--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/eytzinger.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/preempt.h>
+#include <linux/time.h>
+#include <linux/time_stats.h>
+#include <linux/spinlock.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 *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;
+}
+EXPORT_SYMBOL_GPL(pick_time_units);
+
+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 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 __time_stats_clear_buffer(struct 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;
+}
+EXPORT_SYMBOL_GPL(__time_stats_clear_buffer);
+
+static noinline void time_stats_clear_buffer(struct time_stats *stats,
+ struct time_stat_buffer *b)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&stats->lock, flags);
+ __time_stats_clear_buffer(stats, b);
+ spin_unlock_irqrestore(&stats->lock, flags);
+}
+
+void __time_stats_update(struct 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();
+ }
+}
+EXPORT_SYMBOL_GPL(__time_stats_update);
+
+#include <linux/seq_buf.h>
+
+static void seq_buf_time_units_aligned(struct seq_buf *out, u64 ns)
+{
+ const struct time_unit *u = pick_time_units(ns);
+
+ seq_buf_printf(out, "%8llu %s", div64_u64(ns, u->nsecs), u->name);
+}
+
+static inline u64 time_stats_lifetime(const struct time_stats *stats)
+{
+ return local_clock() - stats->start_time;
+}
+
+void time_stats_to_seq_buf(struct seq_buf *out, struct time_stats *stats,
+ const char *epoch_name, unsigned int flags)
+{
+ struct quantiles *quantiles = time_stats_to_quantiles(stats);
+ s64 f_mean = 0, d_mean = 0;
+ u64 f_stddev = 0, d_stddev = 0;
+ u64 lifetime = time_stats_lifetime(stats);
+
+ if (stats->buffer) {
+ int cpu;
+
+ spin_lock_irq(&stats->lock);
+ for_each_possible_cpu(cpu)
+ __time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));
+ spin_unlock_irq(&stats->lock);
+ }
+
+ if (stats->freq_stats.n) {
+ /* avoid divide by zero */
+ f_mean = mean_and_variance_get_mean(stats->freq_stats);
+ f_stddev = mean_and_variance_get_stddev(stats->freq_stats);
+ d_mean = mean_and_variance_get_mean(stats->duration_stats);
+ d_stddev = mean_and_variance_get_stddev(stats->duration_stats);
+ } else if (flags & TIME_STATS_PRINT_NO_ZEROES) {
+ /* unless we didn't want zeroes anyway */
+ return;
+ }
+
+ seq_buf_printf(out, "count: %llu\n", stats->duration_stats.n);
+ seq_buf_printf(out, "lifetime: ");
+ seq_buf_time_units_aligned(out, lifetime);
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " since %-12s recent\n", epoch_name);
+
+ seq_buf_printf(out, "duration of events\n");
+
+ seq_buf_printf(out, " min: ");
+ seq_buf_time_units_aligned(out, stats->min_duration);
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " max: ");
+ seq_buf_time_units_aligned(out, stats->max_duration);
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " total: ");
+ seq_buf_time_units_aligned(out, stats->total_duration);
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " mean: ");
+ seq_buf_time_units_aligned(out, d_mean);
+ seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT));
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " stddev: ");
+ seq_buf_time_units_aligned(out, d_stddev);
+ seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT));
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, "time between events\n");
+
+ seq_buf_printf(out, " min: ");
+ seq_buf_time_units_aligned(out, stats->min_freq);
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " max: ");
+ seq_buf_time_units_aligned(out, stats->max_freq);
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " mean: ");
+ seq_buf_time_units_aligned(out, f_mean);
+ seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT));
+ seq_buf_printf(out, "\n");
+
+ seq_buf_printf(out, " stddev: ");
+ seq_buf_time_units_aligned(out, f_stddev);
+ seq_buf_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT));
+ seq_buf_printf(out, "\n");
+
+ if (quantiles) {
+ int i = eytzinger0_first(NR_QUANTILES);
+ const struct time_unit *u =
