Cicada: Predictive Guarantees for Cloud Network Bandwidth

In cloud-computing systems, network-bandwidth guarantees have been shown to improve predictability of application performance and cost. Most previous work on cloud-bandwidth guarantees has assumed that cloud tenants know what bandwidth guarantees they want. However, application bandwidth demands can be complex and time-varying, and many tenants might lack sufficient information to request a bandwidth guarantee that is well-matched to their needs. A tenant's lack of accurate knowledge about its future bandwidth demands can lead to over-provisioning (and thus reduced cost-efficiency) or under-provisioning (and thus poor user experience in latency-sensitive user-facing applications). We analyze traffic traces gathered over six months from an HP Cloud Services datacenter, finding that application bandwidth consumption is both time-varying and spatially inhomogeneous. This variability makes it hard to predict requirements. To solve this problem, we develop a prediction algorithm usable by a cloud provider to suggest an appropriate bandwidth guarantee to a tenant. The key idea in the prediction algorithm is to treat a set of previously observed traffic matrices as "experts" and learn online the best weighted linear combination of these experts to make its prediction. With tenant VM placement using these predictive guarantees, we find that the inter-rack network utilization in certain datacenter topologies can be more than doubled

I/O Is Faster Than the CPU - Let's Partition Resources and Eliminate (Most) OS Abstractions

Peer reviewe

Discovery of platelet-type 12-human lipoxygenase selective inhibitors by high-throughput screening of structurally diverse libraries.

Human lipoxygenases (hLO) have been implicated in a variety of diseases and cancers and each hLO isozyme appears to have distinct roles in cellular biology. This fact emphasizes the need for discovering selective hLO inhibitors for both understanding the role of specific lipoxygenases in the cell and developing pharmaceutical therapeutics. To this end, we have modified a known lipoxygenase assay for high-throughput (HTP) screening of both the National Cancer Institute (NCI) and the UC Santa Cruz marine extract library (UCSC-MEL) in search of platelet-type 12-hLO (12-hLO) selective inhibitors. The HTP screen led to the characterization of five novel 12-hLO inhibitors from the NCI repository. One is the potent but non-selective michellamine B, a natural product, anti-viral agent. The other four compounds were selective inhibitors against 12-hLO, with three being synthetic compounds and one being alpha-mangostin, a natural product, caspase-3 pathway inhibitor. In addition, a selective inhibitor was isolated from the UCSC-MEL (neodysidenin), which has a unique chemical scaffold for a hLO inhibitor. Due to the unique structure of neodysidenin, steady-state inhibition kinetics were performed and its mode of inhibition against 12-hLO was determined to be competitive (K(i)=17microM) and selective over reticulocyte 15-hLO-1 (K(i) 15-hLO-1/12-hLO\u3e30)

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in 1982. Our focus is information technology that is relevant to the technical strategy of the Corporation, and that has the potential to open new business opportunities. Research at WRL includes Internet protocol design and implementation, tools for binary optimization, hardware and software mechanisms to support scalable shared memory, graphics VLSI ICs, hand-held computing, and more. Our tradition at WRL is to test our ideas by extensive software or hardware prototyping. We publish the results of our work in a variety of journals, conferences, research reports, and technical notes. This document is a research report. Research reports are normally accounts of completed research and may include material from earlier technical notes. We use technical notes for rapid distribution of technical material; usually this represents research in progress. You can retrieve research reports and technical notes via the World Wide Web at

A Better Update Policy

while a modification that fills a block results in an immediate, although asynchronous, write. The Some file systems can delay writing modified ULTRIX operating system can be configured to be data to disk, in order to reduce disk traffic and overeven more aggressive, delaying all writes of modified head. Prudence dictates that such delays be bounded, data. in case the system crashes. We refer to an algorithm used to decide when to write delayed data back to Without some bound on the age of a delayeddisk as an update policy. Traditional UNIX systems write block, a system crash could cause loss of aruse a periodic update policy, writing back all bitrary data. Users would not tolerate this, so the file delayed-write data once every 30 seconds. Periodic system does push delayed-write data out to disk, after update is easy to implement but performs quite badly a while. We use the term update policy to describe in some cases. This paper describes an approximate the algorithm that decides what to write out, and implementation of an interval periodic update policy, when