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Date:   Wed, 1 Sep 2021 10:36:40 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Nakamura Shun <nakamura.shun@fujitsu.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Rob Herring <robh@kernel.org>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Subject: Re: libperf: lack of interface
Message-ID: <YS+B6PVHtiTmqZS+@kernel.org>
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Em Wed, Sep 01, 2021 at 09:45:10AM +0000, nakamura.shun@fujitsu.com escreveu:
> Hello.
> 
> I'm trying to change rdpmc test in perf_event_tests[1] to use libperf, but libperf doesn't have enough interfaces.
> Does anyone plan to implement any of these libperf features?
> 
> - Interfaces that can run ioctl (PERF_EVENT_IOC_RESET) from userland
> - Interfaces that can run fcntl (SIGIO) from userland
> 
> [1] https://github.com/deater/perf_event_tests/tree/master/tests/rdpmc

So, while in this specific case you should probably follow PeterZ's
advice, feel free to submit patches moving stuff that is in
tools/perf/util/ to tools/lib/perf/ (libperf) when you have a reasonable
use case, such as Vince's test suite.

We can then discuss if any adjustment is needed, but doing it this
piecemeal way, with justification, should be a good way to enrich
libperf with things that are in quiescent state in tools/perf/util/ and
that have external users.

Thanks,

- Arnaldo