Merge branch 'for-6.15/amd_sfh' into for-linus

From: Mario Limonciello <mario.limonciello@amd.com>

Some platforms include a human presence detection (HPD) sensor. When
enabled and a user is detected a wake event will be emitted from the
sensor fusion hub that software can react to.

Example use cases are "wake from suspend on approach" or to "lock
when leaving".

This is currently enabled by default on supported systems, but users
can't control it. This essentially means that wake on approach is
enabled which is a really surprising behavior to users that don't
expect it.

Instead of defaulting to enabled add a sysfs knob that users can
use to enable the feature if desirable and set it to disabled by
default.

1 files changed, 133 insertions, 109 deletions

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 53dcdf07f5a21..ba79f73e1cf5b 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -114,23 +114,59 @@ static void print_running_csv(struct perf_stat_config *config, u64 run, u64 ena)
 	fprintf(config->output, "%s%" PRIu64 "%s%.2f",
 		config->csv_sep, run, config->csv_sep, enabled_percent);
 }
+struct outstate {
+	/* Std mode: insert a newline before the next metric */
+	bool newline;
+	/* JSON mode: track need for comma for a previous field or not */
+	bool first;
+	/* Num CSV separators remaining to pad out when not all fields are printed */
+	int  csv_col_pad;
+
+	/*
+	 * The following don't track state across fields, but are here as a shortcut to
+	 * pass data to the print functions. The alternative would be to update the
+	 * function signatures of the entire print stack to pass them through.
+	 */
+	/* Place to output to */
+	FILE * const fh;
+	/* Lines are timestamped in --interval-print mode */
+	char timestamp[64];
+	/* Num items aggregated in current line. See struct perf_stat_aggr.nr */
+	int aggr_nr;
+	/* Core/socket/die etc ID for the current line */
+	struct aggr_cpu_id id;
+	/* Event for current line */
+	struct evsel *evsel;
+	/* Cgroup for current line */
+	struct cgroup *cgrp;
+};
+
+static const char *json_sep(struct outstate *os)
+{
+	const char *sep = os->first ? "" : ", ";
+
+	os->first = false;
+	return sep;
+}
+
+#define json_out(os, format, ...) fprintf((os)->fh, "%s" format, json_sep(os), ##__VA_ARGS__)
 
-static void print_running_json(struct perf_stat_config *config, u64 run, u64 ena)
+static void print_running_json(struct outstate *os, u64 run, u64 ena)
 {
 	double enabled_percent = 100;
 
 	if (run != ena)
 		enabled_percent = 100 * run / ena;
-	fprintf(config->output, "\"event-runtime\" : %" PRIu64 ", \"pcnt-running\" : %.2f, ",
-		run, enabled_percent);
+	json_out(os, "\"event-runtime\" : %" PRIu64 ", \"pcnt-running\" : %.2f",
+		 run, enabled_percent);
 }
 
-static void print_running(struct perf_stat_config *config,
+static void print_running(struct perf_stat_config *config, struct outstate *os,
 			  u64 run, u64 ena, bool before_metric)
 {
 	if (config->json_output) {
 		if (before_metric)
-			print_running_json(config, run, ena);
+			print_running_json(os, run, ena);
 	} else if (config->csv_output) {
 		if (before_metric)
 			print_running_csv(config, run, ena);
@@ -153,20 +189,20 @@ static void print_noise_pct_csv(struct perf_stat_config *config,
 	fprintf(config->output, "%s%.2f%%", config->csv_sep, pct);
 }
 
-static void print_noise_pct_json(struct perf_stat_config *config,
+static void print_noise_pct_json(struct outstate *os,
 				 double pct)
 {
-	fprintf(config->output, "\"variance\" : %.2f, ", pct);
+	json_out(os, "\"variance\" : %.2f", pct);
 }
 
-static void print_noise_pct(struct perf_stat_config *config,
+static void print_noise_pct(struct perf_stat_config *config, struct outstate *os,
 			    double total, double avg, bool before_metric)
 {
 	double pct = rel_stddev_stats(total, avg);
 
 	if (config->json_output) {
 		if (before_metric)
-			print_noise_pct_json(config, pct);
+			print_noise_pct_json(os, pct);
 	} else if (config->csv_output) {
 		if (before_metric)
 			print_noise_pct_csv(config, pct);
@@ -176,7 +212,7 @@ static void print_noise_pct(struct perf_stat_config *config,
 	}
 }
 
