Re: [PATCH v11 perf, bpf-next 7/9] perf tools: synthesize PERF_RECORD_* for loaded BPF programs

On Tue, Jan 22, 2019 at 12:31:17PM -0200, Arnaldo Carvalho de Melo wrote:

Em Tue, Jan 22, 2019 at 12:13:20PM -0200, Arnaldo Carvalho de Melo escreveu:

quoted

Em Fri, Jan 18, 2019 at 11:46:55AM -0300, Arnaldo Carvalho de Melo escreveu:

quoted

Em Thu, Jan 17, 2019 at 08:15:19AM -0800, Song Liu escreveu:

quoted

This patch synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for
BPF programs loaded before perf-record. This is achieved by gathering
information about all BPF programs via sys_bpf.

Ditto

This is breaking 'perf sched', see below, the fix seems trivial:

[root@quaco ~]# perf sched record -a sleep 2
[ perf record: Woken up 1 times to write data ]
0x5b60 [0x138]: failed to process type: 17
[ perf record: Captured and wrote 1.539 MB perf.data ]
[root@quaco ~]# perf sched lat
0x5b60 [0x138]: failed to process type: 17
Failed to process events, error -22
[root@quaco ~]#

So:

   perf_session__process_event (event->header.type = 17 (PERF_RECORD_KSYMBOL)
     if (tool->ordered_events)
       ret = perf_evlist__parse_sample_timestamp(evlist, event, &timestamp);
       if (ret && ret != -1)
            return ret;

So it returns here with -EFAULT, i.e. this is failing:

int perf_evlist__parse_sample_timestamp(struct perf_evlist *evlist,
                                        union perf_event *event,
                                        u64 *timestamp)
{
        struct perf_evsel *evsel = perf_evlist__event2evsel(evlist, event);

        if (!evsel)
                return -EFAULT;
        return perf_evsel__parse_sample_timestamp(evsel, event, timestamp);
}

It isn't mapping the event ID it finds back to an evsel.. Jiri, ideas?

This is happening so far only for 'perf sched', perf record with two
events works.

I saw also perf mem failing because of this.. will check

jirka