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Date:   Thu, 7 Jan 2021 11:23:44 +0000
From:   Qais Yousef <qais.yousef@arm.com>
To:     Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc:     Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        bpf <bpf@vger.kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Phil Auld <pauld@redhat.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        vincent.donnefort@arm.com, Ingo Molnar <mingo@redhat.com>,
        vincent.guittot@linaro.org, LKML <linux-kernel@vger.kernel.org>,
        Valentin Schneider <valentin.schneider@arm.com>
Subject: Re: [PATCH v2] sched/debug: Add new tracepoint to track cpu_capacity
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On 01/06/21 15:42, Andrii Nakryiko wrote:
> On Wed, Jan 6, 2021 at 3:27 AM Qais Yousef <qais.yousef@arm.com> wrote:
> >
> > On 01/05/21 08:44, Alexei Starovoitov wrote:
> > > > Any pointer to an example test I could base this on?
> > >
> > > selftests/bpf/
> >
> > I was hoping for something more elaborate. I thought there's something already
> > there that do some verification for raw tracepoint that I could either extend
> > or replicate. Otherwise this could end up being a time sink for me and I'm not
> > keen on jumping down this rabbit hole.
> 
> One way would be to add either another custom tracepoint definition to
> a test module or modify the existing one to be a bare tracepoint. See
> links below.
> 
> If it's easy to trigger those tracepoints from user-space on demand,
> writing a similar (to module_attach) selftest for in-kernel tracepoint
> is trivial.
> 
>   [0] https://github.com/torvalds/linux/blob/master/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
>   [1] https://github.com/torvalds/linux/blob/master/tools/testing/selftests/bpf/progs/test_module_attach.c#L12-L18
>   [2] https://github.com/torvalds/linux/blob/master/tools/testing/selftests/bpf/prog_tests/module_attach.c

Thanks a lot Andrii. That will make it much easier to figure out something.

Cheers

--
Qais Yousef