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

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Date:   Wed, 22 Jun 2022 09:36:50 +0200
From:   Jiri Olsa <olsajiri@...il.com>
To:     Ian Rogers <irogers@...gle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>,
        John Garry <john.garry@...wei.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        Felix Fietkau <nbd@....name>, Qi Liu <liuqi115@...wei.com>,
        Like Xu <likexu@...cent.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org,
        Nick Forrington <nick.forrington@....com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        James Clark <james.clark@....com>,
        Andrew Kilroy <andrew.kilroy@....com>,
        "Paul A . Clarke" <pc@...ibm.com>, Will Deacon <will@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        ananth.narayan@....com, ravi.bangoria@....com,
        santosh.shukla@....com, sandipan.das@....com,
        Caleb Biggers <caleb.biggers@...el.com>,
        Perry Taylor <perry.taylor@...el.com>,
        Kshipra Bopardikar <kshipra.bopardikar@...el.com>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v6 0/4] Rewrite jevents program in python

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@...va 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@...va 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 ?

thanks,
jirka