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

[Jiri Olsa <olsajiri@gmail.com>]

On Fri, Jun 17, 2022 at 05:09:03PM -0700, 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.

hi,
I'm getting test failures with this:

 10: PMU events                                                      :
 10.1: PMU event table sanity                                        : FAILED!
 10.2: PMU event map aliases                                         : FAILED!
 10.3: Parsing of PMU event table metrics                            : Ok
 10.4: Parsing of PMU event table metrics with fake PMUs             : Ok

I can see that pass without the patchset, verbose run shows:

	[jolsa@krava perf]$ sudo ./perf test -vv 'PMU event map aliases'
	 10: PMU events                                                      :
	 10.2: PMU event map aliases                                         :
	--- start ---
	test child forked, pid 272763
	Using CPUID GenuineIntel-6-8C-1
	intel_pt default config: tsc,mtc,mtc_period=3,psb_period=3,pt,branch
	could not find test events map
	testing core PMU cpu aliases: failed
	test child finished with -1
	---- end ----
	PMU events subtest 2: FAILED!
	[jolsa@krava perf]$ sudo ./perf test -vv 'PMU event table sanity'
	 10: PMU events                                                      :
	 10.1: PMU event table sanity                                        :
	--- start ---
	test child forked, pid 272771
	could not find test events map
	test child finished with -1
	---- end ----
	PMU events subtest 1: FAILED!

jirka


> 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
> 
> -- 
> 2.36.1.476.g0c4daa206d-goog
>