> From: Pavan Nikhilesh [mailto:pbhagavat...@caviumnetworks.com] > Sent: Wednesday, January 10, 2018 8:01 PM > To: Van Haaren, Harry <harry.van.haa...@intel.com>; > jerin.ja...@caviumnetworks.com; santosh.shu...@caviumnetworks.com; Eads, > Gage <gage.e...@intel.com>; hemant.agra...@nxp.com; nipun.gu...@nxp.com; Ma, > Liang J <liang.j...@intel.com> > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v3 08/12] app/eventdev: add pipeline queue > test > > Hi Harry, > > Thanks for the review. > > On Wed, Jan 10, 2018 at 04:38:35PM +0000, Van Haaren, Harry wrote: > > > From: Pavan Nikhilesh [mailto:pbhagavat...@caviumnetworks.com] > > > Sent: Wednesday, January 10, 2018 2:52 PM > > > To: jerin.ja...@caviumnetworks.com; santosh.shu...@caviumnetworks.com; > Van > > > Haaren, Harry <harry.van.haa...@intel.com>; Eads, Gage > > > <gage.e...@intel.com>; hemant.agra...@nxp.com; nipun.gu...@nxp.com; Ma, > > > Liang J <liang.j...@intel.com> > > > Cc: dev@dpdk.org; Pavan Nikhilesh <pbhagavat...@caviumnetworks.com> > > > Subject: [dpdk-dev] [PATCH v3 08/12] app/eventdev: add pipeline queue > test > > > > > > This is a pipeline queue test case that aims at testing the following: > > > 1. Measure the end-to-end performance of an event dev with a ethernet > dev. > > > 2. Maintain packet ordering from Rx to Tx. > > > > > > The pipeline queue test configures the eventdev with Q queues and P > ports, > > > where Q is (nb_ethdev * nb_stages) + nb_ethdev and P is nb_workers. > > > > Why (nb_ethdev * nb_stages) number of Queues? > > > > I had expected if the test is for eventdev with Q queues, P ports, that > that Q number of stages is all that is required, (possibly with +1 for TX > queue, iirc some HW doesn't require the TX Queue). > > > > Am I missing something here? I've left the code snippet I don't understand > below. > > > > The idea is to reduce the load on ingress event queue (mapped to ethernet Rx > queue) > by splitting the traffic across event queues for each ethernet device. > > for example, nb_stages = 2 and nb_ethdev = 2 then > > nb_queues = (2 * 2) + 2 = 6 (non atq) > stride = 3 (nb_stages + 1 used for directing each ethernet dev traffic > into a specific event queue) > > queue id's 0,1,2,3,4,5 > > This allows us to direct the traffic from eth dev0 to event queue 0 and dev1 > to > queue 3 based on the stride (dev_id * stride). This intern forms two > pipelines > ethdev0 0->1->2->tx > ethdev1 3->4->5->tx > > In the absence of this both ethdev0 and ethdev1 would have to inject to 0th > queue and this leads to more congestion as the number of ethernet devices > increase. > > Hope this clears things up.
Ah ok, two parallel pipelines use-case. Makes sense, thanks for explaining. Acked-by: Harry van Haaren <harry.van.haa...@intel.com> <snip>
