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Message-ID: <961ff6d6-a9b3-4329-9a22-6934ca152318@linux.intel.com> Date: Thu, 22 Aug 2024 11:18:45 -0400 From: "Liang, Kan" <kan.liang@...ux.intel.com> To: Ian Rogers <irogers@...gle.com> Cc: James Clark <james.clark@...aro.org>, linux-perf-users@...r.kernel.org, John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>, Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...ux.dev>, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>, Weilin Wang <weilin.wang@...el.com>, Athira Rajeev <atrajeev@...ux.vnet.ibm.com>, Dominique Martinet <asmadeus@...ewreck.org>, Yang Jihong <yangjihong@...edance.com>, Colin Ian King <colin.i.king@...il.com>, Andi Kleen <ak@...ux.intel.com>, Ze Gao <zegao2021@...il.com>, Jing Zhang <renyu.zj@...ux.alibaba.com>, Sun Haiyong <sunhaiyong@...ngson.cn>, Yicong Yang <yangyicong@...ilicon.com>, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v4 0/7] Event parsing fixes On 2024-08-22 11:10 a.m., Ian Rogers wrote: > On Thu, Aug 22, 2024 at 7:32 AM Liang, Kan <kan.liang@...ux.intel.com> wrote: >> >> >> >> On 2024-08-22 9:24 a.m., James Clark wrote: >>> I rebased this one and made some other fixes so that I could test it, >>> so I thought I'd repost it here in case it's helpful. I also added a >>> new test. >>> >>> But for the testing it all looks ok. >>> >>> There is one small difference where it now shows "stalled-cycles-..." >>> as <not supported> events, when before it just didn't show them at all when >>> they weren't supported: >>> >>> $ perf stat -- true >>> >>> Performance counter stats for 'true': >>> >>> 0.66 msec task-clock # 0.384 CPUs utilized >>> 0 context-switches # 0.000 /sec >>> 0 cpu-migrations # 0.000 /sec >>> 52 page-faults # 78.999 K/sec >>> <not counted> cpu_atom/instructions/ (0.00%) >>> 978,399 cpu_core/instructions/ # 1.02 insn per cycle >>> <not counted> cpu_atom/cycles/ (0.00%) >>> 959,722 cpu_core/cycles/ # 1.458 GHz >>> <not supported> cpu_atom/stalled-cycles-frontend/ >>> <not supported> cpu_core/stalled-cycles-frontend/ >>> >> >> Intel didn't support the events for a very long time. It would impact >> many existing generations and all future generations. >> The current method is to hide the non-exist events. The TopdownL1 is an >> example. If it doesn't exist in the json file, perf stat will not >> display it. >> I don't think it's a good idea to disclose non-exist events in the perf >> stat default. >> >> The <not supported> doesn't help here, since there could be many reasons >> that the perf tool fails to open a counter. It just provides a >> misleading message for an event that never existed. > > The list of "default" events, not metrics, similarly has "<not > supported>" in many configurations with "-dd" or "-ddd" on AMD. I'm > not sure the set of default events, at different detail levels, is > necessarily the best. The default events can also be a source of > multiplexing, for example, showing branch miss rate alongside topdown > metrics. Anyway, for the "<not supported>" we should probably be able > to tweak should_skip_zero_counter that is in stat-display.c and tag > these default events as "skippable". The "skippable" should be fine as long as it's completely hidden. BTW: The stalled-cycles-backend should be similar to the stalled-cycles-frontend, but it isn't shown in the example. Is the stalled-cycles-backend event missed? Thanks, Kan > > Thanks, > Ian > >> Thanks, >> Kan >>> I don't think that's a big deal though and could probably be fixed up >>> later if we really want to. >>> >>> Tested on Raptor Lake, Juno, N1, Ampere (with the DSU cycles PMU) and >>> I also faked an Apple M on Juno. >>> >>> Changes since v3: >>> >>> * Rebase onto perf-tools-next 6236ebe07 >>> * Fix Intel TPEBS counting mode test >>> * Fix arm-spe build >>> * Add support for DT devices in stat test >>> * Add a new test for hybrid perf stat default arguments >>> >>> Ian Rogers (5): >>> perf evsel: Add alternate_hw_config and use in evsel__match >>> perf stat: Uniquify event name improvements >>> perf stat: Remove evlist__add_default_attrs use strings >>> perf evsel x86: Make evsel__has_perf_metrics work for legacy events >>> perf evsel: Remove pmu_name >>> >>> James Clark (2): >>> perf test: Make stat test work on DT devices >>> perf test: Add a test for default perf stat command >>> >>> tools/perf/arch/arm64/util/arm-spe.c | 4 +- >>> tools/perf/arch/x86/util/evlist.c | 74 +---- >>> tools/perf/arch/x86/util/evsel.c | 35 ++- >>> tools/perf/builtin-diff.c | 6 +- >>> tools/perf/builtin-stat.c | 291 +++++++----------- >>> tools/perf/tests/parse-events.c | 2 +- >>> tools/perf/tests/shell/stat.sh | 33 +- >>> .../perf/tests/shell/test_stat_intel_tpebs.sh | 11 +- >>> tools/perf/util/evlist.c | 46 +-- >>> tools/perf/util/evlist.h | 12 - >>> tools/perf/util/evsel.c | 28 +- >>> tools/perf/util/evsel.h | 22 +- >>> tools/perf/util/metricgroup.c | 4 +- >>> tools/perf/util/parse-events.c | 58 ++-- >>> tools/perf/util/parse-events.h | 8 +- >>> tools/perf/util/parse-events.y | 2 +- >>> tools/perf/util/pmu.c | 6 +- >>> tools/perf/util/pmu.h | 2 +- >>> tools/perf/util/stat-display.c | 101 ++++-- >>> tools/perf/util/stat-shadow.c | 14 +- >>> tools/perf/util/stat.c | 2 +- >>> 21 files changed, 348 insertions(+), 413 deletions(-) >>> >
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