On Wed, Dec 21, 2022 at 02:06:18PM +0200, Alvaro Karsz wrote:
> Don't send a VIRTIO_NET_CTRL_NOTF_COAL_TX_SET or
> VIRTIO_NET_CTRL_NOTF_COAL_RX_SET command if the coalescing parameters
> haven't changed.
>
> Signed-off-by: Alvaro Karsz <[email protected]>
Why do we bother? Resending needs more code and helps
reliability ...
> ---
> drivers/net/virtio_net.c | 48 ++++++++++++++++++++++------------------
> 1 file changed, 27 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7723b2a49d8..1d7118de62a 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2760,31 +2760,37 @@ static int virtnet_send_notf_coal_cmds(struct
> virtnet_info *vi,
> struct virtio_net_ctrl_coal_tx coal_tx;
> struct virtio_net_ctrl_coal_rx coal_rx;
>
> - coal_tx.tx_usecs = cpu_to_le32(ec->tx_coalesce_usecs);
> - coal_tx.tx_max_packets = cpu_to_le32(ec->tx_max_coalesced_frames);
> - sg_init_one(&sgs_tx, &coal_tx, sizeof(coal_tx));
> -
> - if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
> - VIRTIO_NET_CTRL_NOTF_COAL_TX_SET,
> - &sgs_tx))
> - return -EINVAL;
> + if (ec->tx_coalesce_usecs != vi->tx_usecs ||
> + ec->tx_max_coalesced_frames != vi->tx_max_packets) {
> + coal_tx.tx_usecs = cpu_to_le32(ec->tx_coalesce_usecs);
> + coal_tx.tx_max_packets =
> cpu_to_le32(ec->tx_max_coalesced_frames);
> + sg_init_one(&sgs_tx, &coal_tx, sizeof(coal_tx));
> +
> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
> + VIRTIO_NET_CTRL_NOTF_COAL_TX_SET,
> + &sgs_tx))
> + return -EINVAL;
>
> - /* Save parameters */
> - vi->tx_usecs = ec->tx_coalesce_usecs;
> - vi->tx_max_packets = ec->tx_max_coalesced_frames;
> + /* Save parameters */
> + vi->tx_usecs = ec->tx_coalesce_usecs;
> + vi->tx_max_packets = ec->tx_max_coalesced_frames;
> + }
>
> - coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
> - coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);
> - sg_init_one(&sgs_rx, &coal_rx, sizeof(coal_rx));
> + if (ec->rx_coalesce_usecs != vi->rx_usecs ||
> + ec->rx_max_coalesced_frames != vi->rx_max_packets) {
> + coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
> + coal_rx.rx_max_packets =
> cpu_to_le32(ec->rx_max_coalesced_frames);
> + sg_init_one(&sgs_rx, &coal_rx, sizeof(coal_rx));
>
> - if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
> - VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,
> - &sgs_rx))
> - return -EINVAL;
> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
> + VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,
> + &sgs_rx))
> + return -EINVAL;
>
> - /* Save parameters */
> - vi->rx_usecs = ec->rx_coalesce_usecs;
> - vi->rx_max_packets = ec->rx_max_coalesced_frames;
> + /* Save parameters */
> + vi->rx_usecs = ec->rx_coalesce_usecs;
> + vi->rx_max_packets = ec->rx_max_coalesced_frames;
> + }
>
> return 0;
> }
> --
> 2.32.0
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