diff options
Diffstat (limited to 'fs/bcachefs/time_stats.c')
| -rw-r--r-- | fs/bcachefs/time_stats.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/fs/bcachefs/time_stats.c b/fs/bcachefs/time_stats.c new file mode 100644 index 000000000000..4508e9dcbee2 --- /dev/null +++ b/fs/bcachefs/time_stats.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/preempt.h> +#include <linux/time.h> +#include <linux/spinlock.h> + +#include "eytzinger.h" +#include "time_stats.h" + +static const struct time_unit time_units[] = { + { "ns", 1 }, + { "us", NSEC_PER_USEC }, + { "ms", NSEC_PER_MSEC }, + { "s", NSEC_PER_SEC }, + { "m", (u64) NSEC_PER_SEC * 60}, + { "h", (u64) NSEC_PER_SEC * 3600}, + { "d", (u64) NSEC_PER_SEC * 3600 * 24}, + { "w", (u64) NSEC_PER_SEC * 3600 * 24 * 7}, + { "y", (u64) NSEC_PER_SEC * ((3600 * 24 * 7 * 365) + (3600 * (24 / 4) * 7))}, /* 365.25d */ + { "eon", U64_MAX }, +}; + +const struct time_unit *bch2_pick_time_units(u64 ns) +{ + const struct time_unit *u; + + for (u = time_units; + u + 1 < time_units + ARRAY_SIZE(time_units) && + ns >= u[1].nsecs << 1; + u++) + ; + + return u; +} + +static void quantiles_update(struct quantiles *q, u64 v) +{ + unsigned i = 0; + + while (i < ARRAY_SIZE(q->entries)) { + struct quantile_entry *e = q->entries + i; + + if (unlikely(!e->step)) { + e->m = v; + e->step = max_t(unsigned, v / 2, 1024); + } else if (e->m > v) { + e->m = e->m >= e->step + ? e->m - e->step + : 0; + } else if (e->m < v) { + e->m = e->m + e->step > e->m + ? e->m + e->step + : U32_MAX; + } + + if ((e->m > v ? e->m - v : v - e->m) < e->step) + e->step = max_t(unsigned, e->step / 2, 1); + + if (v >= e->m) + break; + + i = eytzinger0_child(i, v > e->m); + } +} + +static inline void time_stats_update_one(struct bch2_time_stats *stats, + u64 start, u64 end) +{ + u64 duration, freq; + bool initted = stats->last_event != 0; + + if (time_after64(end, start)) { + struct quantiles *quantiles = time_stats_to_quantiles(stats); + + duration = end - start; + mean_and_variance_update(&stats->duration_stats, duration); + mean_and_variance_weighted_update(&stats->duration_stats_weighted, + duration, initted, TIME_STATS_MV_WEIGHT); + stats->max_duration = max(stats->max_duration, duration); + stats->min_duration = min(stats->min_duration, duration); + stats->total_duration += duration; + + if (quantiles) + quantiles_update(quantiles, duration); + } + + if (stats->last_event && time_after64(end, stats->last_event)) { + freq = end - stats->last_event; + mean_and_variance_update(&stats->freq_stats, freq); + mean_and_variance_weighted_update(&stats->freq_stats_weighted, + freq, initted, TIME_STATS_MV_WEIGHT); + stats->max_freq = max(stats->max_freq, freq); + stats->min_freq = min(stats->min_freq, freq); + } + + stats->last_event = end; +} + +void __bch2_time_stats_clear_buffer(struct bch2_time_stats *stats, + struct time_stat_buffer *b) +{ + for (struct time_stat_buffer_entry *i = b->entries; + i < b->entries + ARRAY_SIZE(b->entries); + i++) + time_stats_update_one(stats, i->start, i->end); + b->nr = 0; +} + +static noinline void time_stats_clear_buffer(struct bch2_time_stats *stats, + struct time_stat_buffer *b) +{ + unsigned long flags; + + spin_lock_irqsave(&stats->lock, flags); + __bch2_time_stats_clear_buffer(stats, b); + spin_unlock_irqrestore(&stats->lock, flags); +} + +void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end) +{ + unsigned long flags; + + if (!stats->buffer) { + spin_lock_irqsave(&stats->lock, flags); + time_stats_update_one(stats, start, end); + + if (mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT) < 32 && + stats->duration_stats.n > 1024) + stats->buffer = + alloc_percpu_gfp(struct time_stat_buffer, + GFP_ATOMIC); + spin_unlock_irqrestore(&stats->lock, flags); + } else { + struct time_stat_buffer *b; + + preempt_disable(); + b = this_cpu_ptr(stats->buffer); + + BUG_ON(b->nr >= ARRAY_SIZE(b->entries)); + b->entries[b->nr++] = (struct time_stat_buffer_entry) { + .start = start, + .end = end + }; + + if (unlikely(b->nr == ARRAY_SIZE(b->entries))) + time_stats_clear_buffer(stats, b); + preempt_enable(); + } +} + +void bch2_time_stats_exit(struct bch2_time_stats *stats) +{ + free_percpu(stats->buffer); +} + +void bch2_time_stats_init(struct bch2_time_stats *stats) +{ + memset(stats, 0, sizeof(*stats)); + stats->min_duration = U64_MAX; + stats->min_freq = U64_MAX; + spin_lock_init(&stats->lock); +} |