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With the increase in GPU register file (RF) size, its power consumption has also increased. Since RF exists at the highest level in cache hierarchy, designing it with memories with high write latency/energy (e.g., spin transfer torque RAM) can lead to large energy loss. In this paper, we present an spin orbit torque RAM (SOT-RAM) based RF design which provides higher energy efficiency than SRAM and STT-RAM RFs while maintaining performance same as that of SRAM RF. To further improve energy efficiency of SOT-RAM based RF, we propose avoiding redundant bit-writes to RF. Compared to SRAM RF, SOT-RAM RF saves 18.6% energy and by using our technique for avoiding redundant writes, the energy saving can be increased to 44.3%, without harming performance. 

Dynamic parallelism (DP) is a promising feature for GPUs, which allows on-demand spawning of kernels on the GPU without any CPU intervention. However, this feature has two major drawbacks. First, the launching of GPU kernels can incur significant performance penalties. Second, dynamically-generated kernels are not always able to efficiently utilize the GPU cores due to hardware-limits. To address these two concerns cohesively, we propose SPAWN, a runtime framework that controls the dynamically-generated kernels, thereby directly reducing the associated launch overheads and queuing latency. Moreover, it allows a better mix of dynamically-generated and original (parent) kernels for the scheduler to effectively hide the remaining overheads and improve the utilization of the GPU resources. Our results show that, across 13 benchmarks, SPAWN achieves 69% and 57% speedup over the flat (non-DP) implementation and baseline DP, respectively. 

Modern graphics processing units (GPUs) are using increasingly larger register file (RF) which occupies a large fraction of GPU core area and is very frequently accessed. This makes RF vulnerable to soft-errors (SE). In this paper, we present two techniques for improving SE resilience of GPU RF. First, we propose compressing the RF values for reducing the number of vulnerable bits. We leverage value similarity and the presence of narrow-width values to perform compression at warp or thread-level, respectively. Second, we propose selective hardening to design a portion of register entry with SE immune circuits. By collectively using these techniques, higher resilience can be provided with lower overhead. Without hardening, our warp and thread-level compression techniques bring 47.0% and 40.8% reduction in SE vulnerability, respectively.