linux-kernel - Re: [PATCH] perf report: Fix regression when decoding intelPT traces

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Date:   Thu, 14 Dec 2017 09:03:44 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] perf report: Fix regression when decoding intelPT traces

On 14 December 2017 at 08:28, Jiri Olsa <jolsa@...hat.com> wrote:
> On Wed, Dec 13, 2017 at 05:57:54PM -0700, Mathieu Poirier wrote:
>> Commit (93d10af26bb7 perf tools: Optimize sample parsing for ordered
>> events) breaks intelPT trace decoding by invariably returning an error if
>> the event type isn't a PERF_SAMPLE_TIME.
>
> right, thanks for catchng that
>
>>
>> With this patch the timestamp is initialised and processing is allowed to
>> continue even if an error is returned by function
>> perf_evlist__parse_sample_timestamp().
>>
>> Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
>> ---
>>  tools/perf/util/session.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
>> index 54e30f1bcbd7..20cdcf14232b 100644
>> --- a/tools/perf/util/session.c
>> +++ b/tools/perf/util/session.c
>> @@ -1512,7 +1512,7 @@ static s64 perf_session__process_event(struct perf_session *session,
>>
>>               ret = perf_evlist__parse_sample_timestamp(evlist, event, &timestamp);
>>               if (ret)
>> -                     return ret;
>> +                     timestamp = -1ULL;
>
> we still have some -EFAULT error codes in there that we
> want to catch.. should it be more like in below?
>
> thanks,
> jirka
>
>
> ---
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 54e30f1bcbd7..9498aa0efe39 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1508,10 +1508,10 @@ static s64 perf_session__process_event(struct perf_session *session,
>                 return perf_session__process_user_event(session, event, file_offset);
>
>         if (tool->ordered_events) {
> -               u64 timestamp;
> +               u64 timestamp = -1ULL
>
>                 ret = perf_evlist__parse_sample_timestamp(evlist, event, &timestamp);
> -               if (ret)
> +               if (ret != -1)
>                         return ret;

Yes, that's better  - I'll send another revision.

>
>                 ret = perf_session__queue_event(session, event, timestamp, file_offset);