What is this repository for?
sch_pi2: PI2 AQM (with dual queue option) module for Linux
iproute2-3.16.0: iproute2 package with added support for sch_pi2
PI2 AQM is both an extension, and a simplification of the PIE (PI-Enhanced AQM). It makes quite some heuristics unnecessary, while enabling it to control scalable (L4S = low loss, low latency and scalable) congestion controls (like DCTCP, TCP-Prague, ...). Both Reno/Cubic can be used in parallel with DCTCP, giving it the same throughput.
The DualQ option can be used to classify the L4S traffic in a priority low latency queue, enabling L4S's full low latency power. The drop/mark coupling makes sure that the flows are still fair (now only congestion window fair as, due to the different Q sizes, their RTT will be different).
How do I get set up?
PI2 AQM is implemented as a module. In order to use it, you need to either reinstall iproute2 package or use a local build of tc from iproute2. The files that should be added/changed and a patch are included in this repository. Currently only tested with iproute2 version 3.16.0.
Build iproute2 locally:
- download iproute2 package from https://www.kernel.org/pub/linux/utils/net/iproute2/
- apply patch or copy over the files manually
cd iproute2-3.16.0 && make
cd iproute2-3.16.0 && make install
Build sch_pi2 module:
cd sch_pi2 && make
cd sch_pi2 && make load
cd sch_pi2 && make unload
Add pi2 as a qdisc with a bottleneck of 40Mbps:
sudo tc qdisc del dev <interface> root
sudo tc qdisc add dev <interface> root handle 1: htb default 10
sudo tc class add dev <interface> parent 1: classid 1:10 htb rate 40Mbit ceil 40Mbit burst 1516
sudo tc qdisc add dev <interface> parent 1:10 pi2
or with the dualQ option:
sudo tc qdisc add dev <interface> parent 1:10 pi2 dualq
bison libdb-dev flex
Who do I talk to?
- Repo owner or admin
- Other community or team contact