Re: [PATCH bpf-next v2 1/2] trace_helpers.c: Add helpers to poll multiple perf FDs for events

Daniel Borkmann [off-list ref] writes:

On 06/05/2018 12:26 AM, Jakub Kicinski wrote:

quoted

On Mon, 04 Jun 2018 18:33:56 +0200, Toke Høiland-Jørgensen wrote:

quoted

This adds two new helper functions to trace_helpers that supports polling
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 Høiland-Jørgensen <toke@toke.dk>

Did you take a look at tools/bpf/bpftool/map_perf_ring.c ?

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...