Re: [PATCH v6 0/4] Rewrite jevents program in python

[Xing Zhengjun <zhengjun.xing@linux.intel.com>]

Hi Ian,

On 6/18/2022 9:41 AM, Ian Rogers wrote:
> On Fri, Jun 17, 2022 at 5:23 PM Xing Zhengjun
> <zhengjun.xing@linux.intel.com> wrote:
>>
>> Hi Ian,
>>
>> On 6/18/2022 8:09 AM, 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.
>>>
>>> v6. Fixes an annotation and use of removesuffix that aren't present in
>>>       Python 3.6. Linter issues are also fixed.The code was tested on
>>>       Python 3.6 and 3.8 with docker.
>>
>> I just test it, now it can be built successfully with python 3.8.
> 
> Great! Tested-by/Reviewed-by/Acked-by always welcome :-)

I test python3.8 and python3.10, both can build successfully.
I also check the "pmu-events.c" generated by both C and python code, 
they are the same.

Tested-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>

> 
> Ian
> 
>>> v5. Adds a 2>/dev/null as suggested by David Laight
>>>       <David.Laight@aculab.com>.
>>> v4. Fixes the build for systems with python2 installed by adding a
>>>       patch that makes python3 the preferred python (Reported-by: John
>>>       Garry <john.garry@huawei.com>). It also fixes a bash-ism in the
>>>       jevents-test.sh and fixes the handling of an empty string for a
>>>       metric BriefDescription as one was added for sapphirerapids in the
>>>       metric Execute.
>>> 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@linux.intel.com/
>>>       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@huawei.com>) and fixes the
>>>       build for python not being present or too old (Suggested-by: Peter
>>>       Zijlstra <peterz@infradead.org>/John Garry <john.garry@huawei.com>).
>>>
>>> Ian Rogers (4):
>>>     perf python: Prefer python3
>>>     perf jevents: Add python converter script
>>>     perf jevents: Switch build to use jevents.py
>>>     perf jevents: Remove jevents.c
>>>
>>>    tools/perf/Makefile.config               |   27 +-
>>>    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         |  409 +++++++
>>>    tools/perf/pmu-events/jsmn.h             |   68 --
>>>    tools/perf/pmu-events/json.c             |  162 ---
>>>    tools/perf/pmu-events/json.h             |   39 -
>>>    9 files changed, 465 insertions(+), 1634 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
>>>
>>
>> --
>> Zhengjun Xing

-- 
Zhengjun Xing