RISO: Relaxed network-on-chip isolation for cloud processors

Cloud service providers use workload consolidation technique in many-core cloud processors to optimize system utilization and augment performance for ever extending scale-out workloads. Performance isolation usually has to be enforced for the consolidated workloads sharing the same many-core resources. Networks-on-chip (NoC) serves as a major shared resource, also needs to be isolated to avoid violating performance isolation. Prior work uses strict network isolation to fulfill performance isolation. However, strict network isolation either results in low consolidation density, or complex routing mechanisms which indicates prohibitive high hardware cost and large latency. In view of this limitation, we propose a novel NoC isolation strategy for many-core cloud processors, called relaxed isolation (RISO). It permits underutilized links to be shared by multiple applications, at the same time keeps the aggregated traffic in check to enforce performance isolation. The experimental results show that the consolidation density is improved more than 12% in comparison with previous strict isolation scheme, meanwhile reducing network latency by 38.4% on average.