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êł ì±ë„ 컎íší ìì€í ìì ëČì€íž ëČíŒë„Œ ìí I/O ë¶ëŠŹ êž°ëČì ì€ìŠì ê”Źí
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ŒëŹž(ììŹ)--ììžëíê” ëíì :êł”êłŒëí 컎íší°êł”íë¶,2019. 8. ìíì.To meet the exascale I/O requirements in the High-Performance Computing (HPC), a new I/O subsystem, named Burst Buffer, based on non-volatile memory, has been developed. However, the diverse HPC workloads and the bursty I/O pattern cause severe data fragmentation to SSDs, which creates the need for expensive garbage collection (GC) and also increase the number of bytes actually written to SSD. The new multi-stream feature in SSDs offers an option to reduce the cost of garbage collection. In this paper, we leverage this multi-stream feature to group the I/O streams based on the user IDs and implement this strategy in a burst buffer we call BIOS, short for Burst Buffer with an I/O Separation scheme. Furthermore, to optimize the I/O separation scheme in burst buffer environments, we propose a stream-aware scheduling policy based on burst buffer pools in workload manager and implement the real burst buffer system, BIOS framework, by integrating the BIOS with workload manager. We evaluate the BIOS and framework with a burst buffer I/O traces from Cori Supercomputer including a diverse set of applications. We also disclose and analyze the benefits and limitations of using I/O separation scheme in HPC systems. Experimental results show that the BIOS could improve the performance by 1.44Ă on average and reduce the Write Amplification Factor (WAF) by up to 1.20Ă, and prove that the framework can keep on the benefits of the I/O separation scheme in the HPC environment.Abstract
Introduction 1
Background and Challenges 5
Burst Buffer 5
Write Amplification in SSDs 6
Multi-streamed SSD 7
Challenges of Multi-stream Feature in Burst Buffers 7
I/O Separation Scheme in Burst Buffer 10
Stream Allocation Criteria 10
Implementation 12
Limitations of User ID-based Stream Allocation 14
BIOS Framework 15
Support in Workload Manager 15
Burst Buffer Pools 16
Stream-Aware Scheduling Policy 18
Workflow of BIOS Framework 20
Evaluation 21
Experiment Setup 21
Evaluation with Synthetic Workload 21
Evaluation with HPC Applications 25
Evaluation with Emulated Workload 27
Evaluation with Different Striping Configuration 29
Evaluation on BIOS Framework 30
Summary and Lessons Learned 33
An I/O Separation Scheme in Burst Buffer 33
Evaluation with Synthetic Workload 33
Evaluation with HPC Applications 33
Evaluation with Emulated Workload 34
Evaluation with Striping Configurations 34
A BIOS Framework 34
Evaluation with Real Burst Buffer Environments 34
Discussion 36
Limited Number of Nodes 36
Advanced BIOS Framework 37
Related work 38
Conclusions 40
Bibliography 42
ìŽëĄ 48Maste
Applications of satellite technology to broadband ISDN networks
Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization
A Quantitative Analysis and Guideline of Data Streaming Accelerator in Intel 4th Gen Xeon Scalable Processors
As semiconductor power density is no longer constant with the technology
process scaling down, modern CPUs are integrating capable data accelerators on
chip, aiming to improve performance and efficiency for a wide range of
applications and usages. One such accelerator is the Intel Data Streaming
Accelerator (DSA) introduced in Intel 4th Generation Xeon Scalable CPUs
(Sapphire Rapids). DSA targets data movement operations in memory that are
common sources of overhead in datacenter workloads and infrastructure. In
addition, it becomes much more versatile by supporting a wider range of
operations on streaming data, such as CRC32 calculations, delta record
creation/merging, and data integrity field (DIF) operations. This paper sets
out to introduce the latest features supported by DSA, deep-dive into its
versatility, and analyze its throughput benefits through a comprehensive
evaluation. Along with the analysis of its characteristics, and the rich
software ecosystem of DSA, we summarize several insights and guidelines for the
programmer to make the most out of DSA, and use an in-depth case study of DPDK
Vhost to demonstrate how these guidelines benefit a real application
GekkoFS: A temporary burst buffer file system for HPC applications
Many scientific fields increasingly use high-performance computing (HPC) to process and analyze massive amounts of experimental data while storage systems in todayâs HPC environments have to cope with new access patterns. These patterns include many metadata operations, small I/O requests, or randomized file I/O, while general-purpose parallel file systems have been optimized for sequential shared access to large files. Burst buffer file systems create a separate file system that applications can use to store temporary data. They aggregate node-local storage available within the compute nodes or use dedicated SSD clusters and offer a peak bandwidth higher than that of the backend parallel file system without interfering with it. However, burst buffer file systems typically offer many features that a scientific application, running in isolation for a limited amount of time, does not require. We present GekkoFS, a temporary, highly-scalable file system which has been specifically optimized for the aforementioned use cases. GekkoFS provides relaxed POSIX semantics which only offers features which are actually required by most (not all) applications. GekkoFS is, therefore, able to provide scalable I/O performance and reaches millions of metadata operations already for a small number of nodes, significantly outperforming the capabilities of common parallel file systems.Peer ReviewedPostprint (author's final draft
Concurrent cell rate simulation of ATM telecommunications network.
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Sustained release silk fibroin discs: Antibody and protein delivery for HIV prevention
With almost 2 million new HIV infections worldwide each year, the prevention of HIV infection is critical for stopping the pandemic. The only approved form of pre-exposure prophylaxis is a costly daily pill, and it is recognized that several options will be needed to provide protection to the various affected communities around the world. In particular, many at-risk people would benefit from a prevention method that is simple to use and does not require medical intervention or a strict daily regimen. We show that silk fibroin protein can be formulated into insertable discs that encapsulate either an antibody (IgG) or the potent HIV inhibitor 5P12-RANTES. Several formulations were studied, including silk layering, water vapor annealing and methanol treatment to stabilize the protein cargo and impact the release kinetics over weeks. In the case of IgG, high concentrations were released over a short time using methanol treatment, with more sustained results with the use of water vapor annealing and layering during device fabrication. For 5P12-RANTES, sustained release was obtained for 31âŻdays using water vapor annealing. Further, we show that the released inhibitor 5P12-RANTES was functional both in vitro and in ex vivo colorectal tissue. This work shows that silk fibroin discs can be developed into formidable tools to prevent HIV infection
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