[emmericp]

Java reaches 52% of C speed in the benchmark game ("fastest measurement at the largest workload" data set, geometric mean), we reach 38%. Seems like our implementation is within a reasonable range for something that's usually not done in Java.

A full memory barrier is not required, but some languages only offer that. For example, go had the same problem. It's not a bottleneck because it goes to MMIO PCIe space which is super slow anyways (awaits a whole PCIe roundtrip).

And no, it obviously wasn't written by only one person but a team of 10.

No, we are not saying that we allocate for every packet. We say that we allocate 20 bytes on average per packet.

[altfredd]

Java support all sorts of memory barriers via VarHandles (see GET_OPAQUE/SET_OPAQUE). VarHandles can be created from contents of ByteBuffers:

https://docs.oracle.com/javase/9/docs/api/java/lang/invoke/M...