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

[Ian Rogers]

On Wed, Jun 22, 2022 at 12:36 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote:
>
> On Wed, Jun 22, 2022 at 09:12:40AM +0200, Jiri Olsa wrote:
> > 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!
>
> ah, ok I did not notice:
>
> Makefile.config:909: Python interpreter too old (older than 3.6) disabling jevent generation
>
> I installed python3-devel and it's ok
>
> should we make above tests SKIP in case there's empty pmu-events.c ?

Hmm.. I didn't know the empty case was failing, that seems
sub-optimal. It'd also be nice to report here a skip for not being
compiled in rather than a pass. Let me take a look later.

Thanks,
Ian

> thanks,
> jirka