Re: [PATCH v4 00/17] Compress the pmu_event tables

[Arnaldo Carvalho de Melo]

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
discussed.

- Arnaldo
 
> I originally suggested fixing this problem in:
> https://lore.kernel.org/linux-perf-users/CAP-5=fVB8G4bdb9T=FncRTh9oBVKCS=+=eowAO+YSgAhab+Dtg@xxxxxxxxxxxxxx/
> 
> v4. Fixed an issue with the empty-pmu-events.c spotted by John Garry
>     <john.garry@xxxxxxxxxx>.
> 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@xxxxxxxxxx>. 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