Software

About: Software is a research topic. Over the lifetime, 130577 publications have been published within this topic receiving 2028987 citations. The topic is also known as: computer software & computational tool.

hwloc: A Generic Framework for Managing Hardware Affinities in HPC Applications

Abstract: The increasing numbers of cores, shared caches and memory nodes within machines introduces a complex hardware topology. High-performance computing applications now have to carefully adapt their placement and behavior according to the underlying hierarchy of hardware resources and their software affinities. We introduce the Hardware Locality (hwloc) software which gathers hardware information about processors, caches, memory nodes and more, and exposes it to applications and runtime systems in a abstracted and portable hierarchical manner. hwloc may significantly help performance by having runtime systems place their tasks or adapt their communication strategies depending on hardware affinities. We show that hwloc can already be used by popular high-performance OpenMP or MPI software. Indeed, scheduling OpenMP threads according to their affinities or placing MPI processes according to their communication patterns shows interesting performance improvement thanks to hwloc. An optimized MPI communication strategy may also be dynamically chosen according to the location of the communicating processes in the machine and its hardware characteristics.

Network effects, software provision, and standardization*

Abstract: In this paper we examine the software provision decision of software firms. The provision decision by software firms determines the value and hence the market share of competing hardware technologies. We show how the provision decision by software firms determines whether multiple hardware technologies are supported in equilibrium or whether there is de facto standardization, with only one hardware technology supplied with software in equilibrium. We show that when consumers place a high value on software variety, there is a suboptimal amount of standardization by the market.

The Method of Layers

Abstract: Distributed applications are being developed that contain one or more layers of software servers. Software processes within such systems suffer contention delays both for shared hardware and at the software servers. The responsiveness of these systems is affected by the software design, the threading level and number of instances of software processes, and the allocation of processes to processors. The Method of Layers (MOL) is proposed to provide performance estimates for such systems. The MOL uses the mean value analysis (MVA) linearizer algorithm as a subprogram to assist in predicting model performance measures. >

Models and languages for parallel computation

Abstract: We survey parallel programming models and languages using six criteria to assess their suitability for realistic portable parallel programming. We argue that an ideal model should by easy to program, should have a software development methodology, should be architecture-independent, should be easy to understand, should guarantee performance, and should provide accurate information about the cost of programs. These criteria reflect our belief that developments in parallelism must be driven by a parallel software industry based on portability and efficiency. We consider programming models in six categories, depending on the level of abstraction they provide. Those that are very abstract conceal even the presence of parallelism at the software level. Such models make software easy to build and port, but efficient and predictable performance is usually hard to achieve. At the other end of the spectrum, low-level models make all of the messy issues of parallel programming explicit (how many threads, how to place them, how to express communication, and how to schedule communication), so that software is hard to build and not very portable, but is usually efficient. Most recent models are near the center of this spectrum, exploring the best tradeoffs between expressiveness and performance. A few models have achieved both abstractness and efficiency. Both kinds of models raise the possibility of parallelism as part of the mainstream of computing.

Policies for secure software execution

Abstract: A system and method that automatically, transparently and securely controls software execution by identifying and classifying software, and locating a rule and associated security level for executing executable software. The security level may disallow the software's execution, restrict the execution to some extent, or allow unrestricted execution. To restrict software, a restricted access token may be computed that reduces software's access to resources, and/or removes privileges, relative to a user's normal access token. The rules that control execution for a given machine or user may be maintained in a restriction policy, e.g., locally maintained and/or in a group policy object distributable over a network. Software may be identified/classified by a hash of its content, by a digital signature, by its file system or network path, and/or by its URL zone. For software having multiple classifications, a precedence mechanism is provided to establish the applicable rule/security level.