Re: [PATCH v3 0/3] Rewrite jevents program in python

[John Garry]

On 27/05/2022 19:54, Ian Rogers wrote:
> New architectures bring new complexity, such as Intel's hybrid
> models. jevents provides an alternative to specifying events in the
> kernel and exposing them through sysfs, however, it is difficult to
> work with. For example, an error in the json input would yield an
> error message but no json file or location. It is also a challenge to
> update jsmn.c given its forked nature.
>
> The changes here switch from jevents.c to a rewrite in python called
> jevents.py. This means there is a build time dependency on python, but
> such a dependency already exists for asciidoc (used to generate perf's
> man pages). If the build detects that python isn't present or is older
> than version 3.6 (released Dec. 2016) then an empty file is
> substituted for the generated one.
>
> A challenge with this code is in avoiding regressions. For this reason
> the jevents.py produces identical output to jevents.c, validated with a
> test script and build target.

Hi Ian,

I still see this:

...
Makefile.config:906: Python interpreter too old (older than 3.6) 
disabling jevent generation
Makefile.config:939: Old version of libbfd/binutils things like PE 
executable profiling will not be available
Makefile.config:1127: No openjdk development package found, please 
install JDK package, e.g. openjdk-8-jdk, java-1.8.0-openjdk-devel

Auto-detecting system features:
...                         dwarf: [ on  ]
...            dwarf_getlocations: [ on  ]
...                         glibc: [ on  ]
...                        libbfd: [ OFF ]
...                libbfd-buildid: [ OFF ]
...                        libcap: [ on  ]
...                        libelf: [ on  ]
...                       libnuma: [ on  ]
...        numa_num_possible_cpus: [ on  ]
...                       libperl: [ on  ]
...                     libpython: [ on  ]
...                     libcrypto: [ on  ]
...                     libunwind: [ on  ]
...            libdw-dwarf-unwind: [ on  ]
...                          zlib: [ on  ]
...                          lzma: [ on  ]
...                     get_cpuid: [ on  ]
...                           bpf: [ on  ]
...                        libaio: [ on  ]
...                       libzstd: [ on  ]
...        disassembler-four-args: [ on  ]


make[3]: Nothing to be done for 'install_headers'.
john@localhost:~/acme/tools/perf> python --version
Python 3.6.12

I need to figure out what is going wrong...

Thanks,
John

> v3. Updates the patches for merged changes (on
>      acme/tmp.perf/core). Re-runs all comparisons to make sure the
>      generated pmu-events.c isn't altered at all by this change. Adds
>      the jevents.c ExtSel fix in:
>      https://lore.kernel.org/lkml/20220525140410.1706851-1-zhengjun.xing@xxxxxxxxxxxxxxx/
>      Bumps the python version from 3.5 to 3.6, as f-strings weren't
>      introduced until 3.6.
>
> v2. Fixes the build for architectures that don't have pmu-events json
>      (Suggested-by: John Garry <john.garry@xxxxxxxxxx>) and fixes the
>      build for python not being present or too old (Suggested-by: Peter
>      Zijlstra <peterz@xxxxxxxxxxxxx>/John Garry <john.garry@xxxxxxxxxx>).
>
> Ian Rogers (3):
>    perf jevents: Add python converter script
>    perf jevents: Switch build to use jevents.py
>    perf jevents: Remove jevents.c
>
>   tools/perf/Makefile.config               |   19 +
>   tools/perf/Makefile.perf                 |   16 +-
>   tools/perf/pmu-events/Build              |   15 +-
>   tools/perf/pmu-events/empty-pmu-events.c |   21 +
>   tools/perf/pmu-events/jevents.c          | 1342 ----------------------
>   tools/perf/pmu-events/jevents.py         |  392 +++++++
>   tools/perf/pmu-events/jsmn.h             |   68 --
>   tools/perf/pmu-events/json.c             |  162 ---
>   tools/perf/pmu-events/json.h             |   39 -
>   9 files changed, 444 insertions(+), 1630 deletions(-)
>   create mode 100644 tools/perf/pmu-events/empty-pmu-events.c
>   delete mode 100644 tools/perf/pmu-events/jevents.c
>   create mode 100755 tools/perf/pmu-events/jevents.py
>   delete mode 100644 tools/perf/pmu-events/jsmn.h
>   delete mode 100644 tools/perf/pmu-events/json.c
>   delete mode 100644 tools/perf/pmu-events/json.h