Using Intelligent Prefetching to Reduce the Energy Consumption of a Large-scale Storage System

Many high performance large-scale storage systems will experience significant workload increases as their user base and content availability grow over time. The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) center hosts one such system that has recently undergone a period of rapid growth as its user population grew nearly 400% in just about three years. When administrators of these massive storage systems face the challenge of meeting the demands of an ever increasing number of requests, the easiest solution is to integrate more advanced hardware to existing systems. However, additional investment in hardware may significantly increase the system cost as well as daily power consumption. In this paper, we present evidence that well-selected software level optimization is capable of achieving comparable levels of performance without the cost and power consumption overhead caused by physically expanding the system. Specifically, we develop intelligent prefetching algorithms that are suitable for the unique workloads and user behaviors of the world\u27s largest satellite images distribution system managed by USGS EROS. Our experimental results, derived from real-world traces with over five million requests sent by users around the globe, show that the EROS hybrid storage system could maintain the same performance with over 30% of energy savings by utilizing our proposed prefetching algorithms, compared to the alternative solution of doubling the size of the current FTP server farm

Energy and Power Characterization of Parallel Programs Running on Intel Xeon Phi

Intel\u27s Xeon Phi coprocessor has successfully proved its capability by being used in Tianhe-2 and Stampede, two of the top ten most powerful supercomputers today. It is almost certain that the popularity of Xeon Phi in heterogeneous computing will grow significantly, which requires comprehensive studies on different aspects of this newly arrived many-core chip. Despite a number of previous studies on the performance of Xeon Phi, the power and energy behavior of the coprocessor has not been fully studied. In this paper, we present the performance, power and energy results of multiple parallel programs with contrasting workloads running on Intel Xeon Phi. Several interesting findings are derived from these results: 1) the Xeon Phi thread is power-hungry even when idle and altering the number of executing threads will largely affect the power consumption, 2) performance improvement and energy savings are highly related, 3) running code in native mode yields better performance and consumes less energy, and 4) co-running programs with complementary workloads has potential to conserve energy with negligible performance influence. In addition, we discuss an incorrect way of measuring power of Xeon Phi using the on-chip power sensors and present our solutions

Duodenal ischemia and upper GI bleeding are dose-limiting toxicities of 24-h continuous intra-arterial pancreatic perfusion of gemcitabine following vascular isolation of the pancreatic head: early results from the Regional Chemotherapy in Locally Advanced Pancreatic Cancer (RECLAP) study

BackgroundRegional chemotherapy is used successfully in the treatment of both primary and secondary malignancies, in particular of the peritoneal surface and the liver, and is currently explored as an attractive approach for patients with locally advanced pancreatic ductal adenocarcinoma. To establish the feasibility and toxicity of regional intra-arterial gemcitabine delivered as a 24-h continuous infusion to the pancreas as a novel treatment option for patients with locally advanced PDAC a phase I clinical trial was conducted.MethodsBetween April 2011 and September 2013 six patients with biopsy confirmed, borderline or unresectable pancreatic adenocarcinoma, and having received at least one line of systemic chemotherapy, underwent vascular redistribution of the inflow to the head of the pancreas by arterial coil embolization followed by perfusion catheter placement within the splenic artery. Patients were treated with increasing doses of gemcitabine administered by continuous splenic arterial infusion over 24 h with inter-patient and intra-patient dose escalation scheme. The primary endpoint was toxicity of the intra-arterial gemcitabine regimen and to establish the maximum tolerated dose.ResultsCatheter placement and gemcitabine infusion was successful in all patients enrolled to date (n = 6). Four out of six patients experienced catheter tip migration requiring replacement or revision. Patients received a median of four doses of 24-h gemcitabine infusion. Two patients developed grade 3 and 4 duodenal ischemia and upper gastrointestinal bleeding. Median overall survival was 15.3 months and median time to progression was 3 months. Three patients (50 %, n = 3/6) progressed systemically. Two patients had stable disease >4 months following treatment and underwent pancreaticoduodenectomy.ConclusionsWhile technically feasible to treat locally advanced pancreatic ductal adenocarcinoma, prolonged regional pancreatic perfusion with gemcitabine following pancreatic arterial redistribution carries a high risk for gastrointestinal toxicity. Shorter infusion schedules with frequent on treatment evaluations should be considered for future clinical trials