Messages in this thread Patch in this message | | | Date | Mon, 11 Jan 2021 21:12:05 +0800 | From | Leo Yan <> | Subject | Re: [PATCH v1 4/7] perf cs-etm: Add PID format into metadata |
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On Mon, Jan 11, 2021 at 09:45:12AM +0000, Suzuki Kuruppassery Poulose wrote: > Hi Leo, > > On 1/9/21 7:44 AM, Leo Yan wrote: > > It's possible for CoreSight to trace PID in either CONTEXTIDR_EL1 or > > CONTEXTIDR_EL2, the PID format info is used to distinguish the PID > > is traced in which register. > > > > This patch saves PID format into the metadata when record. > > The patch looks good to me. One minor suggestion below > > > > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > > --- > > tools/perf/arch/arm/util/cs-etm.c | 21 +++++++++++++++++++++ > > tools/perf/util/cs-etm.c | 2 ++ > > tools/perf/util/cs-etm.h | 2 ++ > > 3 files changed, 25 insertions(+) > > > > diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c > > index fad7b6e13ccc..ee78df3b1b07 100644 > > --- a/tools/perf/arch/arm/util/cs-etm.c > > +++ b/tools/perf/arch/arm/util/cs-etm.c > > @@ -613,6 +613,7 @@ static void cs_etm_get_metadata(int cpu, u32 *offset, > > struct cs_etm_recording *ptr = > > container_of(itr, struct cs_etm_recording, itr); > > struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu; > > + u64 pid_fmt; > > /* first see what kind of tracer this cpu is affined to */ > > if (cs_etm_is_etmv4(itr, cpu)) { > > @@ -641,6 +642,16 @@ static void cs_etm_get_metadata(int cpu, u32 *offset, > > metadata_etmv4_ro > > [CS_ETMV4_TRCAUTHSTATUS]); > > + /* > > + * The PID format will be used when decode the trace data; > > + * based on it the decoder will make decision for setting > > + * sample's PID as context_id or VMID. > > + */ > > + pid_fmt = perf_pmu__format_bits(&cs_etm_pmu->format, "pid"); > > + if (!pid_fmt) > > + pid_fmt = 1ULL << ETM_OPT_CTXTID; > > + info->priv[*offset + CS_ETMV4_PID_FMT] = pid_fmt; > > + > > Given we do this same step twice here in this function and also in patch 2. > I am wondering if this could be made into a small helper function ? > > static u64 cs_etm_pmu_format_pid(cs_etm_pm) > { > pid_fmt = perf_pmu__format_bits(&cs_etm_pmu->format, "pid"); > /* > * An older kernel doesn't expose this, so fall back to using > * CTXTID. > */ > if (!pid_fmt) > pid_fmt = 1ULL << ETM_OPT_CTXTID; > return pid_fmt; > }
Agreed; will follow up this suggestion.
Thanks, Leo
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