Do you have more information on the results obtained? any information on how to enable NUMA-aware code ?
The r6i.metal instance says up to 50 Gbps on Network bandwidth: https://aws.amazon.com/ec2/instance-types/r6i/
The r6i.metal instance says up to 50 Gbps on Network bandwidth: https://aws.amazon.com/ec2/instance-types/r6i/
You could go extreme and start pinning your threads to specific CPUs to tune the code manually instead of relying on the kernel if you know memory bandwidth is extremely important and you won't have much CPU contention to worry about in terms of getting work scheduled in a timely manner.
All that being said, you typically also need to design your application from the ground up to be NUMA aware to take full advantage so that you can set up your allocations to happen on the right zone & whatnot.