RE: [RFC PATCH 00/25] Perf stat metric grouping with hardware information

Wang, Weilin
2023-09-26T20:40:22Z

> -----Original Message-----
> From: Ian Rogers <irogers@google.com>
> Sent: Monday, September 25, 2023 11:30 AM
> To: Wang, Weilin <weilin.wang@intel.com>
> Cc: Peter Zijlstra <peterz@infradead.org>; Ingo Molnar <mingo@redhat.com>;
> Arnaldo Carvalho de Melo <acme@kernel.org>; Alexander Shishkin
> <alexander.shishkin@linux.intel.com>; Jiri Olsa <jolsa@kernel.org>; Namhyung
> Kim <namhyung@kernel.org>; Hunter, Adrian <adrian.hunter@intel.com>;
> Kan Liang <kan.liang@linux.intel.com>; linux-perf-users@vger.kernel.org;
> linux-kernel@vger.kernel.org; Taylor, Perry <perry.taylor@intel.com>; Alt,
> Samantha <samantha.alt@intel.com>; Biggers, Caleb
> <caleb.biggers@intel.com>; Mark Rutland <mark.rutland@arm.com>
> Subject: Re: [RFC PATCH 00/25] Perf stat metric grouping with hardware
> information
>
> On Sun, Sep 24, 2023 at 11:19 PM <weilin.wang@intel.com> wrote:
> >
> > From: Weilin Wang <weilin.wang@intel.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 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.
>
> Thanks Weilin! I'm checking out the series. Hopefully the NMI watchdog perf
> event can go away soon with the buddy scheme:
> https://lore.kernel.org/lkml/20230527014153.2793931-1-
> dianders@chromium.org/
> But better NMI handling would be true for people without the latest kernel.
>
> Thanks,
> Ian
>
Thanks Ian! I will update the NMI handling in next version.

> > 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.
> > 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
> >