Re: [PATCH net-next 3/5] netdev_features: convert NETIF_F_LLTX to dev->lltx

Eric Dumazet
2024-06-25T14:01:07Z

On Tue, Jun 25, 2024 at 1:50 PM Alexander Lobakin
<aleksander.lobakin@intel.com> wrote:
>
> NETIF_F_LLTX can't be changed via Ethtool and is not a feature,
> rather an attribute, very similar to IFF_NO_QUEUE (and hot).
> Free one netdev_features_t bit and make it a private flag.

> Now the LLTX bit sits in the first ("Tx read-mostly") cacheline
> next to netdev_ops, so that the start_xmit locking code will
> potentially read 1 cacheline less, nice.

Are you sure ?

I certainly appreciate the data locality effort but
dev->features is read anyway in TX fast path from netif_skb_features()

Thanks.