Re: [PATCH bpf-next v2 0/8] bpf: TCP RTT sock_ops bpf callback

[Lawrence Brakmo <brakmo@xxxxxx>]

On 7/2/19, 10:55 AM, "netdev-owner@xxxxxxxxxxxxxxx on behalf of Y Song" <netdev-owner@xxxxxxxxxxxxxxx on behalf of ys114321@xxxxxxxxx> wrote:

    On Tue, Jul 2, 2019 at 9:14 AM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
    >
    > Congestion control team would like to have a periodic callback to
    > track some TCP statistics. Let's add a sock_ops callback that can be
    > selectively enabled on a socket by socket basis and is executed for
    > every RTT. BPF program frequency can be further controlled by calling
    > bpf_ktime_get_ns and bailing out early.
    >
    > I run neper tcp_stream and tcp_rr tests with the sample program
    > from the last patch and didn't observe any noticeable performance
    > difference.
    >
    > v2:
    > * add a comment about second accept() in selftest (Yonghong Song)
    > * refer to tcp_bpf.readme in sample program (Yonghong Song)
    >
    > Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx>
    > Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
    > Cc: Priyaranjan Jha <priyarjha@xxxxxxxxxx>
    > Cc: Yuchung Cheng <ycheng@xxxxxxxxxx>
    > Cc: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
    > Acked-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
    > Acked-by: Yuchung Cheng <ycheng@xxxxxxxxxx>
    
    Ack for the whole series.
    Acked-by: Yonghong Song <yhs@xxxxxx>

Thanks, this is a very nice feature!
    
Ack for the whole series.
Acked-by: Lawrence Brakmo <brakmo@xxxxxx>

    >
    > Stanislav Fomichev (8):
    >   bpf: add BPF_CGROUP_SOCK_OPS callback that is executed on every RTT
    >   bpf: split shared bpf_tcp_sock and bpf_sock_ops implementation
    >   bpf: add dsack_dups/delivered{,_ce} to bpf_tcp_sock
    >   bpf: add icsk_retransmits to bpf_tcp_sock
    >   bpf/tools: sync bpf.h
    >   selftests/bpf: test BPF_SOCK_OPS_RTT_CB
    >   samples/bpf: add sample program that periodically dumps TCP stats
    >   samples/bpf: fix tcp_bpf.readme detach command
    >
    >  include/net/tcp.h                           |   8 +
    >  include/uapi/linux/bpf.h                    |  12 +-
    >  net/core/filter.c                           | 207 +++++++++++-----
    >  net/ipv4/tcp_input.c                        |   4 +
    >  samples/bpf/Makefile                        |   1 +
    >  samples/bpf/tcp_bpf.readme                  |   2 +-
    >  samples/bpf/tcp_dumpstats_kern.c            |  68 ++++++
    >  tools/include/uapi/linux/bpf.h              |  12 +-
    >  tools/testing/selftests/bpf/Makefile        |   3 +-
    >  tools/testing/selftests/bpf/progs/tcp_rtt.c |  61 +++++
    >  tools/testing/selftests/bpf/test_tcp_rtt.c  | 254 ++++++++++++++++++++
    >  11 files changed, 574 insertions(+), 58 deletions(-)
    >  create mode 100644 samples/bpf/tcp_dumpstats_kern.c
    >  create mode 100644 tools/testing/selftests/bpf/progs/tcp_rtt.c
    >  create mode 100644 tools/testing/selftests/bpf/test_tcp_rtt.c
    >
    > --
    > 2.22.0.410.gd8fdbe21b5-goog