Commit 75bcb877 authored Jun 30, 2020 by Adrian Hunter Committed by Arnaldo Carvalho de Melo Jul 06, 2020

perf intel-pt: Fix recording PEBS-via-PT with registers



When recording PEBS-via-PT, the kernel will not accept the intel_pt
event with register sampling e.g.

 # perf record --kcore -c 10000 -e '{intel_pt/branch=0/,branch-loads/aux-output/ppp}' -I -- ls -l
 Error:
 intel_pt/branch=0/: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'

Fix by suppressing register sampling on the intel_pt evsel.

Committer notes:

Adrian informed that this is only available from Tremont onwards, so on
older processors the error continues the same as before.

Fixes: 9e64cefe ("perf intel-pt: Process options for PEBS event synthesis")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Luwei Kang <luwei.kang@intel.com>
Link: http://lore.kernel.org/lkml/20200630133935.11150-2-adrian.hunter@intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent d61cbb85

tools/perf/arch/x86/util/intel-pt.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -641,6 +641,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
		}
		evsel->core.attr.freq = 0;
		evsel->core.attr.sample_period = 1;
		evsel->no_aux_samples = true;
		intel_pt_evsel = evsel;
		opts->full_auxtrace = true;
		}

tools/perf/util/evsel.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1014,12 +1014,12 @@ void evsel__config(struct evsel evsel, struct record_opts opts,
		if (callchain && callchain->enabled && !evsel->no_aux_samples)
		evsel__config_callchain(evsel, opts, callchain);

		if (opts->sample_intr_regs) {
		if (opts->sample_intr_regs && !evsel->no_aux_samples) {
		attr->sample_regs_intr = opts->sample_intr_regs;
		evsel__set_sample_bit(evsel, REGS_INTR);
		}

		if (opts->sample_user_regs) {
		if (opts->sample_user_regs && !evsel->no_aux_samples) {
		attr->sample_regs_user \|= opts->sample_user_regs;
		evsel__set_sample_bit(evsel, REGS_USER);
		}

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