This project adds Homa support to gRPC, so that gRPC applications can use Homa instead of TCP for transport.

• This project is still in a relatively early stage of development, but C++ support is functional as of November 2021. Next up is Java support.

• Please contact me if you have any problems; I'm happy to provide advice and support.

• The head is currently based on gRPC v. 1.57.0 (and there is a branch named grpc-1.57.0 that will track this version of gRPC). There are also branches grpc-1.43.0 and grpc-1.41.0, which represent the most recent code to work on those branches. Older branches are not actively maintained.

• Known limitations:

  • grpc_homa currently supports only insecure channels.

• Initial performance measurements show that short RPCs complete about 40% faster with Homa than with TCP (about 55 us round trip for Homa, vs. 90 us for TCP).

How to use grpc_homa

• You will need to download the Linux kernel driver for Homa. Compile it as described in that repo and install it on all the machines where you plan to use gRPC.

• Configure the Makefile as described in the comments at the top (sorry... I know this shouldn't need to be done manually).

• Type make. This will build libhoma.a, which you should link with your applications.

• When compiling your applications, use -I to specify this directory, then #include homa_client.h as needed for clients and #include homa_listener.h as needed for servers.

• On clients, pass HomaClient::insecureChannelCredentials() to grpc::CreateChannel instead of grpc::InsecureChannelCredentials() to create a channel that uses Homa. For an example of a simple but complete client, see test_client.cc.

• On servers, pass HomaListener::insecureCredentials() to grpc::AddListeningPort instead of grpc::InsecureServerCredentials(). For an example of a simple but complete server, see test_server.cc.

• Once you have done this, all your existing gRPC-based code should work just fine.