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mlxsw: Enable Tx checksum offload

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The device is able to checksum plain TCP / UDP packets over IPv4 / IPv6
when the 'ipcs' bit in the send descriptor is set. Advertise support for
the 'NETIF_F_IP{,6}_CSUM' features in net devices registered by the
driver and VLAN uppers and set the 'ipcs' bit when the stack requests Tx
checksum offload.

Note that the device also calculates the IPv4 checksum, but it first
zeroes the current checksum so there should not be any difference
compared to the checksum calculated by the kernel.

On SN5600 (Spectrum-4) there is about 10% improvement in Tx packet rate
with 1400 byte packets when using pktgen.

Tested on Spectrum-{1,2,3,4} with all the combinations of IPv4 / IPv6,
TCP / UDP, with and without VLAN.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/8dc86c95474ce10572a0fa83b8adb0259558e982.1738950446.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Ido Schimmel
2025-02-07 19:00:44 +01:00
committed by Jakub Kicinski
parent 3337064f42
commit 907dd32b4a
3 changed files with 11 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/net/ethernet/mellanox/mlxsw/pci.c
+2
View File
@@ -2214,6 +2214,8 @@ static int mlxsw_pci_skb_transmit(void *bus_priv, struct sk_buff *skb,
for (i++; i < MLXSW_PCI_WQE_SG_ENTRIES; i++)
mlxsw_pci_wqe_byte_count_set(wqe, i, 0);
mlxsw_pci_wqe_ipcs_set(wqe, skb->ip_summed == CHECKSUM_PARTIAL);
/* Everything is set up, ring producer doorbell to get HW going */
q->producer_counter++;
mlxsw_pci_queue_doorbell_producer_ring(mlxsw_pci, q);
drivers/net/ethernet/mellanox/mlxsw/pci_hw.h
+5
View File
@@ -90,6 +90,11 @@ MLXSW_ITEM32(pci, wqe, lp, 0x00, 30, 1);
*/
MLXSW_ITEM32(pci, wqe, type, 0x00, 23, 4);
/* pci_wqe_ipcs
* Calculate IPv4 and TCP / UDP checksums.
*/
MLXSW_ITEM32(pci, wqe, ipcs, 0x00, 14, 1);
/* pci_wqe_byte_count
* Size of i-th scatter/gather entry, 0 if entry is unused.
*/
drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+4 -2
View File
@@ -1574,8 +1574,10 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u16 local_port,
netif_carrier_off(dev);
dev->features |= NETIF_F_SG | NETIF_F_HW_VLAN_CTAG_FILTER |
NETIF_F_HW_TC;
dev->hw_features |= NETIF_F_HW_TC | NETIF_F_LOOPBACK;
NETIF_F_HW_TC | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
dev->hw_features |= NETIF_F_HW_TC | NETIF_F_LOOPBACK |
NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
dev->vlan_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
dev->lltx = true;
dev->netns_local = true;