Re: [PATCH] perf stat: fix cvs output format

[Arnaldo Carvalho de Melo <acme@redhat.com>]

Em Tue, Mar 06, 2018 at 09:00:11AM -0800, Andi Kleen escreveu:
> On Mon, Mar 05, 2018 at 10:43:53PM -0800, Cong Wang wrote:
> > From: Ilya Pronin <ipronin@twitter.com>
> > 
> > When printing stats in CSV mode, perf stat appends extra CSV
> > separators when counter is not supported:
> > 
> > <not supported>,,L1-dcache-store-misses,mesos/bd442f34-2b4a-47df-b966-9b281f9f56fc,0,100.00,,,,
> > 
> > which causes a failure of parsing fields. The numbers of separators
> 
> Causes failure in what?
> 
> > is fixed for each line, no matter supported or not supported.
> 
> I don't think they're extra fields, there are cases where they can be filled out

My understanding was that at some place there is a if/else

	if (supported counters)
		fprintf_something with N fields, all filled in
        else
		fprintf_empty_fields with != N fields

So I think this is not about using things like 'a,b,,,,,,' but about
using different number of commas (fields) for supported/unsupported
counters, no?

- Arnaldo

> for variance, metricvalue, unit. And other code in perf too uses empty
> fields when something is not available.
> 
>         - optional usec time stamp in fractions of second (with -I xxx)
>         - optional CPU, core, or socket identifier
>         - optional number of logical CPUs aggregated
>         - counter value
>         - unit of the counter value or empty
>         - event name
>         - run time of counter
>         - percentage of measurement time the counter was running
>         - optional variance if multiple values are collected with -r  
>         - optional metric value
>         - optional unit of metric
> 
> 
> -Andi