This is a note to let you know that I've just added the patch titled
tracing: Add .percent suffix option to histogram values
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-add-.percent-suffix-option-to-histogram-valu.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit aa5e63131c95836508399c95d7db46f5581e9aa4
Author: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Date: Thu Oct 20 00:31:55 2022 +0900
tracing: Add .percent suffix option to histogram values
[ Upstream commit abaa5258ce5e5887a9de049f50a85dc023391a1c ]
Add .percent suffix option to show the histogram values in percentage.
This feature is useful when we need yo undersntand the overall trend
for the histograms of large values.
E.g. this shows the runtime percentage for each tasks.
------
# cd /sys/kernel/debug/tracing/
# echo hist:keys=pid:vals=hitcount,runtime.percent:sort=pid > \
events/sched/sched_stat_runtime/trigger
# sleep 10
# cat events/sched/sched_stat_runtime/hist
# event histogram
#
# trigger info: hist:keys=pid:vals=hitcount,runtime.percent:sort=pid:size=2048 [active]
#
{ pid: 8 } hitcount: 7 runtime (%): 4.14
{ pid: 14 } hitcount: 5 runtime (%): 3.69
{ pid: 16 } hitcount: 11 runtime (%): 3.41
{ pid: 61 } hitcount: 41 runtime (%): 19.75
{ pid: 65 } hitcount: 4 runtime (%): 1.48
{ pid: 70 } hitcount: 6 runtime (%): 3.60
{ pid: 72 } hitcount: 2 runtime (%): 1.10
{ pid: 144 } hitcount: 10 runtime (%): 32.01
{ pid: 151 } hitcount: 8 runtime (%): 22.66
{ pid: 152 } hitcount: 2 runtime (%): 8.10
Totals:
Hits: 96
Entries: 10
Dropped: 0
-----
Link: https://lore.kernel.org/linux-trace-kernel/166610813077.56030.4238090506973562347.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Reviewed-by: Tom Zanussi <zanussi@xxxxxxxxxx>
Tested-by: Tom Zanussi <zanussi@xxxxxxxxxx>
Stable-dep-of: e0213434fe3e ("tracing: Do not let histogram values have some modifiers")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 888980257340f..f714ed1f1c673 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5727,7 +5727,8 @@ static const char readme_msg[] =
"\t .syscall display a syscall id as a syscall name\n"
"\t .log2 display log2 value rather than raw number\n"
"\t .buckets=size display values in groups of size rather than raw number\n"
- "\t .usecs display a common_timestamp in microseconds\n\n"
+ "\t .usecs display a common_timestamp in microseconds\n"
+ "\t .percent display a number of percentage value\n\n"
"\t The 'pause' parameter can be used to pause an existing hist\n"
"\t trigger or to start a hist trigger but not log any events\n"
"\t until told to do so. 'continue' can be used to start or\n"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index e3df03cdecbcb..1c207fbf5634f 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -506,6 +506,7 @@ enum hist_field_flags {
HIST_FIELD_FL_ALIAS = 1 << 16,
HIST_FIELD_FL_BUCKET = 1 << 17,
HIST_FIELD_FL_CONST = 1 << 18,
+ HIST_FIELD_FL_PERCENT = 1 << 19,
};
struct var_defs {
@@ -1708,6 +1709,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
flags_str = "buckets";
else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
flags_str = "usecs";
+ else if (hist_field->flags & HIST_FIELD_FL_PERCENT)
+ flags_str = "percent";
return flags_str;
}
@@ -2320,6 +2323,10 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
if (ret || !(*buckets))
goto error;
*flags |= HIST_FIELD_FL_BUCKET;
+ } else if (strncmp(modifier, "percent", 7) == 0) {
+ if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