-static void print_noise(struct perf_stat_config *config,
+static void print_noise(struct perf_stat_config *config, struct outstate *os,
 			struct evsel *evsel, double avg, bool before_metric)
 {
 	struct perf_stat_evsel *ps;
@@ -185,7 +221,7 @@ static void print_noise(struct perf_stat_config *config,
 		return;
 
 	ps = evsel->stats;
-	print_noise_pct(config, stddev_stats(&ps->res_stats), avg, before_metric);
+	print_noise_pct(config, os, stddev_stats(&ps->res_stats), avg, before_metric);
 }
 
 static void print_cgroup_std(struct perf_stat_config *config, const char *cgrp_name)
@@ -198,18 +234,19 @@ static void print_cgroup_csv(struct perf_stat_config *config, const char *cgrp_n
 	fprintf(config->output, "%s%s", config->csv_sep, cgrp_name);
 }
 
-static void print_cgroup_json(struct perf_stat_config *config, const char *cgrp_name)
+static void print_cgroup_json(struct outstate *os, const char *cgrp_name)
 {
-	fprintf(config->output, "\"cgroup\" : \"%s\", ", cgrp_name);
+	json_out(os, "\"cgroup\" : \"%s\"", cgrp_name);
 }
 
-static void print_cgroup(struct perf_stat_config *config, struct cgroup *cgrp)
+static void print_cgroup(struct perf_stat_config *config, struct outstate *os,
+			 struct cgroup *cgrp)
 {
 	if (nr_cgroups || config->cgroup_list) {
 		const char *cgrp_name = cgrp ? cgrp->name  : "";
 
 		if (config->json_output)
-			print_cgroup_json(config, cgrp_name);
+			print_cgroup_json(os, cgrp_name);
 		else if (config->csv_output)
 			print_cgroup_csv(config, cgrp_name);
 		else
@@ -324,47 +361,45 @@ static void print_aggr_id_csv(struct perf_stat_config *config,
 	}
 }
 
-static void print_aggr_id_json(struct perf_stat_config *config,
+static void print_aggr_id_json(struct perf_stat_config *config, struct outstate *os,
 			       struct evsel *evsel, struct aggr_cpu_id id, int aggr_nr)
 {
-	FILE *output = config->output;
-
 	switch (config->aggr_mode) {
 	case AGGR_CORE:
-		fprintf(output, "\"core\" : \"S%d-D%d-C%d\", \"aggregate-number\" : %d, ",
+		json_out(os, "\"core\" : \"S%d-D%d-C%d\", \"aggregate-number\" : %d",
 			id.socket, id.die, id.core, aggr_nr);
 		break;
 	case AGGR_CACHE:
-		fprintf(output, "\"cache\" : \"S%d-D%d-L%d-ID%d\", \"aggregate-number\" : %d, ",
+		json_out(os, "\"cache\" : \"S%d-D%d-L%d-ID%d\", \"aggregate-number\" : %d",
 			id.socket, id.die, id.cache_lvl, id.cache, aggr_nr);
 		break;
 	case AGGR_CLUSTER:
-		fprintf(output, "\"cluster\" : \"S%d-D%d-CLS%d\", \"aggregate-number\" : %d, ",
+		json_out(os, "\"cluster\" : \"S%d-D%d-CLS%d\", \"aggregate-number\" : %d",
 			id.socket, id.die, id.cluster, aggr_nr);
 		break;
 	case AGGR_DIE:
-		fprintf(output, "\"die\" : \"S%d-D%d\", \"aggregate-number\" : %d, ",
+		json_out(os, "\"die\" : \"S%d-D%d\", \"aggregate-number\" : %d",
 			id.socket, id.die, aggr_nr);
 		break;
 	case AGGR_SOCKET:
-		fprintf(output, "\"socket\" : \"S%d\", \"aggregate-number\" : %d, ",
+		json_out(os, "\"socket\" : \"S%d\", \"aggregate-number\" : %d",
 			id.socket, aggr_nr);
 		break;
 	case AGGR_NODE:
-		fprintf(output, "\"node\" : \"N%d\", \"aggregate-number\" : %d, ",
+		json_out(os, "\"node\" : \"N%d\", \"aggregate-number\" : %d",
 			id.node, aggr_nr);
 		break;
 	case AGGR_NONE:
 		if (evsel->percore && !config->percore_show_thread) {
-			fprintf(output, "\"core\" : \"S%d-D%d-C%d\"",
+			json_out(os, "\"core\" : \"S%d-D%d-C%d\"",
 				id.socket, id.die, id.core);
 		} else if (id.cpu.cpu > -1) {
-			fprintf(output, "\"cpu\" : \"%d\", ",
+			json_out(os, "\"cpu\" : \"%d\"",
 				id.cpu.cpu);
 		}
 		break;
 	case AGGR_THREAD:
-		fprintf(output, "\"thread\" : \"%s-%d\", ",
+		json_out(os, "\"thread\" : \"%s-%d\"",
 			perf_thread_map__comm(evsel->core.threads, id.thread_idx),
 			perf_thread_map__pid(evsel->core.threads, id.thread_idx));
 		break;
@@ -376,29 +411,17 @@ static void print_aggr_id_json(struct perf_stat_config *config,
 	}
 }
 
