On Wed, Oct 29, 2025 at 4:20 PM Paolo Abeni <[email protected]> wrote: > > On 10/29/25 2:24 AM, Jason Wang wrote: > > From: "Michael S. Tsirkin" <[email protected]> > > > > Changing alignment of header would mean it's no longer safe to cast a > > 2 byte aligned pointer between formats. Use two 16 bit fields to make > > it 2 byte aligned as previously. > > > > This fixes the performance regression since > > commit ("virtio_net: enable gso over UDP tunnel support.") as it uses > > virtio_net_hdr_v1_hash_tunnel which embeds > > virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net > > shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps. > > > > Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.") > > Cc: [email protected] > > Signed-off-by: Michael S. Tsirkin <[email protected]> > > Signed-off-by: Jason Wang <[email protected]> > > Whoops, I replied to the older thread before reading this one. > > Acked-by: Paolo Abeni <[email protected]>
I apologize, build will be broken since commit b2284768c6b32aa224ca7d0ef0741beb434f03aa Author: Jason Wang <[email protected]> Date: Wed Oct 22 11:44:21 2025 +0800 virtio-net: zero unused hash fields I will prepare a new version. Btw, it looks like there's an uAPI change that may break builds of the userspace: diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h index 8bf27ab8bcb4..1db45b01532b 100644 --- a/include/uapi/linux/virtio_net.h +++ b/include/uapi/linux/virtio_net.h @@ -193,7 +193,8 @@ struct virtio_net_hdr_v1 { struct virtio_net_hdr_v1_hash { struct virtio_net_hdr_v1 hdr; - __le32 hash_value; + __le16 hash_value_lo; + __le16 hash_value_hi; We can have a kernel only version for this but it probably means we need a kernel only version for all the future extension of vnet header? Thanks >
