Users of cloud services are presented with a bewildering choice of VM types and the choice of VM can have significant implications on performance and cost. In this paper we address the fundamental problem of accurately and economically choosing the best VM for a given workload and user goals. To address the problem of optimal VM selection, we present PARIS, a data-driven system that uses a novel hybrid offline and online data collection and modeling framework to provide accurate performance estimates with minimal data collection. PARIS is able to predict workload performance for different user-specified metrics, and resulting costs for a wide range of VM types and workloads across multiple cloud providers. When compared to sophisticated baselines, including collaborative filtering and a linear interpolation model using measured workload performance on two VM types, PARIS produces significantly better estimates of performance. For instance, it reduces runtime prediction error by a factor of 4 for some workloads on both AWS and Azure. The increased accuracy translates into a 45% reduction in user cost while maintaining performance.

Summary form only given, as follows. Parallel computing has become ubiquitous and relates to challenging computational problems in science via business-driven computing to mobile computing. The scope has widened dramatically over the last decade. This panel will debate and speculate on how the parallel computing landscape is expected to change in the years to come. Areas of focus will include: (1) Computing platforms: How will we be able to maintain the performance growth of the past and what will be the major challenges in the next 10 years and beyond that? What technical barriers are anticipated and what disruptive technologies are behind the corner? (2) Software: How will software infrastructures evolve to meet performance requirements in the next 10 years and beyond? How will we ever be able to hide parallelism obstacles for the masses and what is the road forward towards that? (3) Algorithms: What will be the major computational problems to tackle in the next 10 years and beyond? What are the most challenging algorithmic problems to solve? (4) Applications: What will be the next wave of grand challenge problems to focus on in the next 10 years and beyond? What will be the major performance driving applications in the general and mobile computing domains? A record of the panel discussion was not made available for publication as part of the conference proceedings.

Resource management is the dynamic allocation and de-allocation by an operating system of processor cores, memory pages, and various types of bandwidth to computations that compete for those resources. The objective is to allocate resources so as to optimize responsiveness subject to the finite resources available. Historically, resource management solutions have been relatively unsystematic, and now the very assumptions underlying the traditional strategies fail to hold. First, applications increasingly differ in their ability to exploit resources, especially processor cores. Second, application responsiveness is approximately two-valued for "Quality-Of-Service" (QOS) applications, depending on whether deadlines are met. Third, power and battery energy have become constrained. This talk will propose a scheme for addressing the operating system resource management problem.

We present novel algorithms for computing discrete Fourier transforms with high performance on GPUs. We present hierarchical, mixed radix FFT algorithms for both power-of-two and non-power-of-two sizes. Our hierarchical FFT algorithms efficiently exploit shared memory on GPUs using a Stockham formulation. We reduce the memory transpose overheads in hierarchical algorithms by combining the transposes into a block-based multi-FFT algorithm. For non-power-of-two sizes, we use a combination of mixed radix FFTs of small primes and Bluestein's algorithm. We use modular arithmetic in Bluestein's algorithm to improve the accuracy. We implemented our algorithms using the NVIDIA CUDA API and compared their performance with NVIDIA's CUFFT library and an optimized CPU-implementation (Intel's MKL) on a high-end quad-core CPU. On an NVIDIA GPU, we obtained performance of up to 300 GFlops, with typical performance improvements of 2–4× over CUFFT and 8–40× improvement over MKL for large sizes.

Gather and scatter are two fundamental data-parallel operations, where a large number of data items are read (gathered) from or are written (scattered) to given locations. In this paper, we study these two operations on graphics processing units (GPUs).