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Date:   Mon, 29 Jun 2020 14:02:04 +0200 (CEST)
From:   Michael Petlan <mpetlan@redhat.com>
To:     Andi Kleen <ak@linux.intel.com>
cc:     Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Kajol Jain <kjain@linux.ibm.com>,
        John Garry <john.garry@huawei.com>,
        "Paul A. Clarke" <pc@us.ibm.com>,
        Stephane Eranian <eranian@google.com>
Subject: Re: [RFC 00/10] perf tools: Add support to reuse metric
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On Fri, 26 Jun 2020, Andi Kleen wrote:
> > The name could be a metric or an event, the logic for each is quite
> 
> I would say collisions are unlikely. Event names follow quite structured
> patterns.

But across various architectures? I guess event names can be arbitrary.
In perftool-testsuite, I use the following regexp to match event names:
[\w\-\:\/_=,]+

> 
> > different. You could look up an event and when it fails assume it was
> > a metric, but I like the simplicity of this approach.
> 
> I don't think it's simpler for the user.
>
I think it should be clear at the user level whether they're using an event
or a metric (basically a couple of events together). I don't hiding too
much of details from users is any good.

> > Maybe this
> > change could be adopted more widely with something like "perf stat -e
> > metric:IPC -a -I 1000" rather than the current "perf stat -M IPC -a -I
> > 1000".
> 
> I thought about just adding metrics to -e, without metric: of course.
> 
> -Andi
> 
>