Re: [dpdk-dev] generic load balancing

["François-Frédéric Ozog" <ff@ozog.com>]

Can we (as a community) be leading the way for the NIC vendors?

I mean, a few years ago I had the discussion with Chelsio to solve MPLS and GTP load balancing.
They were happy to integrate the "requirements" in the roadmap....

So could we build a list of such "requirements" and publish it? NIC vendors are looking ways to differentiate from one another, so I assume this may help us get what we want.

In addition to the NIC requirements we may polish an API to control those features in a standard way from DPDK.


François-Frédéric


> -----Message d'origine-----
> De : dev [mailto:dev-bounces@dpdk.org] De la part de Prashant Upadhyaya
> Envoyé : vendredi 6 décembre 2013 05:04
> À : 吴亚东; Thomas Monjalon
> Cc : dev@dpdk.org
> Objet : Re: [dpdk-dev] generic load balancing
> 
> Hi,
> 
> Regarding this point –
> 
> If intel supports round robin distribution of packets in the same flow,
> Intel needs to provide some way like Cavium's SSO(tag switch) to maintain
> packet order in the same flow. And it is hard to do so because intel's cpu
> and nic are decoupled
> 
> My main submission is – I understand there are issues like the above and
> ooo stuff you pointed out.
> But that is for the usecase implementer to solve in software logic. The
> equivalent of tag switch can be attempted to be developed in the software
> if the usecase so desires.
> But atleast ‘give’ the facility in the NIC to fan out on round robin on
> queues.
> Somehow we are trying to find out reasons why we should not have it.
> I am saying, give it in the NIC and let people use it in innovative ways.
> People who don’t want to use it can always have the choice to not use it.
> 
> Regards
> -Prashant
> 
> 
> From: 吴亚东 [mailto:ydwoo0722@gmail.com]
> Sent: Friday, December 06, 2013 7:47 AM
> To: Thomas Monjalon
> Cc: Michael Quicquaro; Prashant Upadhyaya; dev@dpdk.org
> Subject: Re: [dpdk-dev] generic load balancing
> 
> RSS is a way to distribute packets to multi cores while packets order in
> the same flow still get maintained.
> 
> Round robin distribution of packets may cause ooo(out of order) of packets
> in the same flow.
> We also meet this problem in ipsec vpn case.
> The tunneled packets are rss to the same queue if they are on the same
> tunnel.
> But if we dispatch the packets to the other cores to process, ooo packets
> may occur and tcp performance may be greatly hurt.
> 
> If you enable rss on udp packets and some udp packets are ip fragmented,
> rss of udp fragments(hash only calculated from ip addr) may be different
> fom rss of udp non-fragment packets(hash with information of udp ports),
> ooo may occur too.
> So in kernel driver disables udp rss by default.
> 
> If intel supports round robin distribution of packets in the same flow,
> Intel needs to provide some way like Cavium's SSO(tag switch) to maintain
> packet order in the same flow. And it is hard to do so because intel's cpu
> and nic are decoupled.
> 
> 
> 
> 
> 2013/12/6 Thomas Monjalon
> <thomas.monjalon@6wind.com<mailto:thomas.monjalon@6wind.com>>
> Hello,
> 
> 05/12/2013 16:42, Michael Quicquaro :
> > This is a good discussion and I hope Intel can see and benefit from it.
> Don't forget that this project is Open Source.
> So you can submit your patches for review.
> 
> Thanks for participating
> --
> Thomas
> 
> 
> 
> 
> 
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