Re: [PATCH net-next v3 4/4] selftests: net: udpgso_bench_tx: Cater for pending datagrams zerocopy benchmarking

[Willem de Bruijn]

On Tue, Jan 31, 2023 at 4:01 PM Andrei Gherzan
<andrei.gherzan@xxxxxxxxxxxxx> wrote:
>
> The test tool can check that the zerocopy number of completions value is
> valid taking into consideration the number of datagram send calls. This can
> catch the system into a state where the datagrams are still in the system
> (for example in a qdisk, waiting for the network interface to return a
> completion notification, etc).
>
> This change adds a retry logic of computing the number of completions up to
> a configurable (via CLI) timeout (default: 2 seconds).
>
> Fixes: 79ebc3c26010 ("net/udpgso_bench_tx: options to exercise TX CMSG")
> Signed-off-by: Andrei Gherzan <andrei.gherzan@xxxxxxxxxxxxx>
> Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> ---
>  tools/testing/selftests/net/udpgso_bench_tx.c | 34 +++++++++++++++----
>  1 file changed, 27 insertions(+), 7 deletions(-)
>
> diff --git a/tools/testing/selftests/net/udpgso_bench_tx.c b/tools/testing/selftests/net/udpgso_bench_tx.c
> index b47b5c32039f..ef887842522a 100644
> --- a/tools/testing/selftests/net/udpgso_bench_tx.c
> +++ b/tools/testing/selftests/net/udpgso_bench_tx.c
> @@ -62,6 +62,7 @@ static int    cfg_payload_len = (1472 * 42);
>  static int     cfg_port        = 8000;
>  static int     cfg_runtime_ms  = -1;
>  static bool    cfg_poll;
> +static int     cfg_poll_loop_timeout_ms = 2000;
>  static bool    cfg_segment;
>  static bool    cfg_sendmmsg;
>  static bool    cfg_tcp;
> @@ -235,16 +236,17 @@ static void flush_errqueue_recv(int fd)
>         }
>  }
>
> -static void flush_errqueue(int fd, const bool do_poll)
> +static void flush_errqueue(int fd, const bool do_poll,
> +               unsigned long poll_timeout, const bool poll_err)

nit: his indentation looks off though

>  {
>         if (do_poll) {
>                 struct pollfd fds = {0};
>                 int ret;
>
>                 fds.fd = fd;
> -               ret = poll(&fds, 1, 500);
> +               ret = poll(&fds, 1, poll_timeout);
>                 if (ret == 0) {
> -                       if (cfg_verbose)
> +                       if ((cfg_verbose) && (poll_err))
>                                 fprintf(stderr, "poll timeout\n");
>                 } else if (ret < 0) {
>                         error(1, errno, "poll");
> @@ -254,6 +256,20 @@ static void flush_errqueue(int fd, const bool do_poll)
>         flush_errqueue_recv(fd);
>  }