Messages in this thread | | | From | Ian Rogers <> | Date | Tue, 11 Jul 2023 22:40:08 -0700 | Subject | Re: [PATCH RFC 2/9] perf metrics: Don't iter sys metrics if we already found a CPU match |
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On Mon, Jul 3, 2023 at 6:09 AM John Garry <john.g.garry@oracle.com> wrote: > > On 30/06/2023 18:41, Ian Rogers wrote: > > On Wed, Jun 28, 2023 at 3:30 AM John Garry<john.g.garry@oracle.com> wrote: > >> In metricgroup__add_metric() we still iter the sys metrics if we already > >> found a match from the CPU table, which is pretty pointless, so don't > >> bother. > >> > >> Signed-off-by: John Garry<john.g.garry@oracle.com> > >> --- > >> tools/perf/util/metricgroup.c | 7 +++++++ > >> 1 file changed, 7 insertions(+) > >> > >> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c > >> index 4389ccd29fe7..8d2ac2513530 100644 > >> --- a/tools/perf/util/metricgroup.c > >> +++ b/tools/perf/util/metricgroup.c > >> @@ -1261,6 +1261,12 @@ static int metricgroup__add_metric(const char *pmu, const char *metric_name, con > >> > >> has_match = data.has_match; > >> } > > Hi Ian, > > >> + > >> + if (has_match) { > >> + ret = 0; > >> + goto out; > >> + } > >> + > > I think this can just be: > > > > if (!has_match) > > But ret has no initial value > > > > > However, I'm not sure I agree with the intent of the change. We may > > have a metric like IPC and want it to apply to all types of CPU, GPU, > > etc. If we short-cut here then that won't be possible. > > A few points to make on this: > - Currently we don't have any same-named metrics like this, so not much > use in supporting it in the code (yet).
We have same named metrics for heterogeneous CPU PMUs: https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/pmu-events/arch/x86/alderlake/adl-metrics.json?h=perf-tools-next#n304 cpu_atom https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/pmu-events/arch/x86/alderlake/adl-metrics.json?h=perf-tools-next#n1125 cpu_core
> - Even if we had some same-named metrics, I am not sure if it even works > properly. Do we have any uncore PMU metrics which have same name as CPU > metrics?
So I was thinking IPC was a generic concept that would apply to a co-processor on a network card, a GPU, etc.
> - Further to the previous point, do we really want same-named metrics > for different PMUs in the future? I think event / metric names need to > be chosen carefully to avoid clash for other PMUs or keywords. For your > example, if I did ask for IPC metric, I'd like to be able to just know > I'm getting IPC metric for CPUs or some other PMUs, but not both.
At the moment if you request an event without a PMU, say instructions retired, we will attempt to open the event on every PMU - legacy events (PERF_TYPE_HARDWARE, PERF_TYPE_HW_CACHE) only try the core PMUs. It would seem consistent if metrics tried to open on every PMU like most events.
Thanks, Ian
> Thanks, > John > > >
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