linux-kernel - Re: [PATCH v4 00/17] Compress the pmu

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Message-ID: <YvK4YUWRktOQBlfr@kernel.org>
Date:   Tue, 9 Aug 2022 16:41:21 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Ian Rogers <irogers@...gle.com>
Cc:     John Garry <john.garry@...wei.com>, Will Deacon <will@...nel.org>,
        James Clark <james.clark@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Leo Yan <leo.yan@...aro.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-perf-users@...r.kernel.org,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v4 00/17]  Compress the pmu_event tables

Em Tue, Aug 09, 2022 at 04:40:43PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Aug 04, 2022 at 03:17:59PM -0700, Ian Rogers escreveu:
> > jevents.py creates a number of large arrays from the json events. The
> > arrays contain pointers to strings that need relocating. The
> > relocations have file size, run time and memory costs. These changes
> > refactor the pmu_events API so that the storage of the pmu_event
> > struct isn't exposed. The format is then changed to an offset within a
> > combined big string, with adjacent pmu_event struct variables being
> > next to each other in the string separated by \0 - meaning only the
> > first variable of the struct needs its offset recording.
> > 
> > Some related fixes are contained with the patches. The architecture
> > jevents.py creates tables for can now be set by the JEVENTS_ARCH make
> > variable, with a new 'all' that generates the events and metrics for
> > all architectures.
> > 
> > An example of the improvement to the file size on x86 is:
> > no jevents - the same 19,788,464bytes
> > x86 jevents - ~16.7% file size saving 23,744,288bytes vs 28,502,632bytes
> > all jevents - ~19.5% file size saving 24,469,056bytes vs 30,379,920bytes
> > default build options plus NO_LIBBFD=1.
> 
> Applied the first four patches, waiting for the review comments to be

Sorry, three.

> discussed.
> 
> - Arnaldo
>  
> > I originally suggested fixing this problem in:
> > https://lore.kernel.org/linux-perf-users/CAP-5=fVB8G4bdb9T=FncRTh9oBVKCS=+=eowAO+YSgAhab+Dtg@mail.gmail.com/
> > 
> > v4. Fixed an issue with the empty-pmu-events.c spotted by John Garry
> >     <john.garry@...wei.com>.
> > v3. Fix an ARM build issue with a missed weak symbol. Perform some
> >     pytype clean up.
> > v2. Split the substring folding optimization to its own patch and
> >     comment tweaks as suggested by Namhyung Kim
> >     <namhyung@...nel.org>. Recompute the file size savings with the
> >     latest json events and metrics.
> > 
> > Ian Rogers (17):
> >   perf jevents: Clean up pytype warnings
> >   perf jevents: Simplify generation of C-string
> >   perf jevents: Add JEVENTS_ARCH make option
> >   perf jevent: Add an 'all' architecture argument
> >   perf jevents: Remove the type/version variables
> >   perf jevents: Provide path to json file on error
> >   perf jevents: Sort json files entries
> >   perf pmu-events: Hide pmu_sys_event_tables
> >   perf pmu-events: Avoid passing pmu_events_map
> >   perf pmu-events: Hide pmu_events_map
> >   perf test: Use full metric resolution
> >   perf pmu-events: Move test events/metrics to json
> >   perf pmu-events: Don't assume pmu_event is an array
> >   perf pmu-events: Hide the pmu_events
> >   perf metrics: Copy entire pmu_event in find metric
> >   perf jevents: Compress the pmu_events_table
> >   perf jevents: Fold strings optimization
> > 
> >  tools/perf/arch/arm64/util/pmu.c              |   4 +-
> >  tools/perf/pmu-events/Build                   |   6 +-
> >  .../arch/test/test_soc/cpu/metrics.json       |  64 +++
> >  tools/perf/pmu-events/empty-pmu-events.c      | 204 +++++++-
> >  tools/perf/pmu-events/jevents.py              | 495 ++++++++++++++----
> >  tools/perf/pmu-events/pmu-events.h            |  40 +-
> >  tools/perf/tests/expand-cgroup.c              |  25 +-
> >  tools/perf/tests/parse-metric.c               |  77 +--
> >  tools/perf/tests/pmu-events.c                 | 466 +++++++----------
> >  tools/perf/util/metricgroup.c                 | 275 ++++++----
> >  tools/perf/util/metricgroup.h                 |   5 +-
> >  tools/perf/util/pmu.c                         | 139 ++---
> >  tools/perf/util/pmu.h                         |   8 +-
> >  tools/perf/util/s390-sample-raw.c             |  50 +-
> >  14 files changed, 1140 insertions(+), 718 deletions(-)
> >  create mode 100644 tools/perf/pmu-events/arch/test/test_soc/cpu/metrics.json
> > 
> > -- 
> > 2.37.1.559.g78731f0fdb-goog
> 
> -- 
> 
> - Arnaldo

-- 

- Arnaldo