From: Tom Herbert <tom@herbertland.com>
To: "Rustad, Mark D" <mark.d.rustad@intel.com>
Cc: "Kirsher, Jeffrey T" <jeffrey.t.kirsher@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
"nhorman@redhat.com" <nhorman@redhat.com>,
"sassmann@redhat.com" <sassmann@redhat.com>,
"jogreene@redhat.com" <jogreene@redhat.com>
Subject: Re: [net-next 05/19] ixgbe: Add support for UDP-encapsulated tx checksum offload
Date: Wed, 2 Sep 2015 16:21:16 -0700 [thread overview]
Message-ID: <CALx6S36-CAWVme16XOT6Gj5HnkFCbkQgsSBPVjXbzWbRLnqYuw@mail.gmail.com> (raw)
In-Reply-To: <F63CFE64-29E1-484B-B19B-269FAAA9C54B@intel.com>
On Wed, Sep 2, 2015 at 9:46 AM, Rustad, Mark D <mark.d.rustad@intel.com> wrote:
>> On Sep 1, 2015, at 8:17 PM, Tom Herbert <tom@herbertland.com> wrote:
>>
>> I suspect this is not UDP-encapsulation specific, will it work with
>> TCP/IP/IP, TCP/IP/GRE etc.?
>
Mark, another question in this area of code. Looking at ixgbe_tx_csum,
I'm wondering what happens with those default cases for the switch
statements. If those are hit for whatever reason does that mean the
checksum is never resolved? It seems like if the device couldn't
handle these cases then skb_checksum_help should be called to set the
checksum. In particular I am wondering what happens in the case that a
TCP or UDP packet is sent in IPv6 with an extension header present (so
default is taken in switch (l4_hdr)). Would the checksum be properly
set in this case?
Thanks,
Tom
> It could do more, but this is what has been tested up to this point.
>
>> Isn't there anyway the ixgbe could just be made to NETIF_HW_CSUM? That
>> would be so much more straightforward and support nearly all use cases
>> without needing to jump through all these hoops.
>
> Well, the description says:
>
> ---
> Note: NETIF_F_HW_CSUM is a superset of NETIF_F_IP_CSUM + NETIF_F_IPV6_CSUM.
> It means that device can fill TCP/UDP-like checksum anywhere in the packets
> whatever headers there might be.
> ---
>
> The device can't do whatever, wherever. There is always a limit to the offset to the inner headers that can be handled, for instance.
>
> --
> Mark Rustad, Networking Division, Intel Corporation
>
next prev parent reply other threads:[~2015-09-02 23:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-02 1:13 [net-next 00/19][pull request] Intel Wired LAN Driver Updates 2015-09-01 Jeff Kirsher
2015-09-02 1:13 ` [net-next 01/19] i40e: Set defport behavior for the Main VSI when in promiscuous mode Jeff Kirsher
2015-09-02 1:13 ` [net-next 02/19] ixgbe: add new function to check for management presence Jeff Kirsher
2015-09-02 1:13 ` [net-next 03/19] ixgbe: Assign set_phy_power dynamically where needed Jeff Kirsher
2015-09-02 1:13 ` [net-next 04/19] ixgbe: Check whether FDIRCMD writes actually complete Jeff Kirsher
2015-09-02 1:13 ` [net-next 05/19] ixgbe: Add support for UDP-encapsulated tx checksum offload Jeff Kirsher
2015-09-02 3:17 ` Tom Herbert
2015-09-02 16:46 ` Rustad, Mark D
2015-09-02 17:38 ` Tom Herbert
2015-09-02 20:56 ` Or Gerlitz
2015-09-02 21:07 ` Or Gerlitz
2015-09-02 22:34 ` Tom Herbert
2015-09-02 23:21 ` Tom Herbert [this message]
2015-09-03 0:21 ` Rustad, Mark D
2015-09-02 1:13 ` [net-next 06/19] ixgbe: Add support for VXLAN RX offloads Jeff Kirsher
2015-09-02 3:31 ` Tom Herbert
2015-09-02 16:53 ` Rustad, Mark D
2015-09-02 1:13 ` [net-next 07/19] ixgbe: Add support for entering low power link up state Jeff Kirsher
2015-09-02 1:13 ` [net-next 08/19] ixgbe: add get_bus_info method for X550 Jeff Kirsher
2015-09-02 1:13 ` [net-next 09/19] ixgbe: add new bus type for intergrated I/O interface (IOSF) Jeff Kirsher
2015-09-02 1:13 ` [net-next 10/19] ixgbe: Remove unused PCI bus types Jeff Kirsher
2015-09-02 1:13 ` [net-next 11/19] ixgbe: use kzalloc for allocating one thing Jeff Kirsher
2015-09-02 1:13 ` [net-next 12/19] ixgbe: Remove second instance of lan_id variable Jeff Kirsher
2015-09-02 1:13 ` [net-next 13/19] ixgbe: cleanup to use cached mask value Jeff Kirsher
2015-09-02 1:13 ` [net-next 14/19] ixgbe: Avoid needless PHY access on copper phys Jeff Kirsher
2015-09-02 1:13 ` [net-next 15/19] ixgbe: support for ethtool set_rxfh Jeff Kirsher
2015-09-02 1:14 ` [net-next 16/19] ixgbe: fix bounds checking in ixgbe_setup_tc for 82598 Jeff Kirsher
2015-09-02 1:14 ` [net-next 17/19] ixgbe: Add support for reporting 2.5G link speed Jeff Kirsher
2015-09-02 1:14 ` [net-next 18/19] ixgbe: Remove bimodal SR-IOV disabling Jeff Kirsher
2015-09-02 1:14 ` [net-next 19/19] ixgbe: Resolve "initialized field overwritten" warnings Jeff Kirsher
2015-09-02 3:19 ` [net-next 00/19][pull request] Intel Wired LAN Driver Updates 2015-09-01 David Miller
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