On Fri, 7 Jun 2019 at 03:41, Suzuki K Poulose <[email protected]> wrote: > > > > On 24/05/2019 18:34, Mathieu Poirier wrote: > > 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 <[email protected]> > > --- > > tools/perf/arch/arm/util/cs-etm.c | 57 +++++++++++++++++++++++++++++++ > > 1 file changed, 57 insertions(+) > > > > diff --git a/tools/perf/arch/arm/util/cs-etm.c > > b/tools/perf/arch/arm/util/cs-etm.c > > index 3912f0bf04ed..be1e4f20affa 100644 > > --- a/tools/perf/arch/arm/util/cs-etm.c > > +++ b/tools/perf/arch/arm/util/cs-etm.c > > @@ -99,6 +99,54 @@ static int cs_etm_set_context_id(struct auxtrace_record > > *itr, > > return err; > > } > > > > +static int cs_etm_set_timestamp(struct auxtrace_record *itr, > > + struct perf_evsel *evsel, int cpu) > > +{ > > + struct cs_etm_recording *ptr; > > + struct perf_pmu *cs_etm_pmu; > > + char path[PATH_MAX]; > > + int err = -EINVAL; > > + u32 val; > > + > > + ptr = container_of(itr, struct cs_etm_recording, itr); > > + cs_etm_pmu = ptr->cs_etm_pmu; > > + > > + if (!cs_etm_is_etmv4(itr, cpu)) > > + goto out; > > + > > + /* 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) > > { > > @@ -118,6 +166,11 @@ static int cs_etm_set_option(struct auxtrace_record > > *itr, > > if (err) > > goto out; > > break; > > + case ETM_OPT_TS: > > + err = cs_etm_set_timestamp(itr, evsel, i); > > + if (err) > > + goto out; > > + break; > > default: > > goto out; > > } > > @@ -343,6 +396,10 @@ 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; > > nit: Could we not do this in one shot, say : > > cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_TS | ETM_OPT_CTXTID) ? > > rather than iterating over the per-CPU events twice ? The cs_etm_set_option() > could simply replace the switch() to : > > if (option & ETM_OPT_1) > do_something_for_1() > if (option & ETM_OPT_2) > do_something_for_2(); > if (option & ~(ETM_OPT_1 | ETM_OPT_2 |...)) > /* do unsupported option */ >
Yes, that is a good optimization. Arnaldo, do you prefer a new set or another patch on top of this one? Thanks, Mathieu > > Cheers > Suzuki
