Messages in this thread | | | Date | Fri, 9 Jul 2021 09:51:31 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf record: Add a dummy event for a hybrid system |
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Em Thu, Jul 08, 2021 at 10:32:13PM -0700, Namhyung Kim escreveu: > On Thu, Jul 8, 2021 at 9:05 AM <kan.liang@intel.com> wrote: > > > > From: Kan Liang <kan.liang@linux.intel.com> > > > > Some symbols may not be resolved if a user only monitor one type of PMU. > > > > $ sudo perf record -e cpu_atom/branch-instructions/ ./big_small_workload > > $ sudo perf report –stdio > > # Overhead Command Shared Object Symbol > > # ........ ......... ................. > > # ...................................... > > # > > 28.02% perf-exec [unknown] [.] 0x0000000000401cf6 > > 11.32% perf-exec [unknown] [.] 0x0000000000401d04 > > 10.90% perf-exec [unknown] [.] 0x0000000000401d11 > > 10.61% perf-exec [unknown] [.] 0x0000000000401cfc > > > > To parse symbols, the side-band events, e.g., COMM, which are generated > > by the kernel are required. To decide whether to generate the side-band > > event, the kernel relies on the event_filter_match() to filter the > > unrelated events. On a hybrid system, the event_filter_match() further > > checks the CPU mask of the current enabled PMU. If an event is collected > > on the CPU which doesn't have an enabled PMU, it's treated as an > > unrelated event. > > > > The "big_small_workload" is created in a big core, but runs on a small > > core. The side-band events are filtered, because the user only monitors > > the PMU of the small core. The big core PMU is not enabled. > > > > For a hybrid system, a dummy event is required to generate the complete > > side-band events. > > > > Signed-off-by: Kan Liang <kan.liang@linux.intel.com> > > Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks, applied.
- Arnaldo
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