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

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.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 687986bb
// 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;
}
......@@ -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;
......
......@@ -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;
}
/* 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);
......
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