Re: [PATCH net-next v4 2/2] selftests: virtio_net: add buffer circulation test

[Jason Wang]

On Thu, Feb 5, 2026 at 3:36 AM Vishwanath Seshagiri <vishs@xxxxxxxx> wrote:
>
> Add iperf3-based test to verify RX buffer handling under load.
> Optionally logs page_pool tracepoints when available.
>
> Signed-off-by: Vishwanath Seshagiri <vishs@xxxxxxxx>
> ---
>  .../drivers/net/virtio_net/basic_features.sh  | 86 +++++++++++++++++++
>  1 file changed, 86 insertions(+)
>
> diff --git a/tools/testing/selftests/drivers/net/virtio_net/basic_features.sh b/tools/testing/selftests/drivers/net/virtio_net/basic_features.sh
> index cf8cf816ed48..fa98505c4674 100755
> --- a/tools/testing/selftests/drivers/net/virtio_net/basic_features.sh
> +++ b/tools/testing/selftests/drivers/net/virtio_net/basic_features.sh
> @@ -6,6 +6,7 @@
>  ALL_TESTS="
>         initial_ping_test
>         f_mac_test
> +       buffer_circulation_test
>  "
>
>  source virtio_net_common.sh
> @@ -16,6 +17,8 @@ source "$lib_dir"/../../../net/forwarding/lib.sh
>  h1=${NETIFS[p1]}
>  h2=${NETIFS[p2]}
>
> +IPERF_SERVER_PID=""
> +
>  h1_create()
>  {
>         simple_if_init $h1 $H1_IPV4/24 $H1_IPV6/64
> @@ -83,6 +86,84 @@ f_mac_test()
>         log_test "$test_name"
>  }
>
> +buffer_circulation_test()
> +{
> +       RET=0
> +       local test_name="buffer circulation"
> +       local tracefs="/sys/kernel/tracing"
> +
> +       if ! check_command iperf3; then
> +               log_test_skip "$test_name" "iperf3 not installed"
> +               return 0
> +       fi
> +
> +       setup_cleanup
> +       setup_prepare
> +
> +       ping -c 1 -I "$h1" "$H2_IPV4" >/dev/null
> +       if [ $? -ne 0 ]; then
> +               check_err 1 "Ping failed"
> +               log_test "$test_name"
> +               return
> +       fi
> +
> +       local rx_start=$(cat /sys/class/net/"$h2"/statistics/rx_packets)
> +       local tx_start=$(cat /sys/class/net/"$h1"/statistics/tx_packets)
> +
> +       if [ -d "$tracefs/events/page_pool" ]; then
> +               echo > "$tracefs/trace"
> +               echo 1 > "$tracefs/events/page_pool/enable"
> +       fi
> +
> +       local port=$(shuf -i 49152-65535 -n 1)
> +
> +       iperf3 -s -1 --bind-dev "$h2" -p "$port" &>/dev/null &
> +       IPERF_SERVER_PID=$!
> +       sleep 1

Nit:

It's better to use a more robust detecting instead of a sleep 1.

Thanks