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Date: Tue, 26 Sep 2023 12:48:41 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: weilin.wang@...el.com, Ian Rogers <irogers@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>
Cc: linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Perry Taylor <perry.taylor@...el.com>,
Samantha Alt <samantha.alt@...el.com>,
Caleb Biggers <caleb.biggers@...el.com>,
Mark Rutland <mark.rutland@....com>
Subject: Re: [RFC PATCH 00/25] Perf stat metric grouping with hardware
information
On 2023-09-26 10:43 a.m., Liang, Kan wrote:
>
>
> On 2023-09-25 2:17 a.m., weilin.wang@...el.com wrote:
>> From: Weilin Wang <weilin.wang@...el.com>
>>
>> Perf stat metric grouping generates event groups that are provided to kernel for
>> data collection using the hardware counters. Sometimes, the grouping might fail
>> and kernel has to retry the groups because generated groups do not fit in the
>> hardware counters correctly. In some other cases, the groupings are collected
>> correctly, however, they left some hardware counters unused.
>>
>> To improve these inefficiencies, we would like to propose a hardware aware
>> grouping method that does metric/event grouping based on event counter>> restriction rules and the availability of hardware counters in the
system. This
>> method is generic as long as all the restriction rules could be provided from
>> the pmu-event JSON files.
>
> This method assumes that it's the only user (expect NMI watchdog) and
> all the HW resource are available. Right?
It's better to give more details about the algorithm of the method. How
to decide to create a new group? How to decide which group the event
will be added into. etc.
Thanks,
Kan
>
>>
>> This patch set includes code that does hardware aware grouping and updated
>> pmu-event JSON files for four platforms (SapphireRapids, Icelakex, Cascadelakex,
>> and Tigerlake) for your testing and experimenting. We've successfully tested
>> these patches on three platforms (SapphireRapids, Icelakex, and Cascadelakex)
>> with topdown metrics from TopdownL1 to TopdownL6.
>>
>> There are some optimization opportunities that we might implement in the future:
>> 1) Better NMI hanlding: when NMI watchdog is enabled, we reduce the default_core
>> total counter size by one. This could be improved to better utilize the counter.
>> 2) Fill important events into unused counter for better counter utlization:
>> there might be some unused counters scattered in the groups. We could consider
>> to add important events in this slots if necessary. This could help increase the
>> multiplexing percentage and help improve accuracy if the event is critical.
>>
>> Remaining questions for dicussion:
>> 3) Where to start grouping from? The current implementation start grouping by
>> combining all the events into a single list. This step deduplicates events. But
>> it does not maintain the relationship of events according to the metrics, i.e.
>> events required by one metric may not be collected at the same time. Another
>> type of starting point would be grouping each individual metric and then try to
>> merge the groups.
>
> Maybe you can add a new flag to tag the metric which should/better be
> scheduled together, e.g., IPC.
>
> Thanks,
> Kan
>> 4) Any comments, suggestions, new ideas?
>> 5) If you are interested to test the patch out and the pmu-event JSON files of
>> your testing platform is not provided here, please let me know so that I could
>> provide you the files.
>>
>>
>> Weilin Wang (25):
>> perf stat: Add hardware-grouping cmd option to perf stat
>> perf stat: Add basic functions for the hardware-grouping stat cmd
>> option
>> perf pmu-events: Add functions in jevent.py
>> perf pmu-events: Add counter info into JSON files for SapphireRapids
>> perf pmu-events: Add event counter data for Cascadelakex
>> perf pmu-events: Add event counter data for Icelakex
>> perf stat: Add helper functions for hardware-grouping method
>> perf stat: Add functions to get counter info
>> perf stat: Add helper functions for hardware-grouping method
>> perf stat: Add helper functions to hardware-grouping method
>> perf stat: Add utility functions to hardware-grouping method
>> perf stat: Add more functions for hardware-grouping method
>> perf stat: Add functions to hardware-grouping method
