From mboxrd@z Thu Jan  1 00:00:00 1970
From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Subject: Re: [PATCH bpf-next v2 1/2] trace_helpers.c: Add helpers to poll multiple perf FDs for events
Date: Tue, 05 Jun 2018 11:22:01 +0200
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Cc: netdev@vger.kernel.org,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
        Jakub Kicinski <kubakici@wp.pl>
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Daniel Borkmann <daniel@iogearbox.net> writes:

> On 06/05/2018 12:26 AM, Jakub Kicinski wrote:
>> On Mon, 04 Jun 2018 18:33:56 +0200, Toke H=C3=B8iland-J=C3=B8rgensen wro=
te:
>>> This adds two new helper functions to trace_helpers that supports polli=
ng
>>> multiple perf file descriptors for events. These are used to the XDP
>>> perf_event_output example, which needs to work with one perf fd per CPU.
>>>
>>> Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk>
>>=20
>> Did you take a look at tools/bpf/bpftool/map_perf_ring.c ?
>>=20
>> I think the ability to poll multiple FDs could be generally useful and
>> therefore better add it to libbpf.c than
>> tools/testing/selftests/bpf/trace_helpers.c?  I'm not 100% sure myself...
>
> I think for it to land in libbpf this code needs to be more generalized
> as it is right now and allowing for more flexibility like pinning RB
> processing threads to CPUs, poll handling, etc.

Hmm, so how about we leave it in trace_helpers.c for now? I don't
necessarily mind working on an addition to libbpf at some point, but
don't have time to do so short term...