Re: [dpdk-dev] about rx checksum flags

["Chandran, Sugesh" <sugesh.chandran@intel.com>]

Regards
_Sugesh


> -----Original Message-----
> From: Olivier Matz [mailto:olivier.matz@6wind.com]
> Sent: Friday, June 3, 2016 1:43 PM
> To: Chandran, Sugesh <sugesh.chandran@intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Stephen Hemminger
> <stephen@networkplumber.org>
> Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>; dev@dpdk.org; Richardson,
> Bruce <bruce.richardson@intel.com>; Adrien Mazarguil
> <adrien.mazarguil@6wind.com>; Tan, Jianfeng <jianfeng.tan@intel.com>
> Subject: Re: [dpdk-dev] about rx checksum flags
> 
> Hi,
> 
> On 06/02/2016 09:42 AM, Chandran, Sugesh wrote:
> >>>> Do you also suggest to drop IP checksum flags?
> >>> > >
> >>> > > IP checksum offload is mostly useless. If application needs to
> >>> > > look at IP, it can do whole checksum in very few instructions,
> >>> > > the whole header is in the same cache line as src/dst so the HW
> >>> > > offload is really no
> >> > help.
> >>> > >
> > [Sugesh] The checksum offload can boost the tunneling performance in
> OVS.
> > I guess the IP checksum also important as L4. In some cases, UDP
> > checksum is zero and no need to validate it. But Ip checksum is
> > present on all the packets and that must be validated all  the time.
> > At higher packet rate, the ip checksum offload can offer slight performance
> improvement. What do you think??
> >
> 
> Agree, in some situations (and this is even more true with packet types /
> smartnics), the application could process without accessing the packet data if
> we keep the IP cksum flags.
[Sugesh] True, If that's the case, Will you considering to implement IP
checksum flags as well along with L4?
As you said , this will be useful when we offload packet lookup itself into the NICs(May be
when using Flow director) ? 



> 
> Regards,
> Olivier