grpc 1.62 performance regression compared with 1.55

[Yunhao Bai]

Recently, we are performing performance test on gRPC server receiving unary RPC request. We are performing the test on a 48 core server machine with CPU E5-2650 2.20gHZ. We see that after we upgrade the grpc version from 1.55 to 1.62, we see a performance drop pretty large:

We followed the qps way to implement the server, and the client will send unary rpc on a fix interval. we check the RPC response time for all the unary requests. See code here:

perf test repo

The throughput for grpc 1.62 should be similar to that of grpc 1.55 (with default-executor). But there is about 20% throughput drop compared with grpc 1.55 (with default-executor). Why there is a large performance drop when the server is saturated on grpc 1.55?

[Eugene Ostroukhov]

Please file an issue on GitHub for the team to take a look.