Hi Ben, Darrell, It sounds like the general feeling is that any kind of tc pre-processing is not worth it and the existing egress queing/QoS facilities should suffice.
Thanks for your comments. /Billy > -----Original Message----- > From: Ben Pfaff [mailto:b...@ovn.org] > Sent: Thursday, April 13, 2017 7:47 PM > To: O Mahony, Billy <billy.o.mah...@intel.com> > Cc: ovs-discuss@openvswitch.org > Subject: Re: [ovs-discuss] prioritizing latency-sensitive traffic > > I don't know how much more OVS can contribute to this than it already does. > By the time that OVS has classified a packet to the extent that is necessary > to > determine that it should be handled with a high priority, OVS has already > done most of the work that it does on a packet. [[BO'M]] I'm investigating how I could go about classifying packets before the main The work to transmit the > packet is not part of OVS's job, it is the job of the driver, and at most OVS > can > mark the packet with a priority or a queue. OVS can already do that. So the > usual answer is that it's a matter of configuring QoS in the driver to do what > the user wants. > > On Mon, Apr 10, 2017 at 09:30:12AM +0000, O Mahony, Billy wrote: > > Hi Everybody, > > > > I just wanted to reflag this discussion below about possible methods of > how to prioritize certain types of traffic handled by OVS. > > > > By prioritize I mean either or both of: > > a) 'priority' packets are sent to their destination port faster than > > other packets > > b) in an overloaded situation the switch drops non-prioritized packets > rather than prioritized packets. > > > > Also just to be clear I am discussing kernel ovs here. Also I'm looking at > doing this without writing new code - ie is it possible and if so how is it > configured using existing OVS. > > > > Thanks again, > > Billy. > > > > > -----Original Message----- > > > From: ovs-discuss-boun...@openvswitch.org [mailto:ovs-discuss- > > > boun...@openvswitch.org] On Behalf Of O Mahony, Billy > > > Sent: Friday, November 25, 2016 5:04 PM > > > To: ovs-discuss@openvswitch.org > > > Subject: [ovs-discuss] prioritizing latency-sensitive traffic > > > > > > Hi, > > > > > > I have been performing tests investigating latency profiles of > > > low-bandwidth time-sensitive traffic when the system is busy with > 'normal' traffic. > > > Unsurprisingly the latency-sensitive traffic is affected by the > > > normal traffic and has basically the same latency profile as the normal > traffic. > > > > > > I would like to be able to perform prioritization of traffic as some > > > protocols such as PTP would benefit greatly from having it's packets 'jump > the queue'. > > > > > > From skimming the documentation it looks that ingress QoS offers > > > only policing (rate-limiting). Is this actually the case or maybe > > > I'm not looking in the right place? > > > > > > But if so, I am looking at some alternatives: > > > > > > a) create two separate egress ports and have PTP listen on one port, > > > everything else listen on the other port and use normal forwarding > > > rules to send PTP traffic incoming from eth0 to it's own port. Something > like: > > > > > > other apps ptp_daemon > > > + + > > > + + > > > if_norm if_ptp > > > + + > > > | | > > > | | > > > ++------------++ > > > | | > > > | ovs | > > > | | > > > +-----+--------+ > > > | > > > + > > > eth0 > > > > > > b) create prioritized queues on a port and use match and actions > > > such as > > > set_queue(queue) and enqueue(port, queue) on ingress traffic to > > > forward the PTP traffic to the higher priority queue. However I > > > think queue priority for this case only relates to which queue get > > > to consume the bandwidth of the port first and not about changing > > > the order in which the packets egress the port. > > > > > > c) Or perhaps I can re-use tc PRIO or CBQ qdiscs by passing all > > > traffic to tc first before ovs? > > > > > > other apps > > > | > > > | > > > if_norm > > > + > > > | > > > | > > > +--------------+ > > > | | > > > | ovs | > > > | | > > > +-----+--------+ > > > | > > > | > > > tc ----- if_ptp ---- ptp_daemon > > > + > > > eth0 > > > > > > Any thoughts, ideas or clarifications most welcome. > > > > > > Thanks, > > > Billy. > > > > > > _______________________________________________ > > > discuss mailing list > > > disc...@openvswitch.org > > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss > > _______________________________________________ > > discuss mailing list > > disc...@openvswitch.org > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss _______________________________________________ discuss mailing list disc...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
