> On Sep 11, 2019, at 2:07 AM, wei_sky2...@163.com wrote: > > On Tue, Sep 10, 2019 at 12:44 AM, Christian Hopps wrote: > UTSL > Thank you for reply。 > In our scenario，we use the Intel ‘s DDP feature to hash different GTP > packets into different threads。And We want the GTP packets from the same UE > to be hashed on the same thread，DDP can‘t implement this function。 > So we consider using the Handoff mechanism 。But We still have some doubts. > （1） We know VPP ensure efficiency by deal one group packets by the same > thread's nodes，if we use handoff ，how much does this mechanism affect > efficiency?Or is there any other mechanism to meet our requirements?
Actually, the fundamental efficiency is based on I-cache utilization, AFAICT. By processing a bunch of packets (the vector of packets, i.e., the node's frame) using the same smallish bit of code (the node function) the i-cache is only invalidated/reloaded when moving from node to node and so it executes very quickly over a large set of packets. In addition a very common design pattern inside a VPP node function is to loop on a clump of packets, while prefeching the next clump (which happens in parallel) so that the load from RAM to D-cache hit is hopefully minimized. Together these optimizations work regardless of which thread is processing the vector of packets. > （2）If we use Handoff，Which method is better: > a) Dealing GTP packet RSS without using devices， use software > RSS，use one Thread receive All packets，then handoff to other threads > b) Dealing GTP packet RSS with using devices, when the thread > receive packet, determine if the current thread need to deal this packet，if > not，handoff to other thread。 I think you'll need to figure this out yourself (or maybe someone else can help). I'm myself writing an application and learning what works and doesn't work right now. :) Thanks, Chris. > > -=-=-=-=-=-=-=-=-=-=-=- > Links: You receive all messages sent to this group. > > View/Reply Online (#13949): https://lists.fd.io/g/vpp-dev/message/13949 > Mute This Topic: https://lists.fd.io/mt/34077019/1826170 > Group Owner: vpp-dev+ow...@lists.fd.io > Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [cho...@chopps.org] > -=-=-=-=-=-=-=-=-=-=-=-
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