>> perf stat: Add build string function and topdown events handling in
>> hardware-grouping
>> perf stat: Add function to combine metrics for hardware-grouping
>> perf stat: Update keyword core to default_core to adjust to the
>> changes for events with no unit
>> perf stat: Handle taken alone in hardware-grouping
>> perf stat: Handle NMI in hardware-grouping
>> perf stat: Handle grouping method fall back in hardware-grouping
>> perf stat: Code refactoring in hardware-grouping
>> perf stat: Add tool events support in hardware-grouping
>> perf stat: Add TSC support in hardware-grouping
>> perf stat: Fix a return error issue in hardware-grouping
>> perf stat: Add check to ensure correctness in platform that does not
>> support hardware-grouping
>> perf pmu-events: Add event counter data for Tigerlake
>>
>> tools/lib/bitmap.c | 20 +
>> tools/perf/builtin-stat.c | 7 +
>> .../arch/x86/cascadelakex/cache.json | 1237 ++++++++++++
>> .../arch/x86/cascadelakex/counter.json | 17 +
>> .../arch/x86/cascadelakex/floating-point.json | 16 +
>> .../arch/x86/cascadelakex/frontend.json | 68 +
>> .../arch/x86/cascadelakex/memory.json | 751 ++++++++
>> .../arch/x86/cascadelakex/other.json | 168 ++
>> .../arch/x86/cascadelakex/pipeline.json | 102 +
>> .../arch/x86/cascadelakex/uncore-cache.json | 1138 +++++++++++
>> .../x86/cascadelakex/uncore-interconnect.json | 1272 +++++++++++++
>> .../arch/x86/cascadelakex/uncore-io.json | 394 ++++
>> .../arch/x86/cascadelakex/uncore-memory.json | 509 +++++
>> .../arch/x86/cascadelakex/uncore-power.json | 25 +
>> .../arch/x86/cascadelakex/virtual-memory.json | 28 +
>> .../pmu-events/arch/x86/icelakex/cache.json | 98 +
>> .../pmu-events/arch/x86/icelakex/counter.json | 17 +
>> .../arch/x86/icelakex/floating-point.json | 13 +
>> .../arch/x86/icelakex/frontend.json | 55 +
>> .../pmu-events/arch/x86/icelakex/memory.json | 53 +
>> .../pmu-events/arch/x86/icelakex/other.json | 52 +
>> .../arch/x86/icelakex/pipeline.json | 92 +
>> .../arch/x86/icelakex/uncore-cache.json | 965 ++++++++++
>> .../x86/icelakex/uncore-interconnect.json | 1667 +++++++++++++++++
>> .../arch/x86/icelakex/uncore-io.json | 966 ++++++++++
>> .../arch/x86/icelakex/uncore-memory.json | 186 ++
>> .../arch/x86/icelakex/uncore-power.json | 26 +
>> .../arch/x86/icelakex/virtual-memory.json | 22 +
>> .../arch/x86/sapphirerapids/cache.json | 104 +
>> .../arch/x86/sapphirerapids/counter.json | 17 +
>> .../x86/sapphirerapids/floating-point.json | 25 +
>> .../arch/x86/sapphirerapids/frontend.json | 98 +-
>> .../arch/x86/sapphirerapids/memory.json | 44 +
>> .../arch/x86/sapphirerapids/other.json | 40 +
>> .../arch/x86/sapphirerapids/pipeline.json | 118 ++
>> .../arch/x86/sapphirerapids/uncore-cache.json | 534 +++++-
>> .../arch/x86/sapphirerapids/uncore-cxl.json | 56 +
>> .../sapphirerapids/uncore-interconnect.json | 476 +++++
>> .../arch/x86/sapphirerapids/uncore-io.json | 373 ++++
>> .../x86/sapphirerapids/uncore-memory.json | 391 ++++
>> .../arch/x86/sapphirerapids/uncore-power.json | 24 +
>> .../x86/sapphirerapids/virtual-memory.json | 20 +
>> .../pmu-events/arch/x86/tigerlake/cache.json | 65 +
>> .../arch/x86/tigerlake/counter.json | 7 +
>> .../arch/x86/tigerlake/floating-point.json | 13 +
>> .../arch/x86/tigerlake/frontend.json | 56 +
>> .../pmu-events/arch/x86/tigerlake/memory.json | 31 +
>> .../pmu-events/arch/x86/tigerlake/other.json | 4 +
>> .../arch/x86/tigerlake/pipeline.json | 96 +
>> .../x86/tigerlake/uncore-interconnect.json | 11 +
>> .../arch/x86/tigerlake/uncore-memory.json | 6 +
>> .../arch/x86/tigerlake/uncore-other.json | 1 +
>> .../arch/x86/tigerlake/virtual-memory.json | 20 +
>> tools/perf/pmu-events/jevents.py | 179 +-
>> tools/perf/pmu-events/pmu-events.h | 26 +-
>> tools/perf/util/metricgroup.c | 927 +++++++++
>> tools/perf/util/metricgroup.h | 82 +
>> tools/perf/util/pmu.c | 5 +
>> tools/perf/util/pmu.h | 1 +
>> tools/perf/util/stat.h | 1 +
>> 60 files changed, 13790 insertions(+), 25 deletions(-)
>> create mode 100644 tools/perf/pmu-events/arch/x86/cascadelakex/counter.json
>> create mode 100644 tools/perf/pmu-events/arch/x86/icelakex/counter.json
>> create mode 100644 tools/perf/pmu-events/arch/x86/sapphirerapids/counter.json
>> create mode 100644 tools/perf/pmu-events/arch/x86/tigerlake/counter.json
>>
>> --
>> 2.39.3
>>
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