Re: [PATCH v1 02/20] perf jevents: Add idle metric for Intel models

[Andi Kleen]

> +def Idle() -> Metric:
> +  cyc = Event("msr/mperf/")
> +  tsc = Event("msr/tsc/")
> +  low = max(tsc - cyc, 0)
> +  return Metric(
> +      "idle",
> +      "Percentage of total wallclock cycles where CPUs are in low power state (C1 or deeper sleep state)",
> +      d_ratio(low, tsc), "100%")

TBH I fail to see the advantage over the JSON. That's much more verbose
and we don't expect to have really complex metrics anyways.

And then we have a gigantic patch kit for what gain?

The motivation was the lack of comments in JSON? We could just add some
to the parser (e.g. with /* */ ).  And we could allow an JSON array for the
expression to get multiple lines.


-Andi