Commit acb65150 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf record: Support sample-read topdown metric group 



With the hardware TopDown metrics feature, sample-read feature should be
supported for a topdown group, e.g., sample a non-topdown event and read
a topdown metric group. But the current perf record code errors out.

For a topdown metric group, the slots event must be the leader of the
group, but the leader slots event doesn't support sampling.

To support sample-read the topdown metric group, use the 2nd event of
the group as the "leader" for the purposes of sampling.

Only the platform with Topdown metic feature supports sample-read the
topdown group. Add arch_topdown_sample_read() to indicate whether the
topdown group supports sample-read.

Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200911144808.27603-3-kan.liang@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 687986bb

tools/perf/arch/x86/util/topdown.c

+35 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <stdio.h>

#include "api/fs/fs.h"

#include "util/pmu.h"

#include "util/topdown.h"



/*
@@ -26,3 +27,37 @@ void arch_topdown_group_warn(void) 
		"nmi_watchdog enabled with topdown. May give wrong results.\n"

		"Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");

}



#define TOPDOWN_SLOTS		0x0400



static bool is_topdown_slots_event(struct evsel *counter)

{

	if (!counter->pmu_name)

		return false;



	if (strcmp(counter->pmu_name, "cpu"))

		return false;



	if (counter->core.attr.config == TOPDOWN_SLOTS)

		return true;



	return false;

}



/*

 * Check whether a topdown group supports sample-read.

 *

 * Only Topdown metic supports sample-read. The slots

 * event must be the leader of the topdown group.

 */



bool arch_topdown_sample_read(struct evsel *leader)

{

	if (!pmu_have_event("cpu", "slots"))

		return false;



	if (is_topdown_slots_event(leader))

		return true;



	return false;

}

tools/perf/util/record.c

+2 −1
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include "util/perf_api_probe.h"

#include "record.h"

#include "../perf-sys.h"

#include "topdown.h"



/*

 * evsel__config_leader_sampling() uses special rules for leader sampling.
@@ -24,7 +25,7 @@ static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evl 
{

	struct evsel *leader = evsel->leader;



	if (evsel__is_aux_event(leader)) {

	if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader)) {

		evlist__for_each_entry(evlist, evsel) {

			if (evsel->leader == leader && evsel != evsel->leader)

				return evsel;

tools/perf/util/topdown.c

+5 −0
Original line number Diff line number Diff line
@@ -51,3 +51,8 @@ __weak bool arch_topdown_check_group(bool *warn) 
__weak void arch_topdown_group_warn(void)

{

}



__weak bool arch_topdown_sample_read(struct evsel *leader __maybe_unused)

{

	return false;

}

tools/perf/util/topdown.h

+2 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef TOPDOWN_H

#define TOPDOWN_H 1

#include "evsel.h"



bool arch_topdown_check_group(bool *warn);

void arch_topdown_group_warn(void);

bool arch_topdown_sample_read(struct evsel *leader);



int topdown_filter_events(const char **attr, char **str, bool use_group);