From: Darrick J. Wong <djwong@xxxxxxxxxx>
Export json versions of time statistics information. Given the tabular
nature of the numbers exposed, this will make it a lot easier for higher
(than C) level languages (e.g. python) to import information without
needing to write yet another clumsy string parser.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
---
include/linux/time_stats.h | 2 +
lib/time_stats.c | 87 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 89 insertions(+)
diff --git a/include/linux/time_stats.h b/include/linux/time_stats.h
index b3c810fff963a..4e1f5485ed039 100644
--- a/include/linux/time_stats.h
+++ b/include/linux/time_stats.h
@@ -156,6 +156,8 @@ static inline bool track_event_change(struct time_stats *stats, bool v)
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 *);
diff --git a/lib/time_stats.c b/lib/time_stats.c
index 0fb3d854e503b..c0f209dd9f6dd 100644
--- a/lib/time_stats.c
+++ b/lib/time_stats.c
@@ -266,6 +266,93 @@ void time_stats_to_seq_buf(struct seq_buf *out, struct time_stats *stats,
}
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);
