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bcachefs: time_stats: split stats-with-quantiles into a separate structure

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Currently, struct time_stats has the optional ability to quantize the
information that it collects.  This is /probably/ useful for callers who
want to see quantized information, but it more than doubles the size of
the structure from 224 bytes to 464.  For users who don't care about
that (e.g. upcoming xfs patches) and want to avoid wasting 240 bytes per
counter, split the two into separate pieces.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Darrick J. Wong 2024-02-01 12:41:42 -08:00 committed by Kent Overstreet
parent 4b4f0876ab
commit 273960b8f3
7 changed files with 41 additions and 15 deletions
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2
fs/bcachefs/bcachefs.h
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@ -598,7 +598,7 @@ struct bch_dev {
/* The rest of this all shows up in sysfs */
atomic64_t cur_latency[2];
struct bch2_time_stats io_latency[2];
struct bch2_time_stats_quantiles io_latency[2];
#define CONGESTED_MAX 1024
atomic_t congested;

2
fs/bcachefs/io_write.c
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@ -88,7 +88,7 @@ void bch2_latency_acct(struct bch_dev *ca, u64 submit_time, int rw)
bch2_congested_acct(ca, io_latency, now, rw);
__bch2_time_stats_update(&ca->io_latency[rw], submit_time, now);
__bch2_time_stats_update(&ca->io_latency[rw].stats, submit_time, now);
}
#endif

8
fs/bcachefs/super.c
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@ -1189,8 +1189,8 @@ static void bch2_dev_free(struct bch_dev *ca)
bch2_dev_buckets_free(ca);
free_page((unsigned long) ca->sb_read_scratch);
bch2_time_stats_exit(&ca->io_latency[WRITE]);
bch2_time_stats_exit(&ca->io_latency[READ]);
bch2_time_stats_quantiles_exit(&ca->io_latency[WRITE]);
bch2_time_stats_quantiles_exit(&ca->io_latency[READ]);
percpu_ref_exit(&ca->io_ref);
percpu_ref_exit(&ca->ref);
@ -1281,8 +1281,8 @@ static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,
INIT_WORK(&ca->io_error_work, bch2_io_error_work);
bch2_time_stats_init(&ca->io_latency[READ]);
bch2_time_stats_init(&ca->io_latency[WRITE]);
bch2_time_stats_quantiles_init(&ca->io_latency[READ]);
bch2_time_stats_quantiles_init(&ca->io_latency[WRITE]);
ca->mi = bch2_mi_to_cpu(member);

4
fs/bcachefs/sysfs.c
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@ -930,10 +930,10 @@ SHOW(bch2_dev)
sysfs_print(io_latency_write, atomic64_read(&ca->cur_latency[WRITE]));
if (attr == &sysfs_io_latency_stats_read)
bch2_time_stats_to_text(out, &ca->io_latency[READ]);
bch2_time_stats_to_text(out, &ca->io_latency[READ].stats);
if (attr == &sysfs_io_latency_stats_write)
bch2_time_stats_to_text(out, &ca->io_latency[WRITE]);
bch2_time_stats_to_text(out, &ca->io_latency[WRITE].stats);
sysfs_printf(congested, "%u%%",
clamp(atomic_read(&ca->congested), 0, CONGESTED_MAX)

6
fs/bcachefs/time_stats.c
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@ -73,6 +73,8 @@ static inline void time_stats_update_one(struct bch2_time_stats *stats,
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,
@ -81,8 +83,8 @@ static inline void time_stats_update_one(struct bch2_time_stats *stats,
stats->min_duration = min(stats->min_duration, duration);
stats->total_duration += duration;
if (stats->quantiles_enabled)
quantiles_update(&stats->quantiles, duration);
if (quantiles)
quantiles_update(quantiles, duration);
}
if (stats->last_event && time_after64(end, stats->last_event)) {

27
fs/bcachefs/time_stats.h
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@ -26,6 +26,7 @@
#include <linux/sched/clock.h>
#include <linux/spinlock_types.h>
#include <linux/string.h>
#include "mean_and_variance.h"
@ -68,7 +69,7 @@ struct time_stat_buffer {
struct bch2_time_stats {
spinlock_t lock;
bool quantiles_enabled;
bool have_quantiles;
/* all fields are in nanoseconds */
u64 min_duration;
u64 max_duration;
@ -77,7 +78,6 @@ struct bch2_time_stats {
u64 min_freq;
u64 last_event;
u64 last_event_start;
struct quantiles quantiles;
struct mean_and_variance duration_stats;
struct mean_and_variance freq_stats;
@ -90,6 +90,18 @@ struct bch2_time_stats {
struct time_stat_buffer __percpu *buffer;
};
struct bch2_time_stats_quantiles {
struct bch2_time_stats stats;
struct quantiles quantiles;
};
static inline struct quantiles *time_stats_to_quantiles(struct bch2_time_stats *stats)
{
return stats->have_quantiles
? &container_of(stats, struct bch2_time_stats_quantiles, stats)->quantiles
: NULL;
}
void __bch2_time_stats_clear_buffer(struct bch2_time_stats *, struct time_stat_buffer *);
void __bch2_time_stats_update(struct bch2_time_stats *stats, u64, u64);
@ -133,4 +145,15 @@ static inline bool track_event_change(struct bch2_time_stats *stats, bool v)
void bch2_time_stats_exit(struct bch2_time_stats *);
void bch2_time_stats_init(struct bch2_time_stats *);
static inline void bch2_time_stats_quantiles_exit(struct bch2_time_stats_quantiles *statq)
{
bch2_time_stats_exit(&statq->stats);
}
static inline void bch2_time_stats_quantiles_init(struct bch2_time_stats_quantiles *statq)
{
bch2_time_stats_init(&statq->stats);
statq->stats.have_quantiles = true;
memset(&statq->quantiles, 0, sizeof(statq->quantiles));
}
#endif /* _BCACHEFS_TIME_STATS_H */

7
fs/bcachefs/util.c
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@ -365,6 +365,7 @@ static inline void pr_name_and_units(struct printbuf *out, const char *name, u64
void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats)
{
struct quantiles *quantiles = time_stats_to_quantiles(stats);
s64 f_mean = 0, d_mean = 0;
u64 f_stddev = 0, d_stddev = 0;
@ -465,17 +466,17 @@ void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats
printbuf_tabstops_reset(out);
if (stats->quantiles_enabled) {
if (quantiles) {
int i = eytzinger0_first(NR_QUANTILES);
const struct time_unit *u =
bch2_pick_time_units(stats->quantiles.entries[i].m);
bch2_pick_time_units(quantiles->entries[i].m);
u64 last_q = 0;
prt_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(stats->quantiles.entries[i].m, last_q);
u64 q = max(quantiles->entries[i].m, last_q);
prt_printf(out, "%llu ", div_u64(q, u->nsecs));
if (is_last)
prt_newline(out);