Re: [External] : Re: RFC Re: [PATCH v2] perf jevents: Parse metrics during conversion

[John Garry]

On 15/11/2022 17:35, John Garry wrote:
> On 15/11/2022 17:26, Ian Rogers wrote:
> > On Thu, Nov 10, 2022 at 10:48 AM Arnaldo Carvalho de Melo
> > <acme@xxxxxxxxxx> wrote:
> > > Em Fri, Oct 28, 2022 at 10:57:02AM -0700, Ian Rogers escreveu:
> > > > On Wed, Oct 12, 2022 at 9:42 AM Ian Rogers <irogers@xxxxxxxxxx> wrote:
> > > > > Currently the 'MetricExpr' json value is passed from the json
> > > > > file to the pmu-events.c. This change introduces an expression
> > > > > tree that is parsed into. The parsing is done largely by using
> > > > > operator overloading and python's 'eval' function. Two advantages
> > > > > in doing this are:
> > > > >
> > > > > 1) Broken metrics fail at compile time rather than relying on
> > > > >     `perf test` to detect. `perf test` remains relevant for checking
> > > > >     event encoding and actual metric use.
> > > > >
> > > > > 2) The conversion to a string from the tree can minimize the
> > > > >     metric's string size, for example, preferring 1e6 over 1000000
> > > > >     and removing unnecessary whitespace. On x86 this reduces the
> > > > >     string size by 2,823bytes (0.06%).
> > > > >
> > > > > In future changes it would be possible to programmatically
> > > > > generate the json expressions (a single line of text and so a
> > > > > pain to write manually) for an architecture using the expression
> > > > > tree. This could avoid copy-pasting metrics for all architecture
> > > > > variants.
> > > > >
> > > > > Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> > > >
> > > > Ping, PTAL.
> > >
> > > That would be really nice if people working with JSON, metrics, could
> > > take a look at Ian's work and test it with their files, volunteers?
> >
> > Perhaps John could help?
>
> I'll have a look soon. I have to admit that I have not been tracking the 
> jevents changes as close as before.

At least I can try to test it... so we support python 3.6 and later, right?

I have 3.6 and acme perf/core generated pmu-events.c is ok for me, but 
this patch causes an error:

  GEN     pmu-events/pmu-events.c
 PERF_VERSION = 6.1.rc3.g39b7ecfa5b4a
 GEN     perf-archive
 GEN     perf-iostat
Traceback (most recent call last):
 File "pmu-events/jevents.py", line 7, in <module>
   import metric
 File "/home/john/kernel-dev2/tools/perf/pmu-events/metric.py", line 
399, in <module>
   class MetricGroup:
 File "/home/john/kernel-dev2/tools/perf/pmu-events/metric.py", line 
408, in MetricGroup
   'MetricGroup']]):
TypeError: 'type' object is not subscriptable
make[3]: *** [pmu-events/Build:26: pmu-events/pmu-events.c] Error 1
make[2]: *** [Makefile.perf:672: pmu-events/pmu-events-in.o] Error 2
make[2]: *** Waiting for unfinished jobs....


Any idea?

Thanks,
John