-static void aggr_printout(struct perf_stat_config *config,
+static void aggr_printout(struct perf_stat_config *config, struct outstate *os,
 			  struct evsel *evsel, struct aggr_cpu_id id, int aggr_nr)
 {
 	if (config->json_output)
-		print_aggr_id_json(config, evsel, id, aggr_nr);
+		print_aggr_id_json(config, os, evsel, id, aggr_nr);
 	else if (config->csv_output)
 		print_aggr_id_csv(config, evsel, id, aggr_nr);
 	else
 		print_aggr_id_std(config, evsel, id, aggr_nr);
 }
 
-struct outstate {
-	FILE *fh;
-	bool newline;
-	bool first;
-	const char *prefix;
-	int  nfields;
-	int  aggr_nr;
-	struct aggr_cpu_id id;
-	struct evsel *evsel;
-	struct cgroup *cgrp;
-};
-
 static void new_line_std(struct perf_stat_config *config __maybe_unused,
 			 void *ctx)
 {
@@ -411,9 +434,9 @@ static inline void __new_line_std_csv(struct perf_stat_config *config,
 				      struct outstate *os)
 {
 	fputc('\n', os->fh);
-	if (os->prefix)
-		fputs(os->prefix, os->fh);
-	aggr_printout(config, os->evsel, os->id, os->aggr_nr);
+	if (config->interval)
+		fputs(os->timestamp, os->fh);
+	aggr_printout(config, os, os->evsel, os->id, os->aggr_nr);
 }
 
 static inline void __new_line_std(struct outstate *os)
@@ -464,7 +487,7 @@ static void new_line_csv(struct perf_stat_config *config, void *ctx)
 	int i;
 
 	__new_line_std_csv(config, os);
-	for (i = 0; i < os->nfields; i++)
+	for (i = 0; i < os->csv_col_pad; i++)
 		fputs(config->csv_sep, os->fh);
 }
 
@@ -499,9 +522,9 @@ static void print_metric_json(struct perf_stat_config *config __maybe_unused,
 	FILE *out = os->fh;
 
 	if (unit) {
-		fprintf(out, "\"metric-value\" : \"%f\", \"metric-unit\" : \"%s\"", val, unit);
+		json_out(os, "\"metric-value\" : \"%f\", \"metric-unit\" : \"%s\"", val, unit);
 		if (thresh != METRIC_THRESHOLD_UNKNOWN) {
-			fprintf(out, ", \"metric-threshold\" : \"%s\"",
+			json_out(os, "\"metric-threshold\" : \"%s\"",
 				metric_threshold_classify__str(thresh));
 		}
 	}
@@ -514,9 +537,11 @@ static void new_line_json(struct perf_stat_config *config, void *ctx)
 	struct outstate *os = ctx;
 
 	fputs("\n{", os->fh);
-	if (os->prefix)
-		fprintf(os->fh, "%s", os->prefix);
-	aggr_printout(config, os->evsel, os->id, os->aggr_nr);
+	os->first = true;
+	if (config->interval)
+		json_out(os, "%s", os->timestamp);
+
+	aggr_printout(config, os, os->evsel, os->id, os->aggr_nr);
 }
 
 static void print_metricgroup_header_json(struct perf_stat_config *config,
@@ -526,7 +551,7 @@ static void print_metricgroup_header_json(struct perf_stat_config *config,
 	if (!metricgroup_name)
 		return;
 
