Re: [PATCH net-next v2 2/2] virtio-net: support dim profile fine-tuning

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 27, 2024 at 05:19:06PM +0800, Heng Qi wrote:
> Virtio-net has different types of back-end device
> implementations. In order to effectively optimize
> the dim library's gains for different device
> implementations, let's use the new interface params
> to fine-tune the profile list.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
> ---
>  drivers/net/virtio_net.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 52 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index e709d44..9b6c727 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -57,6 +57,16 @@
>  
>  #define VIRTNET_DRIVER_VERSION "1.0.0"
>  
> +/* This is copied from NET_DIM_RX_EQE_PROFILES in DIM library */

So maybe move it to a header and reuse?


> +#define VIRTNET_DIM_RX_PKTS 256
> +static struct dim_cq_moder rx_eqe_conf[] = {
> +	{.usec = 1,   .pkts = VIRTNET_DIM_RX_PKTS,},
> +	{.usec = 8,   .pkts = VIRTNET_DIM_RX_PKTS,},
> +	{.usec = 64,  .pkts = VIRTNET_DIM_RX_PKTS,},
> +	{.usec = 128, .pkts = VIRTNET_DIM_RX_PKTS,},
> +	{.usec = 256, .pkts = VIRTNET_DIM_RX_PKTS,}
> +};
> +
>  static const unsigned long guest_offloads[] = {
>  	VIRTIO_NET_F_GUEST_TSO4,
>  	VIRTIO_NET_F_GUEST_TSO6,
> @@ -3584,7 +3594,10 @@ static void virtnet_rx_dim_work(struct work_struct *work)
>  		if (!rq->dim_enabled)
>  			continue;
>  
> -		update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
> +		if (dim->profile_ix >= ARRAY_SIZE(rx_eqe_conf))
> +			dim->profile_ix = ARRAY_SIZE(rx_eqe_conf) - 1;
> +
> +		update_moder = rx_eqe_conf[dim->profile_ix];
>  		if (update_moder.usec != rq->intr_coal.max_usecs ||
>  		    update_moder.pkts != rq->intr_coal.max_packets) {
>  			err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
> @@ -3627,6 +3640,34 @@ static int virtnet_should_update_vq_weight(int dev_flags, int weight,
>  	return 0;
>  }
>  
> +static int virtnet_update_profile(struct virtnet_info *vi,
> +				  struct kernel_ethtool_coalesce *kc)
> +{
> +	int i;
> +
> +	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
> +		for (i = 0; i < NET_DIM_PARAMS_NUM_PROFILES; i++)
> +			if (kc->rx_eqe_profs[i].comps)
> +				return -EINVAL;
> +	} else {
> +		for (i = 0; i < NET_DIM_PARAMS_NUM_PROFILES; i++) {
> +			if (kc->rx_eqe_profs[i].usec != rx_eqe_conf[i].usec ||
> +			    kc->rx_eqe_profs[i].pkts != rx_eqe_conf[i].pkts ||
> +			    kc->rx_eqe_profs[i].comps)
> +				return -EINVAL;
> +		}
> +
> +		return 0;
> +	}
> +
> +	for (i = 0; i < NET_DIM_PARAMS_NUM_PROFILES; i++) {
> +		rx_eqe_conf[i].usec = kc->rx_eqe_profs[i].usec;
> +		rx_eqe_conf[i].pkts = kc->rx_eqe_profs[i].pkts;
> +	}
> +
> +	return 0;
> +}
> +
>  static int virtnet_set_coalesce(struct net_device *dev,
>  				struct ethtool_coalesce *ec,
>  				struct kernel_ethtool_coalesce *kernel_coal,
> @@ -3653,6 +3694,10 @@ static int virtnet_set_coalesce(struct net_device *dev,
>  		}
>  	}
>  
> +	ret = virtnet_update_profile(vi, kernel_coal);
> +	if (ret)
> +		return ret;
> +
>  	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL))
>  		ret = virtnet_send_notf_coal_cmds(vi, ec);
>  	else
> @@ -3689,6 +3734,10 @@ static int virtnet_get_coalesce(struct net_device *dev,
>  			ec->tx_max_coalesced_frames = 1;
>  	}
>  
> +	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
> +		memcpy(kernel_coal->rx_eqe_profs, rx_eqe_conf,
> +		       sizeof(rx_eqe_conf));
> +
>  	return 0;
>  }
>  
> @@ -3868,7 +3917,8 @@ static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info)
>  
>  static const struct ethtool_ops virtnet_ethtool_ops = {
>  	.supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |
> -		ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
> +		ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX |
> +		ETHTOOL_COALESCE_RX_EQE_PROFILE,
>  	.get_drvinfo = virtnet_get_drvinfo,
>  	.get_link = ethtool_op_get_link,
>  	.get_ringparam = virtnet_get_ringparam,
> -- 
> 1.8.3.1