Using Latency to Evaluate Computer System Performance

Building high performance computer systems requires an understanding of the behaviour of systems and what makes them fast or slow. In addition to our file system performance analysis, we have a number of projects in measuring, evaluating, and understanding system performances. The conventional methodology for system performance measurement, which relies primarily on throughput-sensitive benchmarks and throughput metrics, has major limitations when analyzing the behaviour and performance of interactive workloads. The increasingly interactive character of personal computing demands new ways of measuring and analyzing system performance. In this paper, we present a combination of measurement techniques and benchmark methodologies that address these problems. We use some simple methods for making direct and precise measurements of event handling latency in the context of a realistic interactive application. We analyze how results from such measurements can be used to understand the detailed behaviour of latency-critical events. We demonstrate our techniques in an analysis of the performance of two releases of Windows 9x and Windows XP Professional. Our experience indicates that latency can be measured for a class of interactive workloads, providing a substantial improvement in the accuracy and detail of performance information over measurements based strictly on throughput

Comparative Study on the Epidermal Features of Twelve Under-Utilized Legume Accessions

Seeds of six species of twelve accessions of miscellaneous legumes were obtained from the germplasm unit of the International Institute of Tropical Agriculture (IITA), Ibadan, Oyo State, Nigeria. The seeds were planted into plots of 5m long, spaced 1 meter apart at the botanical garden of the University of Agriculture, Abeokuta (UNAAB), Ogun State, Nigeria. Leaves of the plants were assessed for their genetic and phylogenetic relatedness through diagnostic epidermal studying of the cell shapes, anticlinal wall types and stomatal characteristics at the abaxial and adaxial surfaces. The cell shapes, anticlinal wall types and the stomatal characteristics revealed some correlations among the studied taxa. All the species were amphiostomatic possessing stomata on both the abaxial and adaxial surfaces. Proportions of the stomata distributions among the taxa were 75% (paracytic), 16.67% (anomocytic) and 8.3% (anisocytic) at both surfaces. There was no accession with diacytic stoma. Cell shapes were 75% polygonal, 25% irregular at the abaxial surfaces and 66.67%, 33.33% irregular and polygonal respectively at the adaxial surface. The prevalent anticlinal wall type was curved (41.67%) followed by curved/slightly straight (33.3%) and slightly straight (25%) at both surfaces. Result of the epidermal features of the studied taxa revealed some diagnostic characteristics that could be used for taxonomic decisio