-	fprintf(config->output, "\"metricgroup\" : \"%s\"}", metricgroup_name);
+	json_out((struct outstate *) ctx, "\"metricgroup\" : \"%s\"}", metricgroup_name);
 	new_line_json(config, ctx);
 }
 
@@ -539,12 +564,12 @@ static void print_metricgroup_header_csv(struct perf_stat_config *config,
 
 	if (!metricgroup_name) {
 		/* Leave space for running and enabling */
-		for (i = 0; i < os->nfields - 2; i++)
+		for (i = 0; i < os->csv_col_pad - 2; i++)
 			fputs(config->csv_sep, os->fh);
 		return;
 	}
 
-	for (i = 0; i < os->nfields; i++)
+	for (i = 0; i < os->csv_col_pad; i++)
 		fputs(config->csv_sep, os->fh);
 	fprintf(config->output, "%s", metricgroup_name);
 	new_line_csv(config, ctx);
@@ -644,7 +669,6 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
 				  const char *unit, double val)
 {
 	struct outstate *os = ctx;
-	FILE *out = os->fh;
 	char buf[64], *ends;
 	char tbuf[1024];
 	const char *vals;
@@ -661,13 +685,7 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
 	*ends = 0;
 	if (!vals[0])
 		vals = "none";
-	fprintf(out, "%s\"%s\" : \"%s\"", os->first ? "" : ", ", unit, vals);
-	os->first = false;
-}
-
-static void new_line_metric(struct perf_stat_config *config __maybe_unused,
-			    void *ctx __maybe_unused)
-{
+	json_out(os, "\"%s\" : \"%s\"", unit, vals);
 }
 
 static void print_metric_header(struct perf_stat_config *config,
@@ -743,28 +761,27 @@ static void print_counter_value_csv(struct perf_stat_config *config,
 	fprintf(output, "%s", evsel__name(evsel));
 }
 
-static void print_counter_value_json(struct perf_stat_config *config,
+static void print_counter_value_json(struct outstate *os,
 				     struct evsel *evsel, double avg, bool ok)
 {
-	FILE *output = config->output;
 	const char *bad_count = evsel->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED;
 
 	if (ok)
-		fprintf(output, "\"counter-value\" : \"%f\", ", avg);
+		json_out(os, "\"counter-value\" : \"%f\"", avg);
 	else
-		fprintf(output, "\"counter-value\" : \"%s\", ", bad_count);
+		json_out(os, "\"counter-value\" : \"%s\"", bad_count);
 
 	if (evsel->unit)
-		fprintf(output, "\"unit\" : \"%s\", ", evsel->unit);
+		json_out(os, "\"unit\" : \"%s\"", evsel->unit);
 
-	fprintf(output, "\"event\" : \"%s\", ", evsel__name(evsel));
+	json_out(os, "\"event\" : \"%s\"", evsel__name(evsel));
 }
 
-static void print_counter_value(struct perf_stat_config *config,
+static void print_counter_value(struct perf_stat_config *config, struct outstate *os,
 				struct evsel *evsel, double avg, bool ok)
 {
 	if (config->json_output)
-		print_counter_value_json(config, evsel, avg, ok);
+		print_counter_value_json(os, evsel, avg, ok);
 	else if (config->csv_output)
 		print_counter_value_csv(config, evsel, avg, ok);
 	else
@@ -772,12 +789,13 @@ static void print_counter_value(struct perf_stat_config *config,
 }
 
 static void abs_printout(struct perf_stat_config *config,
+			 struct outstate *os,
 			 struct aggr_cpu_id id, int aggr_nr,
 			 struct evsel *evsel, double avg, bool ok)
 {
-	aggr_printout(config, evsel, id, aggr_nr);
-	print_counter_value(config, evsel, avg, ok);
-	print_cgroup(config, evsel->cgrp);
+	aggr_printout(config, os, evsel, id, aggr_nr);
+	print_counter_value(config, os, evsel, avg, ok);
+	print_cgroup(config, os, evsel->cgrp);
 }
 
 static bool is_mixed_hw_group(struct evsel *counter)
@@ -831,22 +849,23 @@ static void printout(struct perf_stat_config *config, struct outstate *os,
 
