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From:   Thomas Richter <tmricht@linux.ibm.com>
To:     linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
        acme@kernel.org
Cc:     svens@linux.ibm.com, gor@linux.ibm.com, sumanthk@linux.ibm.com,
        heiko.carstens@de.ibm.com, kan.liang@linux.intel.com,
        Thomas Richter <tmricht@linux.ibm.com>
Subject: [PATCH] perf test: Test case 27 fails on s390 and non-x86 platforms
Date:   Tue,  2 Mar 2021 14:31:19 +0100
Message-Id: <20210302133119.3325530-1-tmricht@linux.ibm.com>
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Executing perf test 27 fails on s390:
 [root@t35lp46 perf]# ./perf test -Fv 27
 27: Sample parsing
 --- start ---
 ---- end ----
 Sample parsing: FAILED!
 [root@t35lp46 perf]#

The root cause is
commit c7444297fd3769 ("perf test: Support PERF_SAMPLE_WEIGHT_STRUCT")
This commit introduced a test case for PERF_SAMPLE_WEIGHT_STRUCT
but does not adjust non-x86 weak linkage functions.

The error is in test__sample_parsing() --> do_test()
Function do_test() defines two structures of type struct perf_sample named
sample and sample_out. The first sets member sample.ins_lat = 117

Structure sample_out is constructed dynamically using functions
perf_event__synthesize_sample() and evsel__parse_sample().
Both functions have an x86 specific function version which sets member
ins_lat. The weak common functions do not set member ins_lat.

Later in function samples_same() both data in variable sample and sample_out
are compared. The comparison fails because sample.ins_lat is 117
and samples_out.ins_lat is 0, the weak functions never set member ins_lat.

Output after:
 [root@t35lp46 perf]# ./perf test -Fv 27
 27: Sample parsing
 --- start ---
 ---- end ----
 Sample parsing: Ok
[root@t35lp46 perf]#

Fixes:
commit c7444297fd3769 ("perf test: Support PERF_SAMPLE_WEIGHT_STRUCT")

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
---
 tools/perf/util/evsel.c            | 8 +++++---
 tools/perf/util/synthetic-events.c | 6 +++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1bf76864c4f2..c9efed5c173d 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2106,10 +2106,12 @@ perf_event__check_size(union perf_event *event, unsigned int sample_size)
 }
 
 void __weak arch_perf_parse_sample_weight(struct perf_sample *data,
-					  const __u64 *array,
-					  u64 type __maybe_unused)
+					  const __u64 *array, u64 type)
 {
-	data->weight = *array;
+	if (type & PERF_SAMPLE_WEIGHT)
+		data->weight = *array & 0xffffffff;
+	if (type & PERF_SAMPLE_WEIGHT_STRUCT)
+		data->ins_lat = (*array >> 32) & 0xffff;
 }
 
 int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index b698046ec2db..af7ecbc57cbe 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -1507,9 +1507,13 @@ size_t perf_event__sample_event_size(const struct perf_sample *sample, u64 type,
 }
 
 void __weak arch_perf_synthesize_sample_weight(const struct perf_sample *data,
-					       __u64 *array, u64 type __maybe_unused)
+					       __u64 *array, u64 type)
 {
 	*array = data->weight;
+	if (type & PERF_SAMPLE_WEIGHT_STRUCT) {
+		*array &= 0xffffffff;
+		*array |= ((u64)data->ins_lat << 32);
+	}
 }
 
 int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_format,
-- 
2.29.2