linux-kernel - [PATCH 5/9] perf tools: Disable write_backward for leader sampling group events

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Date:   Mon, 23 Apr 2018 11:08:19 +0200
From:   Jiri Olsa <jolsa@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Kan Liang <kan.liang@...el.com>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        David Ahern <dsahern@...il.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: [PATCH 5/9] perf tools: Disable write_backward for leader sampling group events

.. and other related fields that do not need to be enabled
for events that have sampling leader.

It fixes the perf top usage Ingo reported broken:

  # perf top -e '{cycles,msr/aperf/}:S'

The msr/aperf/ is configured for write_back sampling, which
is not allowed by msr pmu, so it fails to create the event.

Adjusting related attr test.

Reported-by: Ingo Molnar <mingo@...nel.org>
Cc: Kan Liang <kan.liang@...el.com>
Link: http://lkml.kernel.org/n/tip-bh7wxrci19km6iwbv4qg555o@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 tools/perf/tests/attr/test-record-group-sampling | 3 +++
 tools/perf/util/evsel.c                          | 7 +++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/attr/test-record-group-sampling b/tools/perf/tests/attr/test-record-group-sampling
index f906b793196f..8a33ca4f9e1f 100644
--- a/tools/perf/tests/attr/test-record-group-sampling
+++ b/tools/perf/tests/attr/test-record-group-sampling
@@ -35,3 +35,6 @@ inherit=0
 # sampling disabled
 sample_freq=0
 sample_period=0
+freq=0
+write_backward=0
+sample_id_all=0
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 7472f876cd70..81b7f1cdc956 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -930,8 +930,11 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts,
 	 * than leader in case leader 'leads' the sampling.
 	 */
 	if ((leader != evsel) && leader->sample_read) {
-		attr->sample_freq   = 0;
-		attr->sample_period = 0;
+		attr->freq           = 0;
+		attr->sample_freq    = 0;
+		attr->sample_period  = 0;
+		attr->write_backward = 0;
+		attr->sample_id_all  = 0;
 	}
 
 	if (opts->no_samples)
-- 
2.13.6