[PATCH 3/5] bcachefs: bch2_time_stats_to_seq_buf()

From: Kent Overstreet
Date: Fri Jan 26 2024 - 17:09:59 EST


Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
---
fs/bcachefs/super.c | 2 +
fs/bcachefs/util.c | 129 +++++++++++++++++++++++++++++++++++++++-----
fs/bcachefs/util.h | 4 ++
3 files changed, 121 insertions(+), 14 deletions(-)

diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index da8697c79a97..e74534096cb5 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -1262,6 +1262,8 @@ static struct bch_dev *__bch2_dev_alloc(struct bch_fs *c,

bch2_time_stats_init(&ca->io_latency[READ]);
bch2_time_stats_init(&ca->io_latency[WRITE]);
+ ca->io_latency[READ].quantiles_enabled = true;
+ ca->io_latency[WRITE].quantiles_enabled = true;

ca->mi = bch2_mi_to_cpu(member);

diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index c7cf9c6fcf9a..f2c8550c1331 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -505,10 +505,8 @@ 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)
{
- const struct time_unit *u;
s64 f_mean = 0, d_mean = 0;
- u64 q, last_q = 0, f_stddev = 0, d_stddev = 0;
- int i;
+ u64 f_stddev = 0, d_stddev = 0;

if (stats->buffer) {
int cpu;
@@ -607,19 +605,122 @@ void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats

printbuf_tabstops_reset(out);

- i = eytzinger0_first(NR_QUANTILES);
- u = pick_time_units(stats->quantiles.entries[i].m);
+ if (stats->quantiles_enabled) {
+ int i = eytzinger0_first(NR_QUANTILES);
+ const struct time_unit *u =
+ pick_time_units(stats->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);
+ prt_printf(out, "%llu ", div_u64(q, u->nsecs));
+ if (is_last)
+ prt_newline(out);
+ last_q = q;
+ }
+ }
+}
+
+#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);
+}
+
+void bch2_time_stats_to_seq_buf(struct seq_buf *out, struct bch2_time_stats *stats)
+{
+ s64 f_mean = 0, d_mean = 0;
+ u64 f_stddev = 0, d_stddev = 0;
+
+ if (stats->buffer) {
+ int cpu;

- prt_printf(out, "quantiles (%s):\t", u->name);
- eytzinger0_for_each(i, NR_QUANTILES) {
- bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1;
+ spin_lock_irq(&stats->lock);
+ for_each_possible_cpu(cpu)
+ __bch2_time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));
+ spin_unlock_irq(&stats->lock);
+ }

- q = max(stats->quantiles.entries[i].m, last_q);
- prt_printf(out, "%llu ",
- div_u64(q, u->nsecs));
- if (is_last)
- prt_newline(out);
- last_q = q;
+ /*
+ * avoid divide by zero
+ */
+ if (stats->freq_stats.n) {
+ 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);
+ }
+
+ seq_buf_printf(out, "count: %llu\n", stats->duration_stats.n);
+
+ seq_buf_printf(out, " since mount recent\n");
+
+ 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));
+ 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));
+ 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));
+ 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));
+ seq_buf_printf(out, "\n");
+
+ if (stats->quantiles_enabled) {
+ int i = eytzinger0_first(NR_QUANTILES);
+ const struct time_unit *u =
+ pick_time_units(stats->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);
+ seq_buf_printf(out, "%llu ", div_u64(q, u->nsecs));
+ if (is_last)
+ seq_buf_printf(out, "\n");
+ last_q = q;
+ }
}
}
#else
diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h
index c3b11c3d24ea..7ff2d4fe26f6 100644
--- a/fs/bcachefs/util.h
+++ b/fs/bcachefs/util.h
@@ -382,6 +382,7 @@ struct bch2_time_stat_buffer {

struct bch2_time_stats {
spinlock_t lock;
+ bool quantiles_enabled;
/* all fields are in nanoseconds */
u64 min_duration;
u64 max_duration;
@@ -435,6 +436,9 @@ static inline bool track_event_change(struct bch2_time_stats *stats,

void bch2_time_stats_to_text(struct printbuf *, struct bch2_time_stats *);

+struct seq_buf;
+void bch2_time_stats_to_seq_buf(struct seq_buf *, struct bch2_time_stats *);
+
void bch2_time_stats_exit(struct bch2_time_stats *);
void bch2_time_stats_init(struct bch2_time_stats *);

--
2.43.0