As far as I know, L2FWD only uses 1 core for all RX/TX, for all queues, but for ip_pipeline, you may use more cores. A simple question, are you using 1core in ip_pipeline or l3fwd test?
> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Royce Niu > Sent: Thursday, December 22, 2016 9:36 PM > To: Richardson, Bruce <bruce.richard...@intel.com> > Cc: Royce Niu <royce...@gmail.com>; dev@dpdk.org; Dumitrescu, Cristian > <cristian.dumitre...@intel.com> > Subject: Re: [dpdk-dev] Why IP_PIPELINE is faster than L2FWD > > Dear Bruce, > > Thanks for your kind explanation. > > I will try to follow your suggestion and see the source code. > > On Thu, Dec 22, 2016 at 9:25 PM, Bruce Richardson < > bruce.richard...@intel.com> wrote: > > > On Thu, Dec 22, 2016 at 08:48:50PM +0800, Royce Niu wrote: > > > But, actually, L3FWD of IP_PIPELINE is also faster than stock L2FWD, > > which > > > also modifies mac addr. How can explain this? > > > > > > Actually, I want to know why IP_PIPELINE is much faster and I can > > > learn from IP_PIPELINE and make our own program. > > > > > > But, the documentation of that is not detailed enough. if it is > > > possible, could you tell me where is the key to boost? Thanks! > > > > > > > Adding Cristian as IP Pipeline maintainer. > > > > A lot of tuning work went into IP Pipeline and the table and port > > libraries it uses, so I'm not sure that there is just one or two key > > changes which give it such good performance. L2 forward just hasn't > > had the same level of tuning and, while performing well, is also > > simplified to make it understandable as an example. Contrast the code > > in l2fwd against equivalent vector code in l3fwd-lpm* files e.g. > l3fwd_lpm_sse.h. > > The latter is very high performing, the former is more readable. > > > > Regards, > > /Bruce > > > > > On Thu, Dec 22, 2016 at 7:15 PM, Bruce Richardson < > > > bruce.richard...@intel.com> wrote: > > > > > > > On Thu, Dec 22, 2016 at 12:18:12AM +0800, Royce Niu wrote: > > > > > Hi all, > > > > > > > > > > I tested default L2FWD and IP_PIPELINE (pass-through). The > > throughput of > > > > > IP_PIPELINE is higher immensely. > > > > > > > > > > There are only two virtual NICs in KVM. The experiment is just > > > > > moving packet from vNIC0 to vNIC1. I think the function is so > > > > > simple. Why > > L2FWD > > > > > is much slower? > > > > > > > > > > How can I improve L2FWD, to make L2FWD faster? > > > > > > > > > Is IP_PIPELINE in passthrough mode modifying the packets? L2FWD > > > > swaps the mac addresses on each packet as it processes them, which > > > > can slow > > it > > > > down. L2FWD is also more an example of how the APIs work than > > > > anything else. For fastest possible port-to-port forwarding, > > > > testpmd should give the highest performance. > > > > > > > > /Bruce > > > > > > > > > > > > > > > > -- > > > Regards, > > > > > > Royce > > > > > > -- > Regards, > > Royce
