Accelerator-rich architectures employ IOMMUs to support unified virtual address, but researches show that they fail to meet the performance and energy requirements of accelerators. Instead of optimizing the speed/energy of IOMMU address translation, this work tackles the issue from a new perspective, eliminating the need for translation with an active forwarding (AF) mechanism that forwards input data of accelerators directly from the CPU cache to the scratchpad memory of the accelerator. Results show that on average, AF can provide 8% performance improvement compared to the state-of-the-art mechanism, hostPageWalk, and reduce 22.1% accelerator power.

To consider QoS for resource-limited mobile systems, we introduce a fast preemption mechanism on GPUs. First, we involve a dual-kernel execution model to support fine-grained preemption, and a resource allocation policy to avoid resource fragmentation problem. Second, we propose a preemption victim selection scheme to reduce the throughput overhead while satisfying a required preemption latency. Evaluations show that we can reach very close to the ideal preemption scheme within 2% difference in terms of deadline violations. Furthermore, on average we improve GPU resource utilization by 2.93× over prior technique during preemption.