COLAB:A Collaborative Multi-factor Scheduler for Asymmetric Multicore Processors

Funding: Partially funded by the UK EPSRC grants Discovery: Pattern Discovery and Program Shaping for Many-core Systems (EP/P020631/1) and ABC: Adaptive Brokerage for Cloud (EP/R010528/1); Royal Academy of Engineering under the Research Fellowship scheme.Increasingly prevalent asymmetric multicore processors (AMP) are necessary for delivering performance in the era of limited power budget and dark silicon. However, the software fails to use them efficiently. OS schedulers, in particular, handle asymmetry only under restricted scenarios. We have efficient symmetric schedulers, efficient asymmetric schedulers for single-threaded workloads, and efficient asymmetric schedulers for single program workloads. What we do not have is a scheduler that can handle all runtime factors affecting AMP for multi-threaded multi-programmed workloads. This paper introduces the first general purpose asymmetry-aware scheduler for multi-threaded multi-programmed workloads. It estimates the performance of each thread on each type of core and identifies communication patterns and bottleneck threads. The scheduler then makes coordinated core assignment and thread selection decisions that still provide each application its fair share of the processor's time. We evaluate our approach using the GEM5 simulator on four distinct big.LITTLE configurations and 26 mixed workloads composed of PARSEC and SPLASH2 benchmarks. Compared to the state-of-the art Linux CFS and AMP-aware schedulers, we demonstrate performance gains of up to 25% and 5% to 15% on average depending on the hardware setup.Postprin

Measurement of HQET Parameters and CKM Matrix Elements

The determination of CKM matrix elements in the b-sector is discussed, emphasizing the new measurements of Vub and Vcb by the CLEO collaboration.Comment: 4 pages, Latex, to be published in proceedings of Hadron 2001 at Protvin

Unitarity Constraints for Transverse Gauge Bosons at LEP and Supercolliders

Using asymptotic helicity amplitudes for Vector-Vector, Vector-Higgs and Higgs-Higgs scattering, we establish the unitarity constraints on the $SU(2)_c$ conserving and $W_\mu$ depending interactions, which at sufficiently high energies may create strong forces among the transverse vector boson and Higgs states. We then derive upper bounds for the couplings of these interactions, which depend on the high energy scale where unitarity is saturated. If \eg\, unitarity is saturated at 1TeV, then \lambda_W \lsim 0.12 is obtained. The implied relations between the present and future LEP results, and the possible observations of strong effects at supercolliders, are also discussedComment: 11 pages,postscript file of 1 figure appended at the end of the latex file (e-mail [email protected] PM/93-37 THES-TP 93/1

Building a Common Ground – The Use of Design Representation Cards for Enhancing Collaboration between Industrial Designers and Engineering Designers

To achieve success in today’s commercial environment, manufacturers have progressively adopted collaboration strategies. Industrial design has been increasingly used with engineering design to enhance competitiveness. Research between the two fields has been limited and existing collaboration methods have not achieved desired results. This PhD research project investigated the level of collaboration between industrial designers and engineering designers. The aim is to develop an integration tool for enhanced collaboration, where a common language would improve communication and create shared knowledge. An empirical research using questionnaires and observations identified 61 issues between industrial designers and engineering designers. The results were grouped and coded based on recurrence and importance, outlining 3 distinct problem categories in collaborative activity: conflicts in values and principles, differences in design representation, and education differences. A taxonomy further helped categorise design representations into sketches, drawings, models and prototypes. This knowledge was indexed into cards to provide uniform definition of design representations with key information. They should benefit practitioners and educators by serving as a decision-making guide and support a collaborative working environment. A pilot study first refined the layout and improved information access. The final validation involving interviews with practitioners revealed most respondents to be convinced that the tool would provide a common ground in design representations, contributing to enhanced collaboration. Additional interviews were sought from groups of final-year industrial design and engineering design students working together. Following their inter-disciplinary experience, nearly all respondents were certain that the cards would provide mutual understanding for greater product success. Lastly, a case study approach tested the cards in an industry-based project. A design diary captured and analysed the researchers’ activities and observations on a daily basis. It revealed positive feedback, reinforcing the benefits of the cards for successful collaboration in a multi-disciplinary environment. Keywords Industrial Design, Engineering Design, Collaboration, Design Representation, New Product Development.</p