 	if (config->csv_output) {
 		pm = config->metric_only ? print_metric_only_csv : print_metric_csv;
-		nl = config->metric_only ? new_line_metric : new_line_csv;
+		nl = config->metric_only ? NULL : new_line_csv;
 		pmh = print_metricgroup_header_csv;
-		os->nfields = 4 + (counter->cgrp ? 1 : 0);
+		os->csv_col_pad = 4 + (counter->cgrp ? 1 : 0);
 	} else if (config->json_output) {
 		pm = config->metric_only ? print_metric_only_json : print_metric_json;
-		nl = config->metric_only ? new_line_metric : new_line_json;
+		nl = config->metric_only ? NULL : new_line_json;
 		pmh = print_metricgroup_header_json;
 	} else {
 		pm = config->metric_only ? print_metric_only : print_metric_std;
-		nl = config->metric_only ? new_line_metric : new_line_std;
+		nl = config->metric_only ? NULL : new_line_std;
 		pmh = print_metricgroup_header_std;
 	}
 
 	if (run == 0 || ena == 0 || counter->counts->scaled == -1) {
 		if (config->metric_only) {
-			pm(config, os, METRIC_THRESHOLD_UNKNOWN, "", "", 0);
+			pm(config, os, METRIC_THRESHOLD_UNKNOWN, /*format=*/NULL,
+			   /*unit=*/NULL, /*val=*/0);
 			return;
 		}
 
@@ -868,17 +887,17 @@ static void printout(struct perf_stat_config *config, struct outstate *os,
 	out.force_header = false;
 
 	if (!config->metric_only && !counter->default_metricgroup) {
-		abs_printout(config, os->id, os->aggr_nr, counter, uval, ok);
+		abs_printout(config, os, os->id, os->aggr_nr, counter, uval, ok);
 
-		print_noise(config, counter, noise, /*before_metric=*/true);
-		print_running(config, run, ena, /*before_metric=*/true);
+		print_noise(config, os, counter, noise, /*before_metric=*/true);
+		print_running(config, os, run, ena, /*before_metric=*/true);
 	}
 
 	if (ok) {
 		if (!config->metric_only && counter->default_metricgroup) {
 			void *from = NULL;
 
-			aggr_printout(config, os->evsel, os->id, os->aggr_nr);
+			aggr_printout(config, os, os->evsel, os->id, os->aggr_nr);
 			/* Print out all the metricgroup with the same metric event. */
 			do {
 				int num = 0;
@@ -891,8 +910,8 @@ static void printout(struct perf_stat_config *config, struct outstate *os,
 						__new_line_std_csv(config, os);
 				}
 
-				print_noise(config, counter, noise, /*before_metric=*/true);
-				print_running(config, run, ena, /*before_metric=*/true);
+				print_noise(config, os, counter, noise, /*before_metric=*/true);
+				print_running(config, os, run, ena, /*before_metric=*/true);
 				from = perf_stat__print_shadow_stats_metricgroup(config, counter, aggr_idx,
 										 &num, from, &out,
 										 &config->metric_events);
@@ -901,12 +920,12 @@ static void printout(struct perf_stat_config *config, struct outstate *os,
 			perf_stat__print_shadow_stats(config, counter, uval, aggr_idx,
 						      &out, &config->metric_events);
 	} else {
-		pm(config, os, METRIC_THRESHOLD_UNKNOWN, /*format=*/NULL, /*unit=*/"", /*val=*/0);
+		pm(config, os, METRIC_THRESHOLD_UNKNOWN, /*format=*/NULL, /*unit=*/NULL, /*val=*/0);
 	}
 
 	if (!config->metric_only) {
-		print_noise(config, counter, noise, /*before_metric=*/false);
-		print_running(config, run, ena, /*before_metric=*/false);
+		print_noise(config, os, counter, noise, /*before_metric=*/false);
+		print_running(config, os, run, ena, /*before_metric=*/false);
 	}
 }
 
@@ -1083,12 +1102,17 @@ static void print_counter_aggrdata(struct perf_stat_config *config,
 		return;
 
 	if (!metric_only) {
-		if (config->json_output)
+		if (config->json_output) {
+			os->first = true;
 			fputc('{', output);
-		if (os->prefix)
-			fprintf(output, "%s", os->prefix);
-		else if (config->summary && config->csv_output &&
-			 !config->no_csv_summary && !config->interval)
+		}
+		if (config->interval) {
+			if (config->json_output)
+				json_out(os, "%s", os->timestamp);
+			else
+				fprintf(output, "%s", os->timestamp);
+		} else if (config->summary && config->csv_output &&
+			   !config->no_csv_summary)
 			fprintf(output, "%s%s", "summary", config->csv_sep);
 	}
 
