[v3,6/7] net/null: replace rte atomics with GCC builtin atomics

  Replace the use of rte_atomic.h types and functions, instead use GCC
supplied C++11 memory model builtins.

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---
 drivers/net/null/rte_eth_null.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)
  

Hello Tetsuya,

Review please.


On Thu, Mar 23, 2023 at 11:54 PM Tyler Retzlaff
<roretzla@linux.microsoft.com> wrote:
>
> Replace the use of rte_atomic.h types and functions, instead use GCC
> supplied C++11 memory model builtins.
>
> Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> ---
>  drivers/net/null/rte_eth_null.c | 28 ++++++++++++++++++----------
>  1 file changed, 18 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/null/rte_eth_null.c b/drivers/net/null/rte_eth_null.c
> index 47d9554..31081af 100644
> --- a/drivers/net/null/rte_eth_null.c
> +++ b/drivers/net/null/rte_eth_null.c
> @@ -37,8 +37,8 @@ struct null_queue {
>         struct rte_mempool *mb_pool;
>         struct rte_mbuf *dummy_packet;
>
> -       rte_atomic64_t rx_pkts;
> -       rte_atomic64_t tx_pkts;
> +       uint64_t rx_pkts;
> +       uint64_t tx_pkts;
>  };
>
>  struct pmd_options {
> @@ -101,7 +101,8 @@ struct pmd_internals {
>                 bufs[i]->port = h->internals->port_id;
>         }
>
> -       rte_atomic64_add(&(h->rx_pkts), i);
> +       /* NOTE: review for potential ordering optimization */
> +       __atomic_fetch_add(&h->rx_pkts, i, __ATOMIC_SEQ_CST);
>
>         return i;
>  }
> @@ -128,7 +129,8 @@ struct pmd_internals {
>                 bufs[i]->port = h->internals->port_id;
>         }
>
> -       rte_atomic64_add(&(h->rx_pkts), i);
> +       /* NOTE: review for potential ordering optimization */
> +       __atomic_fetch_add(&h->rx_pkts, i, __ATOMIC_SEQ_CST);
>
>         return i;
>  }
> @@ -152,7 +154,8 @@ struct pmd_internals {
>         for (i = 0; i < nb_bufs; i++)
>                 rte_pktmbuf_free(bufs[i]);
>
> -       rte_atomic64_add(&(h->tx_pkts), i);
> +       /* NOTE: review for potential ordering optimization */
> +       __atomic_fetch_add(&h->tx_pkts, i, __ATOMIC_SEQ_CST);
>
>         return i;
>  }
> @@ -174,7 +177,8 @@ struct pmd_internals {
>                 rte_pktmbuf_free(bufs[i]);
>         }
>
> -       rte_atomic64_add(&(h->tx_pkts), i);
> +       /* NOTE: review for potential ordering optimization */
> +       __atomic_fetch_add(&h->tx_pkts, i, __ATOMIC_SEQ_CST);
>
>         return i;
>  }
> @@ -316,8 +320,9 @@ struct pmd_internals {
>                         RTE_MIN(dev->data->nb_rx_queues,
>                                 RTE_DIM(internal->rx_null_queues)));
>         for (i = 0; i < num_stats; i++) {
> +               /* NOTE: review for atomic access */
>                 igb_stats->q_ipackets[i] =
> -                       internal->rx_null_queues[i].rx_pkts.cnt;
> +                       internal->rx_null_queues[i].rx_pkts;
>                 rx_total += igb_stats->q_ipackets[i];
>         }
>
> @@ -325,8 +330,9 @@ struct pmd_internals {
>                         RTE_MIN(dev->data->nb_tx_queues,
>                                 RTE_DIM(internal->tx_null_queues)));
>         for (i = 0; i < num_stats; i++) {
> +               /* NOTE: review for atomic access */
>                 igb_stats->q_opackets[i] =
> -                       internal->tx_null_queues[i].tx_pkts.cnt;
> +                       internal->tx_null_queues[i].tx_pkts;
>                 tx_total += igb_stats->q_opackets[i];
>         }
>
> @@ -347,9 +353,11 @@ struct pmd_internals {
>
>         internal = dev->data->dev_private;
>         for (i = 0; i < RTE_DIM(internal->rx_null_queues); i++)
> -               internal->rx_null_queues[i].rx_pkts.cnt = 0;
> +               /* NOTE: review for atomic access */
> +               internal->rx_null_queues[i].rx_pkts = 0;
>         for (i = 0; i < RTE_DIM(internal->tx_null_queues); i++)
> -               internal->tx_null_queues[i].tx_pkts.cnt = 0;
> +               /* NOTE: review for atomic access */
> +               internal->tx_null_queues[i].tx_pkts = 0;
>
>         return 0;
>  }
> --
> 1.8.3.1
>