Messages in this thread | | | From | Ian Rogers <> | Date | Sat, 10 Jun 2023 20:55:13 -0700 | Subject | Re: [PATCH v5 28/34] perf pmus: Split pmus list into core and other |
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On Fri, Jun 9, 2023 at 12:59 AM Mark Rutland <mark.rutland@arm.com> wrote: > > On Thu, Jun 08, 2023 at 10:35:02PM -0700, Ian Rogers wrote: > > On Thu, Jun 8, 2023 at 10:30 PM Ravi Bangoria <ravi.bangoria@amd.com> wrote: > > > > > > On 09-Jun-23 10:10 AM, Ian Rogers wrote: > > > > On Thu, Jun 8, 2023 at 9:01 PM Ravi Bangoria <ravi.bangoria@amd.com> wrote: > > > >> > > > >> Hi Ian, > > > > > > > > Hi Ravi, > > > > > > > >> On 27-May-23 12:52 PM, Ian Rogers wrote: > > > >>> Split the pmus list into core and other. This will later allow for > > > >>> the core and other pmus to be populated separately. > > > >>> > > > >>> Signed-off-by: Ian Rogers <irogers@google.com> > > > >>> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> > > > >>> --- > > > >>> tools/perf/util/pmus.c | 52 ++++++++++++++++++++++++++++++------------ > > > >>> 1 file changed, 38 insertions(+), 14 deletions(-) > > > >>> > > > >>> diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c > > > >>> index 58ff7937e9b7..4ef4fecd335f 100644 > > > >>> --- a/tools/perf/util/pmus.c > > > >>> +++ b/tools/perf/util/pmus.c > > > >>> @@ -12,13 +12,19 @@ > > > >>> #include "pmu.h" > > > >>> #include "print-events.h" > > > >>> > > > >>> -static LIST_HEAD(pmus); > > > >>> +static LIST_HEAD(core_pmus); > > > >>> +static LIST_HEAD(other_pmus); > > > >> > > > >> AMD ibs_fetch// and ibs_op// PMUs are per SMT-thread and are independent of > > > >> core hw pmu. I wonder where does IBS fit. Currently it's part of other_pmus. > > > >> So, is it safe to assume that other_pmus are not just uncore pmus? In that > > > >> case shall we add a comment here? > > > > > > > > I'm a fan of comments. The code has landed in perf-tools-next: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/pmus.c?h=perf-tools-next > > > > Do you have any suggestions on wording? I've had limited success > > > > adding glossary terms, for example, offcore vs uncore: > > > > https://perf.wiki.kernel.org/index.php/Glossary#Offcore > > > > I think offcore is a more interconnect related term, but I'd prefer > > > > not to be inventing the definitions. I'd like it if we could be less > > > > ambiguous in the code and provide useful information on the wiki, so > > > > help appreciated :-) > > > > > > Does this look good? > > > > > > /* > > > * core_pmus: A PMU belongs to core_pmus if it's name is "cpu" or it's sysfs > > > * directory contains "cpus" file. All PMUs belonging to core_pmus > > > * must have pmu->is_core=1. If there are more than one PMUs in > > > * this list, perf interprets it as a heterogeneous platform. > > > > > > Looks good but a nit here. It is heterogeneous from point-of-view of > > PMUs, there are ARM systems where they are heterogenous with big and > > little cores but they have a single homogeneous PMU driver. The perf > > tool will treat them as homogeneous. > > For the sake of the comment: there's a little more nuance here. > > The intent is that each distinct micro-architecture has its own PMU instance, > but some people write their device trees incorrectly with a single pmu node > rather than separate pmu nodes per micro-architecture. > > That should be viewed as a FW bug, even if we have to deal with it here.
Thanks for the clarification Mark. For heterogeneous ARM I was primarily looking at a Pixel 4 phone, which has a homogeneous PMU. The normal way to make sure Android configurations are sensible is to have a CTS test. Would that be appropriate here?
Given Intel contributed the original heterogeneous PMU support to the perf tool, and hard coded the PMU names to 'cpu_core' and 'cpu_atom', are there any correctness tests that exist for ARM heterogeneous PMUs? Could we make this part of the 'perf test' command? Tests acting both as a correctness feature and documentation.
Thanks, Ian
> Thanks, > Mark.
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