On Thu, 2006-06-04 at 18:29 +0200, Patrick McHardy wrote: [..] > There are basically two possibilities how to implement this. The less > intrusive, but IMO more hackish one is to just handle this inside the > qdiscs that require this operation by not requeueing the packet to > the qdisc, but keeping a private reference somewhere. The disadvantage > is that this distorts statistics and estimators, the classful qdisc > would for example have more packets queued than the sum of all its > inner qdiscs. The other possibility is to introduce a ->peek operation > or a flag to ->dequeue and handle it within the reordering qdiscs. > I think we only need to implement it for non-classful (or single-class) > qdiscs, I can't imagine why anyone would add a scheduler as inner qdisc > to a different scheduler, at least with the current ones. > > Any preferences or suggestions? Otherwise I'll go with the second > possibility. >
The second scheme looks better. The other way (mod to the second scheme) is to have the dequeue "compensate for the last time" in the qdiscs i.e if you over/undershot the last time because you computed lets say a delay based on a packet which is no longer at the head of the queue then you take that into account as well; note this suggestion implies it is the non-work-conserving schedulers problem (which i think it is). i.e those schedulers need to be fixed with a new assumption that "the packet you got this time may not be the same as the last one you used to compute next-time-to-give-an-skb". cheers, jamal - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
