Em Wed, Nov 28, 2018 at 02:38:13PM +0200, Adrian Hunter escreveu: > On 27/11/18 2:39 PM, Arnaldo Carvalho de Melo wrote: > > Em Tue, Nov 27, 2018 at 10:43:36AM +0200, Adrian Hunter escreveu: > >> 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'. > >> > >> Signed-off-by: Adrian Hunter <[email protected]> > >> --- > >> tools/perf/arch/x86/util/intel-pt.c | 8 ++++++++ > >> 1 file changed, 8 insertions(+) > >> > >> diff --git a/tools/perf/arch/x86/util/intel-pt.c > >> b/tools/perf/arch/x86/util/intel-pt.c > >> index db0ba8caf5a2..af25a7824ee0 100644 > >> --- a/tools/perf/arch/x86/util/intel-pt.c > >> +++ b/tools/perf/arch/x86/util/intel-pt.c > >> @@ -524,10 +524,18 @@ 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; > > > > shouldn't we have a warning like: > > > > pr_warning("pt=0 doesn't make sense, forcing pt=1") > > > > > > Instead of silently doing something the user, mistakenly, did > > explicitely? > > Sure, here it is:
Thanks, sticked this to the cset: ------------------------ 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 ] # ------------------------ Thanks, applied. - Arnaldo
