Locality-Aware CTA Scheduling for Gaming Applications

The compute work rasterizer or the GigaThread Engine of a modern NVIDIA GPU focuses on maximizing compute work occupancy across all streaming multiprocessors in a GPU while retaining design simplicity. In this article, we identify the operational aspects of the GigaThread Engine that help it meet those goals but also lead to less-than-ideal cache locality for texture accesses in 2D compute shaders, which are an important optimization target for gaming applications. We develop three software techniques, namely LargeCTAs , Swizzle , and Agents , to show that it is possible to effectively exploit the texture data working set overlap intrinsic to 2D compute shaders. We evaluate these techniques on gaming applications across two generations of NVIDIA GPUs, RTX 2080 and RTX 3080, and find that they are effective on both GPUs. We find that the bandwidth savings from all our software techniques on RTX 2080 is much higher than the bandwidth savings on baseline execution from inter-generational cache capacity increase going from RTX 2080 to RTX 3080. Our best-performing technique, Agents , records up to a 4.7% average full-frame speedup by reducing bandwidth demand of targeted shaders at the L1-L2 and L2-DRAM interfaces by 23% and 32%, respectively, on the latest generation RTX 3080. These results acutely highlight the sensitivity of cache locality to compute work rasterization order and the importance of locality-aware cooperative thread array scheduling for gaming applications.

The Impact of Automated Vehicles on Traffic Flow and Road Capacity on Urban Road Networks

Automated vehicles (AVs) are believed to have great potential to improve the traffic capacity and efficiency of the current transport systems. Despite positive findings of the impact of AVs on traffic flow and potential road capacity increase for highways, few studies have been performed regarding the impact of AVs on urban roads. Moreover, studies considering traffic volume increase with a mixture of AVs and human-driven vehicles (HDVs) have rarely been conducted. Therefore, this study investigated the impact of gradual increments of AV penetration and traffic volume on urban roads. The study adopted a microsimulation approach using VISSIM with a Wiedmann 74 model for car-following behavior. Parameters for AVs were set at the SAE level 4 of automation. A real road network was chosen for the simulation having 13 intersections in a total distance of 4.5 km. The road network had various numbers of lanes from a single lane to five lanes in one direction. The network consists of a main arterial road and a parallel road serving nearby commercial and residential blocks. In total, 36 scenarios were investigated by a combination of AV penetrations and an increase in traffic volumes. The study found that, as AV penetration increased, traffic flow also improved, with a reduction of the average delay time of up to 31%. Also, as expected, links with three or four lanes had a more significant impact on the delay. In terms of road capacity increase, when the penetration of AVs was saturated at 100%, the road network could accommodate 40% more traffic.

SWIVEL JOINT WEAR-RESISTANCE INCREASE OF PROCESSING MACHINE MANIPULATORS

The work purpose: the choice of promising design-technological ways to support high indices of wear-resistance and friction costs decrease with regard to conditions of parts operation in swivels. The research methods: the set of tribotechnical researches on wear-resistance, on friction loss and physical and chemical parameters. The novelty: there are offered fundamentals for development of new designs of sliding bearings with increased wear-resistance at the expense of the favorable stressed state formation in functional layers, and also thermal physical and damping indices. Investigation results: support of increased thermal conductivity and thermal capacity increase of the materials under consideration gives possibility to increase considerably the friction unit efficiency in swivels, and also at the expense of thermal power accumulation with structural constituents of materials. Wear-resistance increase in the friction unit is provided with the formation of residual compression stresses in a functional surface layer, and the presence of an expanded spring in the bearing system contributes to the increase of its damping characteristics. Conclusions: the design and technological methods offered for working capacity increase and life increase of swivel parts allow assuring increased mechanical and tribological characteristics to a considerable extent and optimizing thermal modes.