@@ -1114,15 +1138,19 @@ static void print_metric_begin(struct perf_stat_config *config,
 
 	if (config->json_output)
 		fputc('{', config->output);
-	if (os->prefix)
-		fprintf(config->output, "%s", os->prefix);
 
+	if (config->interval) {
+		if (config->json_output)
+			json_out(os, "%s", os->timestamp);
+		else
+			fprintf(config->output, "%s", os->timestamp);
+	}
 	evsel = evlist__first(evlist);
 	id = config->aggr_map->map[aggr_idx];
 	aggr = &evsel->stats->aggr[aggr_idx];
-	aggr_printout(config, evsel, id, aggr->nr);
+	aggr_printout(config, os, evsel, id, aggr->nr);
 
-	print_cgroup(config, os->cgrp ? : evsel->cgrp);
+	print_cgroup(config, os, os->cgrp ? : evsel->cgrp);
 }
 
 static void print_metric_end(struct perf_stat_config *config, struct outstate *os)
@@ -1301,7 +1329,7 @@ static void print_metric_headers(struct perf_stat_config *config,
 	struct perf_stat_output_ctx out = {
 		.ctx = &os,
 		.print_metric = print_metric_header,
-		.new_line = new_line_metric,
+		.new_line = NULL,
 		.force_header = true,
 	};
 
@@ -1336,20 +1364,20 @@ static void print_metric_headers(struct perf_stat_config *config,
 		fputc('\n', config->output);
 }
 
-static void prepare_interval(struct perf_stat_config *config,
-			     char *prefix, size_t len, struct timespec *ts)
+static void prepare_timestamp(struct perf_stat_config *config,
+			      struct outstate *os, struct timespec *ts)
 {
 	if (config->iostat_run)
 		return;
 
 	if (config->json_output)
-		scnprintf(prefix, len, "\"interval\" : %lu.%09lu, ",
+		scnprintf(os->timestamp, sizeof(os->timestamp), "\"interval\" : %lu.%09lu",
 			  (unsigned long) ts->tv_sec, ts->tv_nsec);
 	else if (config->csv_output)
-		scnprintf(prefix, len, "%lu.%09lu%s",
+		scnprintf(os->timestamp, sizeof(os->timestamp), "%lu.%09lu%s",
 			  (unsigned long) ts->tv_sec, ts->tv_nsec, config->csv_sep);
 	else
-		scnprintf(prefix, len, "%6lu.%09lu ",
+		scnprintf(os->timestamp, sizeof(os->timestamp), "%6lu.%09lu ",
 			  (unsigned long) ts->tv_sec, ts->tv_nsec);
 }
 
@@ -1557,7 +1585,7 @@ static void print_footer(struct perf_stat_config *config)
 		fprintf(output, " %17.*f +- %.*f seconds time elapsed",
 			precision, avg, precision, sd);
 
-		print_noise_pct(config, sd, avg, /*before_metric=*/false);
+		print_noise_pct(config, NULL, sd, avg, /*before_metric=*/false);
 	}
 	fprintf(output, "\n\n");
 
@@ -1672,9 +1700,7 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
 			    int argc, const char **argv)
 {
 	bool metric_only = config->metric_only;
-	int interval = config->interval;
 	struct evsel *counter;
-	char buf[64];
 	struct outstate os = {
 		.fh = config->output,
 		.first = true,
@@ -1685,10 +1711,8 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
 	if (config->iostat_run)
 		evlist->selected = evlist__first(evlist);
 
-	if (interval) {
-		os.prefix = buf;
-		prepare_interval(config, buf, sizeof(buf), ts);
-	}
+	if (config->interval)
+		prepare_timestamp(config, &os, ts);
 
 	print_header(config, _target, evlist, argc, argv);
 
@@ -1707,7 +1731,7 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
 	case AGGR_THREAD:
 	case AGGR_GLOBAL:
 		if (config->iostat_run) {
-			iostat_print_counters(evlist, config, ts, buf,
+			iostat_print_counters(evlist, config, ts, os.timestamp,
 					      (iostat_print_counter_t)print_counter, &os);
 		} else if (config->cgroup_list) {
 			print_cgroup_counter(config, evlist, &os);