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SubjectRe: [PATCH] perf test: Test case 27 fails on s390 and non-x86 platforms
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+ Athira Rajeev

On 3/2/2021 8:31 AM, Thomas Richter wrote:
> 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.
>

I don't think Power supports the instruction latency. As a request from
Athira Rajeev, I moved the PERF_SAMPLE_WEIGHT_STRUCT to the X86 specific
codes.
https://lore.kernel.org/lkml/D97FEF4F-DD88-4760-885E-9A6161A9B48B@linux.vnet.ibm.com/
https://lore.kernel.org/lkml/1612540912-6562-1-git-send-email-kan.liang@linux.intel.com/

I don't think we want to add the ins_lat back in the weak common functions.

Could you please update the perf test and don't apply the
PERF_SAMPLE_WEIGHT_STRUCT for the non-X86 platform?


> 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")

I think the regression should start from
commit fbefe9c2f87f ("perf tools: Support arch specific
PERF_SAMPLE_WEIGHT_STRUCT processing")


Thanks,
Kan
>
> 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,
>

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