Messages in this thread | | | From | Ian Rogers <> | Date | Tue, 12 Dec 2023 12:37:12 -0800 | Subject | Re: [PATCH V2] perf top: Use evsel's cpus to replace user_requested_cpus |
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On Tue, Dec 12, 2023 at 11:39 AM <kan.liang@linux.intel.com> wrote: > > From: Kan Liang <kan.liang@linux.intel.com> > > perf top errors out on a hybrid machine > $perf top > > Error: > The cycles:P event is not supported. > > The perf top expects that the "cycles" is collected on all CPUs in the > system. But for hybrid there is no single "cycles" event which can cover > all CPUs. Perf has to split it into two cycles events, e.g., > cpu_core/cycles/ and cpu_atom/cycles/. Each event has its own CPU mask. > If a event is opened on the unsupported CPU. The open fails. That's the > reason of the above error out. > > Perf should only open the cycles event on the corresponding CPU. The > commit ef91871c960e ("perf evlist: Propagate user CPU maps intersecting > core PMU maps") intersect the requested CPU map with the CPU map of the > PMU. Use the evsel's cpus to replace user_requested_cpus. > > The evlist's threads are also propagated to the evsel's threads in > __perf_evlist__propagate_maps(). For a system-wide event, perf appends > a dummy event and assign it to the evsel's threads. For a per-thread > event, the evlist's thread_map is assigned to the evsel's threads. The > same as the other tools, e.g., perf record, using the evsel's threads > when opening an event. > > Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org> > Closes: https://lore.kernel.org/linux-perf-users/ZXNnDrGKXbEELMXV@kernel.org/ > Reviewed-by: Ian Rogers <irogers@google.com> > Signed-off-by: Kan Liang <kan.liang@linux.intel.com> > --- > > Changes since V1: > - Update the description > - Add Reviewed-by from Ian
Thanks Kan, quick question. Does "perf top" on hybrid ask the user to select between the cycles event on cpu_atom and cpu_core? I'm wondering if there is some kind of missing "hybrid-merge" functionality like we have for perf stat.
Thanks, Ian
> tools/perf/builtin-top.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c > index ea8c7eca5eee..cce9350177e2 100644 > --- a/tools/perf/builtin-top.c > +++ b/tools/perf/builtin-top.c > @@ -1027,8 +1027,8 @@ static int perf_top__start_counters(struct perf_top *top) > > evlist__for_each_entry(evlist, counter) { > try_again: > - if (evsel__open(counter, top->evlist->core.user_requested_cpus, > - top->evlist->core.threads) < 0) { > + if (evsel__open(counter, counter->core.cpus, > + counter->core.threads) < 0) { > > /* > * Specially handle overwrite fall back. > -- > 2.35.1 >
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