+ pick_time_units(quantiles->entries[i].m);
+ u64 last_q = 0;
+
+ seq_buf_printf(out, "quantiles (%s):\t", u->name);
+ eytzinger0_for_each(i, NR_QUANTILES) {
+ bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1;
+
+ u64 q = max(quantiles->entries[i].m, last_q);
+ seq_buf_printf(out, "%llu ", div_u64(q, u->nsecs));
+ if (is_last)
+ seq_buf_printf(out, "\n");
+ last_q = q;
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(time_stats_to_seq_buf);
+
+void time_stats_to_json(struct seq_buf *out, struct time_stats *stats,
+ const char *epoch_name, unsigned int flags)
+{
+ struct quantiles *quantiles = time_stats_to_quantiles(stats);
+ s64 f_mean = 0, d_mean = 0;
+ u64 f_stddev = 0, d_stddev = 0;
+
+ if (stats->buffer) {
+ int cpu;
+
+ spin_lock_irq(&stats->lock);
+ for_each_possible_cpu(cpu)
+ __time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));
+ spin_unlock_irq(&stats->lock);
+ }
+
+ if (stats->freq_stats.n) {
+ /* avoid divide by zero */
+ f_mean = mean_and_variance_get_mean(stats->freq_stats);
+ f_stddev = mean_and_variance_get_stddev(stats->freq_stats);
+ d_mean = mean_and_variance_get_mean(stats->duration_stats);
+ d_stddev = mean_and_variance_get_stddev(stats->duration_stats);
+ } else if (flags & TIME_STATS_PRINT_NO_ZEROES) {
+ /* unless we didn't want zeroes anyway */
+ return;
+ }
+
+ seq_buf_printf(out, "{\n");
+ seq_buf_printf(out, " \"epoch\": \"%s\",\n", epoch_name);
+ seq_buf_printf(out, " \"count\": %llu,\n", stats->duration_stats.n);
+
+ seq_buf_printf(out, " \"duration_ns\": {\n");
+ seq_buf_printf(out, " \"min\": %llu,\n", stats->min_duration);
+ seq_buf_printf(out, " \"max\": %llu,\n", stats->max_duration);
+ seq_buf_printf(out, " \"total\": %llu,\n", stats->total_duration);
+ seq_buf_printf(out, " \"mean\": %llu,\n", d_mean);
+ seq_buf_printf(out, " \"stddev\": %llu\n", d_stddev);
+ seq_buf_printf(out, " },\n");
+
+ d_mean = mean_and_variance_weighted_get_mean(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT);
+ d_stddev = mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT);
+
+ seq_buf_printf(out, " \"duration_ewma_ns\": {\n");
+ seq_buf_printf(out, " \"mean\": %llu,\n", d_mean);
+ seq_buf_printf(out, " \"stddev\": %llu\n", d_stddev);
+ seq_buf_printf(out, " },\n");
+
+ seq_buf_printf(out, " \"frequency_ns\": {\n");
+ seq_buf_printf(out, " \"min\": %llu,\n", stats->min_freq);
+ seq_buf_printf(out, " \"max\": %llu,\n", stats->max_freq);
+ seq_buf_printf(out, " \"mean\": %llu,\n", f_mean);
+ seq_buf_printf(out, " \"stddev\": %llu\n", f_stddev);
+ seq_buf_printf(out, " },\n");
+
+ f_mean = mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT);
+ f_stddev = mean_and_variance_weighted_get_stddev(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT);
+
+ seq_buf_printf(out, " \"frequency_ewma_ns\": {\n");
+ seq_buf_printf(out, " \"mean\": %llu,\n", f_mean);
+ seq_buf_printf(out, " \"stddev\": %llu\n", f_stddev);
+
+ if (quantiles) {
+ u64 last_q = 0;
+
+ /* close frequency_ewma_ns but signal more items */
+ seq_buf_printf(out, " },\n");
+
+ seq_buf_printf(out, " \"quantiles_ns\": [\n");
+ eytzinger0_for_each(i, NR_QUANTILES) {
+ bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1;
+
+ u64 q = max(quantiles->entries[i].m, last_q);
+ seq_buf_printf(out, " %llu", q);
+ if (!is_last)
+ seq_buf_printf(out, ", ");
+ last_q = q;
+ }
+ seq_buf_printf(out, " ]\n");
+ } else {
+ /* close frequency_ewma_ns without dumping further */
+ seq_buf_printf(out, " }\n");
+ }
+
+ seq_buf_printf(out, "}\n");
+}
+EXPORT_SYMBOL_GPL(time_stats_to_json);
+
+void time_stats_exit(struct time_stats *stats)
+{
+ free_percpu(stats->buffer);
+}
+EXPORT_SYMBOL_GPL(time_stats_exit);
+
+void time_stats_init(struct time_stats *stats)
+{
+ memset(stats, 0, sizeof(*stats));
+ stats->min_duration = U64_MAX;
+ stats->min_freq = U64_MAX;
+ stats->start_time = local_clock();
+ spin_lock_init(&stats->lock);
+}
+EXPORT_SYMBOL_GPL(time_stats_init);
+
+MODULE_AUTHOR("Kent Overstreet");
+MODULE_LICENSE("GPL");
projects / bcachefs-tools-debian / blobdiff