Mothy's talk is happening now! On Sun, Apr 8, 2018 at 5:03 PM, Tom Anderson <t...@cs.washington.edu> wrote:
> Revised, now with Ihsan's schedule and abstract. > > ---- > With NSDI being local, we have a number of talks queued up this week, and > most of the visitors will have time after/before to meet with us. Please > sign up! Note that several of the talks have non-standard start times. > Abstracts collected below. > > Wednesday, CSE 305, 1:30pm > Vijay Chidambaram, UT Austin > PebblesDB: Building Key-Value Stores Using Fragmented Log-Structured Merge > Trees > > https://reserve.cs.washington.edu/visitor/week.php?year=2018 > &month=04&day=11&room=3050&area=5 > > Thursday, CSE 305, 11am > Mothy Roscoe, ETH Zurich > Enzian: Research Computer > > https://reserve.cs.washington.edu/visitor/week.php?year=2018 > &month=4&day=8&area=5&room=3080 > > Thursday, CSE 305, 12pm > Ihsan Qazi, LUMS > Understanding Internet Access in the Developing World > > https://reserve.cs.washington.edu/visitor/week.php?year=2018 > &month=04&day=12&area=5&room=3113 > > > Friday, CSE 305, 12:00pm > Keith Winstein, Stanford > Tiny Functions for Codecs, Compilation, and (maybe) Everything > > https://reserve.cs.washington.edu/visitor/week.php?year=2018 > &month=4&day=8&area=5&room=3103 > ---- > PebblesDB: Building Key-Value Stores Using Fragmented Log-Structured Merge > Trees > > Key-value stores such as LevelDB and RocksDB have become a fundamental > part of the systems infrastructure. However, these stores suffer from high > write amplification: for example, 45 GB of data written to RocksDB results > in 1.8 TB (28x) written to storage. In this talk, I show that the write > amplification problem is fundamental to the Log-Structured Merge Trees data > structure that underlies these stores. I present a novel data structure > that is inspired by Skip Lists, termed Fragmented Log-Structured Merge > Trees (FLSM). FLSM introduces the notion of guards to organize logs, and > avoids rewriting data in the same level. I will describe PebblesDB, a new > key-value store that we built by modifying HyperLevelDB to use the FLSM > data structure. I will briefly present our evaluation which shows that > PebblesDB increases write throughput by 6.7x (compared to RocksDB and > LevelDB) while simultaneously reducing write amplification by 2.4-3x. > PebblesDB is open-source (https://github.com/utsaslab/pebblesdb), and I > hope to convince some of you to incorporate it into new systems you build :) > > > Enzian: Research Computer > > Academic research in rack-scale and datacenter computing > today is hamstrung by lack of hardware. Cloud providers and hardware > vendors build custom accelerators, interconnects, and networks for > commercially important workloads, but university researchers are stuck > with commodity, off-the-shelf parts. > > Enzian is a research computer developed at ETH Zurich in collaboration > with Cavium and Xilinx which addresses this problem. An Enzian board > consists of a server-class ARMv8 SoC tightly coupled and coherent with > a large FPGA (eliminating PCIe), with about 0.5 TB DDR4 and about 600 > Gb/s of network I/O either to the CPU (over Ethernet) or directly to > the FPGA (potentially over custom protocols). Enzian runs both > Barrelfish and Linux operating systems. > > Many Enzian boards can be connected in a rack-scale machine (either > with or without a discrete switch), and the design is intended to > allow many different research use-cases: zero-overhead run-time > verification of software invariants, novel interconnect protocols for > remote memory access, hardware enforcement of access control in a > large machine, high-performance streaming analytics using a > combination of software and configurable hardware, and much more. > By providing a powerful and flexible platform for computer systems > research, Enzian aims to enable more relevant and far-reaching work on > future compute platforms. > > Understanding Internet Access in the Developing World > > In this talk, I will present my recent research on Internet access in > developing countries. In the first half of my talk, I will present a study > on the characteristics of mobile devices in developing regions. Using a > dataset of 0.5 million subscribers from one of the largest cellular > operators in Pakistan, I will present an analysis of cell phones being used > based on different features (e.g., CPU, memory, and cellular interface). > Our analysis reveals potential device-level bottlenecks for Internet > access, which can inform infrastructure design for improving mobile web > performance. (This work appeared in ACM IMC 2016) Another accessibility > challenge in developing countries is the rise in Internet censorship > events, which can have a substantial impact on various stakeholders in the > Internet ecosystem (e.g., users, content providers, ISPs, and advertisers). > In the second half of my talk, I will discuss how Internet censorship poses > an economic threat to online advertising, which plays an essential role in > enabling the free Web by allowing publishers to monetize their services. > Then I will describe a system we designed that enables relevant ads while > retaining the effectiveness of censorship resistance tools (e.g., Tor). > (This work appeared in ACM HotNets 2017) > > Tiny Functions for Codes, Compilation, and (maybe) Soon Everything > > Networks, applications, and media codecs frequently treat one another as > strangers. By expressing large systems as compositions of small, pure > functions, we've found it's possible to achieve tighter couplings between > these components, improving performance without giving up modularity or the > ability to debug. I'll discuss our experience with systems that demonstrate > this basic idea: ExCamera (NSDI 2017) parallelizes video encoding into > thousands of tiny tasks, each handling a fraction of a second of video, > much shorter than the interval between key frames, and executing in > parallel on AWS Lambda. This was the first system to demonstrate > "burst-parallel" thousands-way computation on functions-as-a-service > infrastructure. Salsify (NSDI 2018) is a low-latency network video system > that uses a purely functional video codec to explore execution paths of the > encoder without committing to them, allowing it to closely match the > capacity estimates from a video-aware transport protocol. This architecture > outperforms more loosely-coupled applications -- Skype, Facetime, Hangouts, > WebRTC -- in delay and visual quality, and suggests that while improvements > in video codecs may have reached the point of diminishing returns, video > systems still have low-hanging fruit. Lepton (NSDI 2017) uses a purely > functional JPEG/VP8 transcoder to compress images in parallel across a > distributed network filesystem with arbitrary block boundaries. This > free-software system is in production at Dropbox and has compressed, by > 23%, more than 200 petabytes of user JPEGs. > > Based on our experience, we propose an intermediate representation for > interactive lambda computing, called cloud "thunks" -- stateless closures > that describe their data-dependencies by content-hash, separating the > specification of an algorithm from its schedule and execution. We have > created a tool that extracts this IR from off-the-shelf software build > systems, letting the user treat a FaaS service like a 5,000-core build farm > with global memoization of results. Expressing systems and protocols as > compositions of small, pure functions has the potential to lead to a wave > of "general-purpose" lambda computing, permitting us to transform everyday > time-consuming operations into large numbers of functions executing with > massive parallelism for short durations in the cloud. > > > _______________________________________________ > Uw-systems mailing list > uw-syst...@cs.washington.edu > https://mailman.cs.washington.edu/mailman/listinfo/uw-systems > >
_______________________________________________ change mailing list change@change.washington.edu http://changemm.cs.washington.edu/mailman/listinfo/change
