULL(frac, kicks);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) * Return a X.XX decimal number
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) len = snprintf(buf, sizeof(buf) - 1, "%llu.%02llu\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) sum, frac);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) * Round to the nearest ns
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) if ((id == LOCKEVENT_pv_latency_kick) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) (id == LOCKEVENT_pv_latency_wake)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) if (kicks)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) sum = DIV_ROUND_CLOSEST_ULL(sum, kicks);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) len = snprintf(buf, sizeof(buf) - 1, "%llu\n", sum);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) return simple_read_from_buffer(user_buf, count, ppos, buf, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) * PV hash hop count
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) static inline void lockevent_pv_hop(int hopcnt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) this_cpu_add(EVENT_COUNT(pv_hash_hops), hopcnt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) * Replacement function for pv_kick()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) static inline void __pv_kick(int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) u64 start = sched_clock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) per_cpu(pv_kick_time, cpu) = start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) pv_kick(cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) this_cpu_add(EVENT_COUNT(pv_latency_kick), sched_clock() - start);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) * Replacement function for pv_wait()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) static inline void __pv_wait(u8 *ptr, u8 val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) u64 *pkick_time = this_cpu_ptr(&pv_kick_time);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) *pkick_time = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) pv_wait(ptr, val);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) if (*pkick_time) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) this_cpu_add(EVENT_COUNT(pv_latency_wake),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) sched_clock() - *pkick_time);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) lockevent_inc(pv_kick_wake);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) #define pv_kick(c) __pv_kick(c)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) #define pv_wait(p, v) __pv_wait(p, v)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) #endif /* CONFIG_PARAVIRT_SPINLOCKS */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) #else /* CONFIG_LOCK_EVENT_COUNTS */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) static inline void lockevent_pv_hop(int hopcnt) { }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) #endif /* CONFIG_LOCK_EVENT_COUNTS */
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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