On Tue, Mar 22, 2022 at 10:38 AM Templin (US), Fred L <fred.l.temp...@boeing.com> wrote: > > Tom, see below: > > > -----Original Message----- > > From: Tom Herbert [mailto:t...@herbertland.com] > > Sent: Tuesday, March 22, 2022 10:00 AM > > To: Templin (US), Fred L <fred.l.temp...@boeing.com> > > Cc: Eggert, Lars <l...@netapp.com>; int-area@ietf.org > > Subject: Re: [Int-area] IP Parcels improves performance for end systems > > > > On Tue, Mar 22, 2022 at 7:42 AM Templin (US), Fred L > > <fred.l.temp...@boeing.com> wrote: > > > > > > Lars, I did a poor job of answering your question. One of the most > > > important aspects of > > > > > > IP Parcels in relation to TSO and GSO/GRO is that transports get to use a > > > full 4MB buffer > > > > > > instead of the 64KB limit in current practices. This is possible due to > > > the IP Parcel jumbo > > > > > > payload option encapsulation which provides a 32-bit length field instead > > > of just a 16-bit. > > > > > > By allowing the transport to present the IP layer with a buffer of up to > > > 4MB, it reduces > > > > > > the overhead, minimizes system calls and interrupts, etc. > > > > > > > > > > > > So, yes, IP Parcels is very much about improving the performance for end > > > systems in > > > > > > comparison with current practice (GSO/GRO and TSO). > > > > Hi Fred, > > > > The nice thing about TSO/GSO/GRO is that they don't require any > > changes to the protocol as just implementation techniques, also > > they're one sided opitmizations meaning for instance that TSO can be > > used at the sender without requiring GRO to be used at the receiver. > > My understanding is that IP parcels requires new protocol that would > > need to be implemented on both endpoints and possibly in some routers. > > It is not entirely true that the protocol needs to be implemented on both > endpoints . Sources that send IP Parcels send them into a Parcel-capable path > which ends at either the final destination or a router for which the next hop > is > not Parcel-capable. If the Parcel-capable path extends all the way to the > final > destination, then the Parcel is delivered to the destination which knows how > to deal with it. If the Parcel-capable path ends at a router somewhere in the > middle, the router opens the Parcel and sends each enclosed segment as an > independent IP packet. The final destination is then free to apply GRO to the > incoming IP packets even if it does not understand Parcels. > > IP Parcels is about efficient shipping and handling just like the major online > retailer service model I described during the talk. The goal is to deliver the > fewest and largest possible parcels to the final destination rather than > delivering lots of small IP packets. It is good for the network and good for > the end systems both. If this were not true, then Amazon would send the > consumer 50 small boxes with 1 item each instead of 1 larger box with all > 50 items inside. And, we all know what they would choose to do. > > > Do you have data that shows the benefits of IP Parcels in light of > > these requirements? > > I have data that shows that GSO/GRO is good for packaging sizes up to 64KB > even if the enclosed segments will require IP fragmentation upon transmission. > The data implies that even larger packaging sizes (up to a maximum of 4MB) > would be better still. >
Fred, You seem to be only looking at the problem from a per packet cost point of view. There is also per byte cost, particularly in the computation of the TCP/UDP checksum. The cost is hidden in modern implementations by checksum offload, and for segmentation offload we have methods to preserve the utility of checksum offload. IP parcels will have to also leverage checksum offload, because if the checksum is not offloaded then the cost of computing the payload checksum in CPU would dwarf any benefits we'd get by using segments larger than 64K. Tom > Fred > > > Thanks, > > Tom > > > > > > > > > > > > > > Thanks - Fred > > > > > > _______________________________________________ > > > Int-area mailing list > > > Int-area@ietf.org > > > https://www.ietf.org/mailman/listinfo/int-area _______________________________________________ Int-area mailing list Int-area@ietf.org https://www.ietf.org/mailman/listinfo/int-area
