R2P2 - Request Response Pair Protocol

R2P2 is a UDP-based transport protocol specifically targetting microsecond-scale RPCs. R2P2 exposes pairs of requests and responses and allows efficient and scalable RPC routing by separating the RPC target selection from request and reply streaming.

The existing R2P2 implementation supports both a Linux-based implementation mostly for testing, and a DPDK-based implementation for performance.

Building R2P2

To build and run R2P2 you need to build DPDK and prepare the machine to run an R2P2 application. The init.sh fetches and builds DPDK, allocates hugepages, and configures the NIC for use with DPDK. Specifically:

export DEVICE_NAME=<your-interface-name>
export PCI_ADDR=<the-devive-pci-address>
git submodule update --init --recursive
make dpdk
make
./init.sh

Code Structure

The repository is structured as follows:

• r2p2 This folder holds the main R2P2 implementation used both for Linux on top of UDP sockets and on top of DPDK.

• netstack This folder holds a mininal networking stack on top of DPDK implementing Ethernet, IP, UDP, ICMP, and ARP layers.

• linux-apps This folder holds sample linux server and client applications as examples.

• dpdk-apps This folder holds sample dpdk server applications and the software R2P2 router.

• r2p2.conf.sample R2P2 expects to find a configuration file under /etc/r2p2.conf. We provide a sample configuration file. Important! Make sure you provide a valid configuration file at the right location before running any examples.

Run R2P2 examples

After building the code you can run the following echo examples. The client sends 10 requests to the server and the server echoes back the received payload.

Linux client - Linux server

On the server machine run:

./linux-apps/linux_server # this will run an R2P2 echo server on port 8000

On the client machine run:

./linux-apps/linux_client <server_ip> 8000

Linux client - DPDK server

On the server machine run:

sudo ./dpdk-apps/r2p2-echo -l 0 # this will run a single-threaded R2P2 server

On the client machine run:

./linux-apps/linux_client <server_ip> 8000

Linux client - Router - Server

In this example you are going to use the R2P2 router between the R2P2 client and the R2P2 server.

For a Linux server:

make -C linux-apps/ WITH_ROUTER=1
./linux-apps/linux_server

For a DPDK server:

sudo ./dpdk-apps/r2p2-echo-fdir -l 0

To run the router:

sudo ./dpdk-apps/r2p2-router -l 0,2 -- <server_ip>:8000:1 0 rr

On the client machine run:

./linux-apps/linux_client <router_ip> 8000

R2P2 Router

The R2P2 router can run either as a software middlebox or as part of a Tofino ASIC. In this repository we only include the software DPDK implementation.

Software Router options

Usage: ./router -l 0,2 -- <target_ip:base_port:count,...> <per_queue_slots> <rand|rr|fc>

The software router runs on 2 cores (0,2) and implements 3 different policies: rand for random selections, rrfor round-robin, and fc for JBSQ. The takes a comaseparated list of servers. For each server provide the target ip, the base port, and how many ports this server exposes separated by colon. For example 10.0.0.1:8000:2 registers 2 queues to the R2P2 router both at 10.0.0.1, one at 8000, and one at 8001. The per_queue_slots arguement is only useful in the JBSQ(n) case and it's the n. For the other policies, this argument should be 0.

HovercRaft

To run R2P2 with the HovercRaft extension (See the Eurosys paper for more details) you need to build with WITH_RAFT=1 as described in the HovercRaft repo.

Also, you need to configure your r2p2.conf accirdingly. Specifically, you need to add raft peers and the used multicast groups as in the r2p2.conf.sample.

HovercRaft++

For HovercRaft++ (in-network acceleration for HovercRaft) you need to also add the switch peer. So, in the raft section of your r2p2.conf you need to have an even number of peers, and the last one corresponds to the switch.

P4 Source Code

For the P4 source code for JBSQ and HovercRaft++ please contact marios.kogias@epfl.ch.