1,720,953 research outputs found
SSD-Based Workload Characteristics and Their Performance Implications
No full textThis repo contains blocktrace from YCSB benchmark run on a RocksDB KV store hosted on a ext4 File System.
More details can be found in the README file and also in our ACM TOS Paper here: https://dl.acm.org/doi/10.1145/3423137
Please cite our paper, if the trace is useful in your research:
@article{10.1145/3423137,
author = {Yadgar, Gala and Gabel, Moshe and Jaffer, Shehbaz and Schroeder, Bianca},
title = {SSD-Based Workload Characteristics and Their Performance Implications},
year = {2021},
issue_date = {January 2021},
publisher = {Association for Computing Machinery}, address = {New York, NY, USA},
volume = {17},
number = {1},
issn = {1553-3077},
url = {https://doi.org/10.1145/3423137},
doi = {10.1145/3423137},
abstract = {Storage systems are designed and optimized relying on wisdom derived from analysis studies of file-system and block-level workloads. However, while SSDs are becoming a dominant building block in many storage systems, their design continues to build on knowledge derived from analysis targeted at hard disk optimization. Though still valuable, it does not cover important aspects relevant for SSD performance. In a sense, we are “searching under the streetlight,” possibly missing important opportunities for optimizing storage system design.We present the first I/O workload analysis designed with SSDs in mind. We characterize traces from four repositories and examine their “temperature” ranges, sensitivity to page size, and “logical locality.” We then take the first step towards correlating these characteristics with three standard performance metrics: write amplification, read amplification, and flash read costs. Our results show that SSD-specific characteristics strongly affect performance, often in surprising ways.}, journal = {ACM Trans. Storage}, month = jan, articleno = {8}, numpages = {26}, keywords = {locality, workload characterization, I/O workload analysis, SSD}
}Paper BibTex:
@article{10.1145/3423137,
author = {Yadgar, Gala and Gabel, MOSHE and Jaffer, Shehbaz and Schroeder, Bianca},
title = {SSD-Based Workload Characteristics and Their Performance Implications},
year = {2021},
issue_date = {January 2021},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {17},
number = {1},
issn = {1553-3077},
url = {https://doi.org/10.1145/3423137},
doi = {10.1145/3423137},
abstract = {Storage systems are designed and optimized relying on wisdom derived from analysis studies of file-system and block-level workloads. However, while SSDs are becoming a dominant building block in many storage systems, their design continues to build on knowledge derived from analysis targeted at hard disk optimization. Though still valuable, it does not cover important aspects relevant for SSD performance. In a sense, we are "searching under the streetlight," possibly missing important opportunities for optimizing storage system design.We present the first I/O workload analysis designed with SSDs in mind. We characterize traces from four repositories and examine their "temperature" ranges, sensitivity to page size, and "logical locality." We then take the first step towards correlating these characteristics with three standard performance metrics: write amplification, read amplification, and flash read costs. Our results show that SSD-specific characteristics strongly affect performance, often in surprising ways.},
journal = {ACM Trans. Storage},
month = jan,
articleno = {8},
numpages = {26},
keywords = {locality, workload characterization, I/O workload analysis, SSD}
Improving Reliability and Performance of Storage Stacks on next generation Solid State Drives
Get PDFSolid State Drives (SSDs) are increasingly replacing HDDs as the primary source of persistent storage medium in both data centers and personal storage devices. SSDs offer higher performance and consume less power. They also bring two challenges in the storage space:
First, SSDs have different reliability characteristics than HDDs. However, the impact of various SSD-based errors on the overlying software stack is not well known. Furthermore, as the demand for high-capacity SSDs increases, more bits are stored within the same voltage range of the underlying SSD medium.
Second, with the end of Moore’s law, there is increased emphasis on disaggregated computing where data-intensive computation takes place on a processor within the device. Applications can offload computation from the host to the device, save host CPU cycles, lower host-to-device latency, and reduce bandwidth utilization. However, such devices are expensive, hard to program, and may not be suitable for all application computation offloads.
We address these reliability and performance challenges for SSDs as follows:
First, we evaluate file system reliability in the presence of SSD errors. We notice that real-world file systems often make performance assumptions for SSDs that impact their reliability. We find that real-world file systems incur severe failures, such as unmountable drives in 16% of our extensive test suite emulating 7000 SSD-based errors.
Second, we invent a novel voltage-based Write Once Memory (WOM-v) coding scheme that reduces the number of erase operations that take place on every overwrite to the SSD. We show that for QLC SSD, the number of erase operations can be reduced from 4.4x to 11.1x for real-world workloads.
Third, we build Nescafe, a computational storage framework to evaluate performance gains of offloading computational tasks to an emulated near storage device. We show that real-world, compute-intensive applications like zlib compression, jbd2 checksum computation, and LSM Tree compaction are easy to offload to a computational device using our framework. We show that Nescafe is generic and simple to extend to different types of block, stream, and application-based workloads.Ph.D
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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