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Diffstat (limited to 'include/linux/time_stats.h')
| -rw-r--r-- | include/linux/time_stats.h | 167 |
1 files changed, 0 insertions, 167 deletions
diff --git a/include/linux/time_stats.h b/include/linux/time_stats.h deleted file mode 100644 index 6df2b34a..00000000 --- a/include/linux/time_stats.h +++ /dev/null @@ -1,167 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * time_stats - collect statistics on events that have a duration, with nicely - * formatted textual output on demand - * - * - percpu buffering of event collection: cheap enough to shotgun - * everywhere without worrying about overhead - * - * tracks: - * - number of events - * - maximum event duration ever seen - * - sum of all event durations - * - average event duration, standard and weighted - * - standard deviation of event durations, standard and weighted - * and analagous statistics for the frequency of events - * - * We provide both mean and weighted mean (exponentially weighted), and standard - * deviation and weighted standard deviation, to give an efficient-to-compute - * view of current behaviour versus. average behaviour - "did this event source - * just become wonky, or is this typical?". - * - * Particularly useful for tracking down latency issues. - */ -#ifndef _LINUX_TIME_STATS_H -#define _LINUX_TIME_STATS_H - -#include <linux/mean_and_variance.h> -#include <linux/sched/clock.h> -#include <linux/spinlock_types.h> -#include <linux/string.h> - -struct time_unit { - const char *name; - u64 nsecs; -}; - -/* - * given a nanosecond value, pick the preferred time units for printing: - */ -const struct time_unit *pick_time_units(u64 ns); - -/* - * quantiles - do not use: - * - * Only enabled if time_stats->quantiles_enabled has been manually set - don't - * use in new code. - */ - -#define NR_QUANTILES 15 -#define QUANTILE_IDX(i) inorder_to_eytzinger0(i, NR_QUANTILES) -#define QUANTILE_FIRST eytzinger0_first(NR_QUANTILES) -#define QUANTILE_LAST eytzinger0_last(NR_QUANTILES) - -struct quantiles { - struct quantile_entry { - u64 m; - u64 step; - } entries[NR_QUANTILES]; -}; - -struct time_stat_buffer { - unsigned nr; - struct time_stat_buffer_entry { - u64 start; - u64 end; - } entries[31]; -}; - -struct time_stats { - spinlock_t lock; - bool have_quantiles; - /* all fields are in nanoseconds */ - u64 min_duration; - u64 max_duration; - u64 total_duration; - u64 max_freq; - u64 min_freq; - u64 last_event; - u64 last_event_start; - - struct mean_and_variance duration_stats; - struct mean_and_variance freq_stats; - -/* default weight for weighted mean and variance calculations */ -#define TIME_STATS_MV_WEIGHT 8 - - struct mean_and_variance_weighted duration_stats_weighted; - struct mean_and_variance_weighted freq_stats_weighted; - struct time_stat_buffer __percpu *buffer; - - u64 start_time; -}; - -struct time_stats_quantiles { - struct time_stats stats; - struct quantiles quantiles; -}; - -static inline struct quantiles *time_stats_to_quantiles(struct time_stats *stats) -{ - return stats->have_quantiles - ? &container_of(stats, struct time_stats_quantiles, stats)->quantiles - : NULL; -} - -void __time_stats_clear_buffer(struct time_stats *, struct time_stat_buffer *); -void __time_stats_update(struct time_stats *stats, u64, u64); - -/** - * time_stats_update - collect a new event being tracked - * - * @stats - time_stats to update - * @start - start time of event, recorded with local_clock() - * - * The end duration of the event will be the current time - */ -static inline void time_stats_update(struct time_stats *stats, u64 start) -{ - __time_stats_update(stats, start, local_clock()); -} - -/** - * track_event_change - track state change events - * - * @stats - time_stats to update - * @v - new state, true or false - * - * Use this when tracking time stats for state changes, i.e. resource X becoming - * blocked/unblocked. - */ -static inline bool track_event_change(struct time_stats *stats, bool v) -{ - if (v != !!stats->last_event_start) { - if (!v) { - time_stats_update(stats, stats->last_event_start); - stats->last_event_start = 0; - } else { - stats->last_event_start = local_clock() ?: 1; - return true; - } - } - - return false; -} - -#define TIME_STATS_PRINT_NO_ZEROES (1U << 0) /* print nothing if zero count */ -struct seq_buf; -void time_stats_to_seq_buf(struct seq_buf *, struct time_stats *, - const char *epoch_name, unsigned int flags); -void time_stats_to_json(struct seq_buf *, struct time_stats *, - const char *epoch_name, unsigned int flags); - -void time_stats_exit(struct time_stats *); -void time_stats_init(struct time_stats *); - -static inline void time_stats_quantiles_exit(struct time_stats_quantiles *statq) -{ - time_stats_exit(&statq->stats); -} -static inline void time_stats_quantiles_init(struct time_stats_quantiles *statq) -{ - time_stats_init(&statq->stats); - statq->stats.have_quantiles = true; - memset(&statq->quantiles, 0, sizeof(statq->quantiles)); -} - -#endif /* _LINUX_TIME_STATS_H */ |