As a word of advice -- you are almost certainly wasting your time writing a load balancer. There are close to zero cases where someone can legitimately justify such an exercise.
In any case, your benchmark is flawed (as virtually all benchmarks are). The reason Go the client is slower is because it tries to pervasively "thread" via the M:N scheduler -- every wait check causes it to yield the actual thread and switch goroutine, creating a large amount of overhead. The Scala cases, on the other hand, is dramatically more limited and will not yield this overhead.
The Go server does not have this fault, and is likely top performance. And aren't we talking about a server anyways?
Now as to the client, while we could naively criticize M:N scheduling based upon this, try giving it a more realistic workload (unless you seriously plan on load balancing pongs): Instead of ping/pong, return larger lengths of data preferably over actual network connections (not localhost) - e.g. 32KB.
The Go client will catch up if not shoot into the lead. M:N scheduling is optimal for most real-world workloads, though it is less optimal for spin-off-a-million-goroutines that do nothing type tests.
This is not a test of TCP overhead, or a realistic test, but instead demonstrates the small overhead of goroutines when you give each a minuscule amount of wait work.
Edit: Go has e.g. net.Dial("tcp", "localhost:1201") and as someone pointed out elsewhere for a more accurate bench in both clients why not use the numerical address instead?
In any case, your benchmark is flawed (as virtually all benchmarks are). The reason Go the client is slower is because it tries to pervasively "thread" via the M:N scheduler -- every wait check causes it to yield the actual thread and switch goroutine, creating a large amount of overhead. The Scala cases, on the other hand, is dramatically more limited and will not yield this overhead.
The Go server does not have this fault, and is likely top performance. And aren't we talking about a server anyways?
Now as to the client, while we could naively criticize M:N scheduling based upon this, try giving it a more realistic workload (unless you seriously plan on load balancing pongs): Instead of ping/pong, return larger lengths of data preferably over actual network connections (not localhost) - e.g. 32KB.
The Go client will catch up if not shoot into the lead. M:N scheduling is optimal for most real-world workloads, though it is less optimal for spin-off-a-million-goroutines that do nothing type tests.
This is not a test of TCP overhead, or a realistic test, but instead demonstrates the small overhead of goroutines when you give each a minuscule amount of wait work.