performance: slow than net/http with default setting

[hanjm]

https://github.com/plutov/benchmark-grpc-protobuf-vs-http-json is a benchmark repo about grpc-protobuf(Unary) vs http-json, it seems grpc-go slow than net/http with default setting in latest benchmark result at 2019.
i try to set InitialWindowSize=1<<30,InitialConnWindowSize=1<<30,WriteBufferSize=256 * 1024, ReadBufferSize=256 * 1024 both client and server, then grpc-go similar than net/http at 1 connection 1 concurrency regular scenario.

$ go test -bench . -benchmem -test.count 4
goos: darwin
goarch: amd64
BenchmarkGRPCProtobuf-8   	   10000	    109227 ns/op	    9829 B/op	     191 allocs/op
BenchmarkGRPCProtobuf-8   	   10000	    102425 ns/op	    9824 B/op	     191 allocs/op
BenchmarkGRPCProtobuf-8   	   10000	    101966 ns/op	    9823 B/op	     191 allocs/op
BenchmarkGRPCProtobuf-8   	   10000	    100819 ns/op	    9823 B/op	     191 allocs/op
BenchmarkHTTPJSON-8       	   10000	    103827 ns/op	    8904 B/op	     117 allocs/op
BenchmarkHTTPJSON-8       	   10000	    102093 ns/op	    8902 B/op	     117 allocs/op
BenchmarkHTTPJSON-8       	   10000	    100043 ns/op	    8903 B/op	     117 allocs/op
BenchmarkHTTPJSON-8       	   10000	    121196 ns/op	    8904 B/op	     117 allocs/op
PASS

related slow than net/http issue at 2015: #89 #108
related issue about window size adjust. #1043
related issue about buffer size adjust.#1569
related issue about performance. #586

[dfawley]

@hanjm the numbers you are showing don't appear to be significantly slower. Can you explain more what the numbers mean and how you are interpreting them? Also, running more iterations may show different results, or more operations per iteration may be helpful in reducing variance.

[hanjm]

hi @dfawley , as result of https://github.com/plutov/benchmark-grpc-protobuf-vs-http-json, with default transport settings, the conclusion is that

They are almost the same, HTTP+JSON is a bit faster and has less allocs/op.

Unary gRPC why slow than HTTP/1, it just counterintuitive and confusing, how to explain it?

[dfawley]

Unary gRPC why slow than HTTP/1, it just counterintuitive and confusing, how to explain it?

I can't explain this without fully understanding how these particular benchmarks work. This is a bit of an apples-to-oranges comparison, regardless, since gRPC has more features than HTTP/1+JSON (e.g. bi-directional streaming, multiple streams over a single connection, flow control). These features do have some cost, although we expect it to be a small one.

If you're interested in looking more, we have a benchmark directory in gRPC-go that contains a binary capable of running benchmarks with various parameters, which is what we use for our testing. There are also regular benchmark results available through our website. This link will take you directly there: https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5636470266134528.