On 09 Oct 2007 18:51:51 +0200 Andi Kleen <[EMAIL PROTECTED]> wrote: > David Miller <[EMAIL PROTECTED]> writes: > > > > 2) Switch the default qdisc away from pfifo_fast to a new DRR fifo > > with load balancing using the code in #1. I think this is kind > > of in the territory of what Peter said he is working on. > > Hopefully that new qdisc will just use the TX rings of the hardware > directly. They are typically large enough these days. That might avoid > some locking in this critical path. > > > I know this is controversial, but realistically I doubt users > > benefit at all from the prioritization that pfifo provides. > > I agree. For most interfaces the priority is probably dubious. > Even for DSL the prioritization will be likely usually done in a router > these days. > > Also for the fast interfaces where we do TSO priority doesn't work > very well anyways -- with large packets there is not too much > to prioritize. > > > 3) Work on discovering a way to make the locking on transmit as > > localized to the current thread of execution as possible. Things > > like RCU and statistic replication, techniques we use widely > > elsewhere in the stack, begin to come to mind. > > If the data is just passed on to the hardware queue, why is any > locking needed at all? (except for the driver locking of course) > > -Andi
I wonder about the whole idea of queueing in general at such high speeds. Given the normal bi-modal distribution of packets, and the predominance of 1500 byte MTU; does it make sense to even have any queueing in software at all? -- Stephen Hemminger <[EMAIL PROTECTED]> - 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
