Re: [dpdk-dev] ixgbe tcp cksum offload

["Tim Deng" <dpdkdev@126.com>]

Thanks Bruce so much! That perfectly solves my problem.
Tim


At 2015-05-25 18:28:48, "Bruce Richardson" <bruce.richardson@intel.com> wrote:
>On Mon, May 25, 2015 at 06:15:23PM +0800, Tim Deng wrote:
>> Hi,
>> 
>> 
>> I am trying to use ixgbe tcp cksum h/w offload by following steps:
>> - populate pseudo cksum
>> - set l2_len, l3_len, l4_len
>> - set ol_flags
>> 
>> 
>> But I found the pkt doesn't get right h/w checksum by sniffing on recv side, and TCP cksum still leave with the original pseudo cksum. 
>> And I verified those meta are correctly set, e.g. a TCP syn pkt:
>> l2_len = 14, l3_len = 20, l4_len = 40 (with some tcp options),
>> and ol_flags = 0x90000000000000 which means PKT_TX_IPV4 | PKT_TX_TCP_CKSUM
>> 
>> 
>> Did I miss any step?
>> 
>> 
>> Thanks in advance,
>> Tim
>> 
>Check that you have not got TX offloads disabled in your port configuration. If
>you pass in NULL for the rte_eth_txconf pointer on tx queue setup, then offloads
>will be disabled. To get offloads such as checksums to work, you need to explicitly
>set the flags to allow them. (Generally, this means just setting txqflags to 0)
>
>Regards,
>/Bruce
>