Matt Johnson

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Energy and power consumption are becoming critical metrics in the design and usage of high performance systems. We have extended the Performance API (PAPI) analysis library to measure and report energy and power values. These values are reported using the existing PAPI API, allowing code previously instrumented for performance counters to also measure power(More)
The PAPI library [1] was originally developed to provide portable access to the hardware performance counters found on a diverse collection of modern microprocessors. Rather than learning and writing to a new performance infrastructure each time code is moved to a new machine, measurement code can be written to the PAPI API which abstracts away the(More)
This paper describes extensions to the PAPI hardware counter library for virtual environments, called PAPI-V. The extensions support timing routines, I/O measurements, and processor counters. The PAPI-V extensions will allow application and tool developers to use a familiar interface to obtain relevant hardware performance monitoring information in virtual(More)
BACKGROUND In the past few years there has been a political imperative driving the creation of European Reference Networks as these are considered a promising way to achieve equity in access to the most up to date medical care across Europe. The right to equity in the access to care was established by the directive of the European Parliament and of the(More)
Nearly 240 years after Joseph Priestley’s influential experiments involving a mouse, a plant and a bell jar the need and desire to study photosynthesis and the environment has not diminished. In fact, it is well recognized that the relationship between photosynthesis and the environment is key to understanding the health of our planet, in addition to(More)
Cloud computing has been increasingly adopted by users and providers to promote a flexible, scalable and tailored access to computing resources. Nonetheless, the consolidation of this paradigm has uncovered some of its limitations. Initially devised by corporations with direct control over large amounts of computational resources, cloud computing is now(More)
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