[PATCH v3 00/17] Compress the pmu_event tables

From: Ian Rogers
Date: Fri Jul 29 2022 - 03:44:06 EST


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.

I originally suggested fixing this problem in:
https://lore.kernel.org/linux-perf-users/CAP-5=fVB8G4bdb9T=FncRTh9oBVKCS=+=eowAO+YSgAhab+Dtg@xxxxxxxxxxxxxx/

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

--
2.37.1.455.g008518b4e5-goog