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perf intel-pt: Fix error with config term "pt=0"

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Users should never use 'pt=0', but if they do it may give a meaningless
error:

	$ perf record -e intel_pt/pt=0/u uname
	Error:
	The sys_perf_event_open() syscall returned with 22 (Invalid argument) for
	event (intel_pt/pt=0/u).

Fix that by forcing 'pt=1'.

Committer testing:

  # perf record -e intel_pt/pt=0/u uname
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (intel_pt/pt=0/u).
  /bin/dmesg | grep -i perf may provide additional information.

  # perf record -e intel_pt/pt=0/u uname
  pt=0 doesn't make sense, forcing pt=1
  Linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.020 MB perf.data ]
  #

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/b7c5b4e5-9497-10e5-fd43-5f3e4a0fe51d@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2018-11-26 14:12:52 +02:00 committed by Arnaldo Carvalho de Melo
parent 1b3aae90c6
commit 1c6f709b9f
1 changed files with 11 additions and 0 deletions
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11
tools/perf/arch/x86/util/intel-pt.c
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@ -524,10 +524,21 @@ static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
struct perf_evsel *evsel)
{
int err;
char c;
if (!evsel)
return 0;
/*
* If supported, force pass-through config term (pt=1) even if user
* sets pt=0, which avoids senseless kernel errors.
*/
if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 &&
!(evsel->attr.config & 1)) {
pr_warning("pt=0 doesn't make sense, forcing pt=1\n");
evsel->attr.config |= 1;
}
err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds",
"cyc_thresh", "caps/psb_cyc",
evsel->attr.config);