There has been a lot going on behind the lines, however, and some major announcements are imminent on ways to really fix bufferbloat. But I wanted to take a moment to acknowledge other important work in the meanwhile so they do not get lost in the noise, and to get your juices flowing.
- First off, Linux 3.3 shipped with BQL (byte queue limits) done by Tom Herbert of Google. This is good stuff: finally, the transmit rings in Linux network device drivers won’t cause hundreds of packets of buffering.
- Dave Taht has had good success prototyping in CeroWrt a combination of Linux’s SFQ and RED to good effect: SFQ ensures decent sharing among short lived interactive flows which receive preference to long lived elephant flow TCP sessions. As transient bufferbloat and TSO/GSO GRO/LRO smart NIC’s make clear, no comprehensive solutions for achieving good latency are possible without some sort of “fair” queuing and/or classification. As in all RED based AQM algorithms, tuning SFQRED is a bitch and a better AQM is badly needed; news at 11 on that front. CeroWrt is approaching its first release with all sorts of nice features and I’ll blog about it when it’s soup. In the meanwhile, adventurers can find all they want to know about CeroWrt at the links here.
- The DOCSIS changes to mitigate bufferbloat in cable modems continues on its way. While I haven’t checked in to see when deployment really starts (driven by modification to cable carrier deployment systems), we should see this major improvement later this year.
So there is hope. Really… Stay tuned…