+ goto error;
+ *flags |= HIST_FIELD_FL_PERCENT;
} else {
error:
hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
@@ -5297,33 +5304,69 @@ static void hist_trigger_print_key(struct seq_file *m,
seq_puts(m, "}");
}
+/* Get the 100 times of the percentage of @val in @total */
+static inline unsigned int __get_percentage(u64 val, u64 total)
+{
+ if (!total)
+ goto div0;
+
+ if (val < (U64_MAX / 10000))
+ return (unsigned int)div64_ul(val * 10000, total);
+
+ total = div64_u64(total, 10000);
+ if (!total)
+ goto div0;
+
+ return (unsigned int)div64_ul(val, total);
+div0:
+ return val ? UINT_MAX : 0;
+}
+
+static void hist_trigger_print_val(struct seq_file *m, unsigned int idx,
+ const char *field_name, unsigned long flags,
+ u64 *totals, struct tracing_map_elt *elt)
+{
+ u64 val = tracing_map_read_sum(elt, idx);
+ unsigned int pc;
+
+ if (flags & HIST_FIELD_FL_PERCENT) {
+ pc = __get_percentage(val, totals[idx]);
+ if (pc == UINT_MAX)
+ seq_printf(m, " %s (%%):[ERROR]", field_name);
+ else
+ seq_printf(m, " %s (%%): %3u.%02u", field_name,
+ pc / 100, pc % 100);
+ } else if (flags & HIST_FIELD_FL_HEX) {
+ seq_printf(m, " %s: %10llx", field_name, val);
+ } else {
+ seq_printf(m, " %s: %10llu", field_name, val);
+ }
+}
+
static void hist_trigger_entry_print(struct seq_file *m,
struct hist_trigger_data *hist_data,
+ u64 *totals,
void *key,
struct tracing_map_elt *elt)
{
const char *field_name;
- unsigned int i;
+ unsigned int i = HITCOUNT_IDX;
+ unsigned long flags;
hist_trigger_print_key(m, hist_data, key, elt);
- seq_printf(m, " hitcount: %10llu",
- tracing_map_read_sum(elt, HITCOUNT_IDX));
+ /* At first, show the raw hitcount always */
+ hist_trigger_print_val(m, i, "hitcount", 0, totals, elt);
for (i = 1; i < hist_data->n_vals; i++) {
field_name = hist_field_name(hist_data->fields[i], 0);
+ flags = hist_data->fields[i]->flags;
- if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR ||
- hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR)
+ if (flags & HIST_FIELD_FL_VAR || flags & HIST_FIELD_FL_EXPR)
continue;
- if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
- seq_printf(m, " %s: %10llx", field_name,
- tracing_map_read_sum(elt, i));
- } else {
- seq_printf(m, " %s: %10llu", field_name,
- tracing_map_read_sum(elt, i));
- }
+ seq_puts(m, " ");
+ hist_trigger_print_val(m, i, field_name, flags, totals, elt);
}
print_actions(m, hist_data, elt);
@@ -5336,7 +5379,8 @@ static int print_entries(struct seq_file *m,
{
struct tracing_map_sort_entry **sort_entries = NULL;
struct tracing_map *map = hist_data->map;
- int i, n_entries;
+ int i, j, n_entries;
+ u64 *totals = NULL;
n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
hist_data->n_sort_keys,
@@ -5344,11 +5388,29 @@ static int print_entries(struct seq_file *m,
if (n_entries < 0)
return n_entries;
+ for (j = 0; j < hist_data->n_vals; j++) {
+ if (!(hist_data->fields[j]->flags & HIST_FIELD_FL_PERCENT))
+ continue;
+ if (!totals) {
+ totals = kcalloc(hist_data->n_vals, sizeof(u64),
+ GFP_KERNEL);
+ if (!totals) {
+ n_entries = -ENOMEM;
+ goto out;
+ }
+ }
+ for (i = 0; i < n_entries; i++)
+ totals[j] += tracing_map_read_sum(
+ sort_entries[i]->elt, j);
+ }
+
for (i = 0; i < n_entries; i++)
- hist_trigger_entry_print(m, hist_data,
+ hist_trigger_entry_print(m, hist_data, totals,
sort_entries[i]->key,
sort_entries[i]->elt);
+ kfree(totals);
+out:
tracing_map_destroy_sort_entries(sort_entries, n_entries);
return n_entries;
