| Message ID | 50A3975B.7020608@myri.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, 2012-11-14 at 08:06 -0500, Andrew Gallatin wrote: > > Unlike LRO, GRO requires that vlan tags be removed before > aggregation can occur. Since the myri10ge NIC does not support > hardware vlan tag offload, we must remove the tag in the driver > to achieve performance comparable to LRO for vlan tagged frames. > > Signed-off-by: Andrew Gallatin <gallatin@myri.com> > --- > drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 47 > ++++++++++++++++++++++ > 1 file changed, 47 insertions(+) > > diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c > b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c > index a5ab2f2..b9b6dfd 100644 > --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c > +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c > @@ -1264,6 +1264,48 @@ myri10ge_unmap_rx_page(struct pci_dev *pdev, > } > } > > +/* > + * GRO does not support acceleration of tagged vlan frames, and > + * this NIC does not support vlan tag offload, so we must pop > + * the tag ourselves to be able to achieve GRO performance that > + * is comparable to LRO. > + */ > + > +static inline void > +myri10ge_vlan_rx(struct net_device *dev, void *addr, struct sk_buff *skb) > +{ > + u8 *va; > + struct vlan_ethhdr *veh; > + struct ethhdr *eh; > + struct skb_frag_struct *frag; > + u16 proto; > + > + va = addr; > + va += MXGEFW_PAD; > + veh = (struct vlan_ethhdr *) va; > + if ((dev->features & (NETIF_F_HW_VLAN_RX | NETIF_F_GRO)) == > + (NETIF_F_HW_VLAN_RX | NETIF_F_GRO) && > + (veh->h_vlan_proto == ntohs(ETH_P_8021Q))) { > + /* fixup csum if needed */ > + if (skb->ip_summed == CHECKSUM_COMPLETE) > + skb->csum = csum_sub(skb->csum, > + csum_partial(va + ETH_HLEN, > + VLAN_HLEN, 0)); > + /* pop tag */ > + __vlan_hwaccel_put_tag(skb, ntohs(veh->h_vlan_TCI)); > + proto = veh->h_vlan_encapsulated_proto; I am not sure you need this @proto ? > + memmove(va + VLAN_HLEN, va, ETH_HLEN); You could only memmove the mac addresses (2 * ETH_ALEN) To not touch the proto (and avoid possible aliasing problems) > + va += VLAN_HLEN; > + eh = (struct ethhdr *)va; > + eh->h_proto = proto; and this should not be needed ? > + skb->len -= VLAN_HLEN; > + skb->data_len -= VLAN_HLEN; > + frag = skb_shinfo(skb)->frags; > + frag->page_offset += VLAN_HLEN; > + skb_frag_size_set(frag, skb_frag_size(frag) - VLAN_HLEN); > + } > +} > + -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/14/12 09:46, Eric Dumazet wrote: > On Wed, 2012-11-14 at 08:06 -0500, Andrew Gallatin wrote: >> >> Unlike LRO, GRO requires that vlan tags be removed before >> aggregation can occur. Since the myri10ge NIC does not support >> hardware vlan tag offload, we must remove the tag in the driver >> to achieve performance comparable to LRO for vlan tagged frames. >> >> Signed-off-by: Andrew Gallatin <gallatin@myri.com> >> --- >> drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 47 >> ++++++++++++++++++++++ >> 1 file changed, 47 insertions(+) >> >> diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c >> b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c >> index a5ab2f2..b9b6dfd 100644 >> --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c >> +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c >> @@ -1264,6 +1264,48 @@ myri10ge_unmap_rx_page(struct pci_dev *pdev, >> } >> } >> >> +/* >> + * GRO does not support acceleration of tagged vlan frames, and >> + * this NIC does not support vlan tag offload, so we must pop >> + * the tag ourselves to be able to achieve GRO performance that >> + * is comparable to LRO. >> + */ >> + >> +static inline void >> +myri10ge_vlan_rx(struct net_device *dev, void *addr, struct sk_buff *skb) >> +{ >> + u8 *va; >> + struct vlan_ethhdr *veh; >> + struct ethhdr *eh; >> + struct skb_frag_struct *frag; >> + u16 proto; >> + >> + va = addr; >> + va += MXGEFW_PAD; >> + veh = (struct vlan_ethhdr *) va; >> + if ((dev->features & (NETIF_F_HW_VLAN_RX | NETIF_F_GRO)) == >> + (NETIF_F_HW_VLAN_RX | NETIF_F_GRO) && >> + (veh->h_vlan_proto == ntohs(ETH_P_8021Q))) { >> + /* fixup csum if needed */ >> + if (skb->ip_summed == CHECKSUM_COMPLETE) >> + skb->csum = csum_sub(skb->csum, >> + csum_partial(va + ETH_HLEN, >> + VLAN_HLEN, 0)); >> + /* pop tag */ >> + __vlan_hwaccel_put_tag(skb, ntohs(veh->h_vlan_TCI)); >> + proto = veh->h_vlan_encapsulated_proto; > I am not sure you need this @proto ? > >> + memmove(va + VLAN_HLEN, va, ETH_HLEN); > > You could only memmove the mac addresses (2 * ETH_ALEN) > To not touch the proto (and avoid possible aliasing problems) > >> + va += VLAN_HLEN; >> + eh = (struct ethhdr *)va; >> + eh->h_proto = proto; > > and this should not be needed ? Indeed, your suggestion works and is simpler and less risky. Thank you for your help. I also think that I am making a mistake by only popping the tag when GRO is enabled. My fear is that something will become confused when skb->dev->features contains NETIF_F_HW_VLAN_RX, but the tag is not decap'ed. So I will remove the check for NETIF_F_GRO when popping the vlan tag. Thanks, Drew -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c index a5ab2f2..b9b6dfd 100644 --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c @@ -1264,6 +1264,48 @@ myri10ge_unmap_rx_page(struct pci_dev *pdev, } } +/* + * GRO does not support acceleration of tagged vlan frames, and + * this NIC does not support vlan tag offload, so we must pop + * the tag ourselves to be able to achieve GRO performance that + * is comparable to LRO. + */ + +static inline void +myri10ge_vlan_rx(struct net_device *dev, void *addr, struct sk_buff *skb) +{ + u8 *va; + struct vlan_ethhdr *veh; + struct ethhdr *eh; + struct skb_frag_struct *frag; + u16 proto; + + va = addr; + va += MXGEFW_PAD; + veh = (struct vlan_ethhdr *) va; + if ((dev->features & (NETIF_F_HW_VLAN_RX | NETIF_F_GRO)) == + (NETIF_F_HW_VLAN_RX | NETIF_F_GRO) && + (veh->h_vlan_proto == ntohs(ETH_P_8021Q))) { + /* fixup csum if needed */ + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->csum = csum_sub(skb->csum, + csum_partial(va + ETH_HLEN, + VLAN_HLEN, 0)); + /* pop tag */ + __vlan_hwaccel_put_tag(skb, ntohs(veh->h_vlan_TCI)); + proto = veh->h_vlan_encapsulated_proto; + memmove(va + VLAN_HLEN, va, ETH_HLEN); + va += VLAN_HLEN; + eh = (struct ethhdr *)va; + eh->h_proto = proto; + skb->len -= VLAN_HLEN; + skb->data_len -= VLAN_HLEN; + frag = skb_shinfo(skb)->frags; + frag->page_offset += VLAN_HLEN; + skb_frag_size_set(frag, skb_frag_size(frag) - VLAN_HLEN); + } +} + static inline int myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum) { @@ -1329,6 +1371,7 @@ myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum) skb->ip_summed = CHECKSUM_COMPLETE; skb->csum = csum; } + myri10ge_vlan_rx(mgp->dev, va, skb); skb_record_rx_queue(skb, ss - &mgp->ss[0]);
Unlike LRO, GRO requires that vlan tags be removed before aggregation can occur. Since the myri10ge NIC does not support hardware vlan tag offload, we must remove the tag in the driver to achieve performance comparable to LRO for vlan tagged frames. Signed-off-by: Andrew Gallatin <gallatin@myri.com> --- drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 47 ++++++++++++++++++++++ 1 file changed, 47 insertions(+) napi_gro_frags(&ss->napi); @@ -3854,6 +3897,10 @@ static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent) netdev->netdev_ops = &myri10ge_netdev_ops; netdev->mtu = myri10ge_initial_mtu; netdev->hw_features = mgp->features | NETIF_F_RXCSUM; + + /* fake NETIF_F_HW_VLAN_RX for good GRO performance */ + netdev->hw_features |= NETIF_F_HW_VLAN_RX; + netdev->features = netdev->hw_features; if (dac_enabled)