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: From: Adrian Hunter <[email protected]> Date: Mon, 26 Nov 2018 14:12:52 +0200 Subject: [PATCH] perf intel-pt: Fix error with config term pt=0 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 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c index db0ba8caf5a2..ba8ecaf52200 100644 --- a/tools/perf/arch/x86/util/intel-pt.c +++ b/tools/perf/arch/x86/util/intel-pt.c @@ -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); -- 2.17.1
