When operating in CPU-wide mode tracers need to generate timestamps in order to correlate the code being traced on one CPU with what is executed on other CPUs.
Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org --- tools/perf/arch/arm/util/cs-etm.c | 49 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+)
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index f0f68c175038..dcf0fef9462f 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -92,6 +92,46 @@ static int cs_etm_set_context_id(struct perf_pmu *cs_etm_pmu, return err; }
+static int cs_etm_set_timestamp(struct perf_pmu *cs_etm_pmu, + struct perf_evsel *evsel, int cpu) +{ + char path[PATH_MAX]; + int err = -EINVAL; + u32 val; + + /* Get a handle on TRCIRD0 */ + snprintf(path, PATH_MAX, "cpu%d/%s", + cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]); + err = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val); + + /* There was a problem reading the file, bailing out */ + if (err != 1) { + pr_err("%s: can't read file %s\n", + CORESIGHT_ETM_PMU_NAME, path); + goto out; + } + + /* + * TRCIDR0.TSSIZE, bit [28-24], indicates whether global timestamping + * is supported: + * 0b00000 Global timestamping is not implemented + * 0b00110 Implementation supports a maximum timestamp of 48bits. + * 0b01000 Implementation supports a maximum timestamp of 64bits. + */ + val &= GENMASK(28, 24); + if (!val) { + err = -EINVAL; + goto out; + } + + /* All good, let the kernel know */ + evsel->attr.config |= (1 << ETM_OPT_TS); + err = 0; + +out: + return err; +} + static int cs_etm_set_option(struct auxtrace_record *itr, struct perf_evsel *evsel, u32 option) { @@ -115,6 +155,11 @@ static int cs_etm_set_option(struct auxtrace_record *itr, if (err) goto out; break; + case ETM_OPT_TS: + err = cs_etm_set_timestamp(cs_etm_pmu, evsel, i); + if (err) + goto out; + break; default: break; } @@ -298,6 +343,10 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_CTXTID); if (err) goto out; + + err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_TS); + if (err) + goto out; }
/* Add dummy event to keep tracking */