On Fri, Aug 28, 2020 at 10:51 AM S.V.R.Anand <anand...@iisc.ac.in> wrote: > > There is an active Internet draft "Packet Delivery Deadline time in > 6LoWPAN Routing Header" > (https://datatracker.ietf.org/doc/draft-ietf-6lo-deadline-time/) which > is presently in the RFC Editor queue and is expected to become an RFC in > the near future. I happened to be one of the co-authors of this draft. > The main objective of the draft is to support time sensitive industrial > applications such as Industrial process control and automation over IP > networks. While the current draft caters to 6LoWPAN networks, I would > assume that it can be extended to carry deadline information in other > encapsulations including IPv6. > > Once the packet reaches the destination at the network stack in the > kernel, it has to be passed on to the receiver application within the > deadline carried in the packet because it is the receiver application > running in user space is the eventual consumer of the data. My mail below is > for > ensuring passing on the packet sitting in the socket interface to the > user receiver application process in a timely fashion with the help of > OS scheduler. Since the incoming packet experieces variable delay, the > remaining time left before deadline approaches too varies. There should > be a mechanism within the kernel, where network stack needs to > communicate with the OS scheduler by letting the scheduler know the > deadline before user application socket recv call is expected to return. > > Anand > > > On 20-08-28 10:14:13, Eric Dumazet wrote: > > > > > > On 8/27/20 11:45 PM, S.V.R.Anand wrote: > > > Hi, > > > > > > In the control loop application I am trying to build, an incoming message > > > from > > > the network will have a deadline before which it should be delivered to > > > the > > > receiver process. This essentially calls for a way of scheduling this > > > process > > > based on the deadline information contained in the message. > > > > > > If not already available, I wish to write code for such run-time > > > ordering of > > > processes in the earlist deadline first fashion. The assumption, however > > > futuristic it may be, is that deadline information is contained as part > > > of the > > > packet header something like an inband-OAM. > > > > > > Your feedback on the above will be very helpful. > > > > > > Hope the above objective will be of general interest to netdev as well. > > > > > > My apologies if this is not the appropriate mailing list for posting this > > > kind > > > of mails. > > > > > > Anand > > > > > > > Is this described in some RFC ? > > > > If not, I guess you might have to code this in user space.
Could ingress redirect to an IFB device with FQ scheduler work for ingress EDT? With a BPF program at ifb device egress hook to read the header and write skb->tstamp.
