scholarly journals TA-CLOCK: Tendency-Aware Page Replacement Policy for Hybrid Main Memory in High-Performance Embedded Systems

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1111
Author(s):  
Jun Hyeong Choi ◽  
Kyung Min Kim ◽  
Jong Wook Kwak

Recently, high-performance embedded systems have adopted phase change memory (PCM) as their main memory because PCMs have attractive advantages, such as non-volatility, byte-addressability, high density, and low power consumption. However, PCMs have disadvantages, such as limited write endurance in each cell and high write latency compared to DRAMs. Therefore, researchers have investigated methods for enhancing the limitations of PCMs. In this paper, we propose a page replacement policy called tendency-aware CLOCK (TA-CLOCK) for the hybrid main memory of embedded systems. To improve the limited write endurance of PCMs, TA-CLOCK classifies the page access tendency of the victim page through access pattern analysis and determines the migration location of the victim page. Through the classification of the page access tendency, TA-CLOCK reduces unnecessary page migrations from DRAMs to PCMs. Unnecessary migrations cause an increase in write operations in PCMs and the energy consumption of the hybrid main memory in embedded systems. Thus, our proposed policy improves the limited write endurance of PCMs and enhances the access latency of the hybrid main memory of embedded systems by classifying the page access tendency. We compared the TA-CLOCK with existing page replacement policies to evaluate its performance. In our experiments, TA-CLOCK reduced the number of write operations in PCMs by 71.5% on average, and it enhanced the energy delay product by 38.3% on average compared with other page replacement policies.

2009 ◽  
Vol 37 (3) ◽  
pp. 24-33 ◽  
Author(s):  
Moinuddin K. Qureshi ◽  
Vijayalakshmi Srinivasan ◽  
Jude A. Rivers

2020 ◽  
Vol 108 ◽  
pp. 560-573
Author(s):  
Ji-Tae Yun ◽  
Su-Kyung Yoon ◽  
Jeong-Geun Kim ◽  
Shin-Dug Kim

Author(s):  
A. Ferrerón Labari ◽  
D. Suárez Gracia ◽  
V. Viñals Yúfera

In the last years, embedded systems have evolved so that they offer capabilities we could only find before in high performance systems. Portable devices already have multiprocessors on-chip (such as PowerPC 476FP or ARM Cortex A9 MP), usually multi-threaded, and a powerful multi-level cache memory hierarchy on-chip. As most of these systems are battery-powered, the power consumption becomes a critical issue. Achieving high performance and low power consumption is a high complexity challenge where some proposals have been already made. Suarez et al. proposed a new cache hierarchy on-chip, the LP-NUCA (Low Power NUCA), which is able to reduce the access latency taking advantage of NUCA (Non-Uniform Cache Architectures) properties. The key points are decoupling the functionality, and utilizing three specialized networks on-chip. This structure has been proved to be efficient for data hierarchies, achieving a good performance and reducing the energy consumption. On the other hand, instruction caches have different requirements and characteristics than data caches, contradicting the low-power embedded systems requirements, especially in SMT (simultaneous multi-threading) environments. We want to study the benefits of utilizing small tiled caches for the instruction hierarchy, so we propose a new design, ID-LP-NUCAs. Thus, we need to re-evaluate completely our previous design in terms of structure design, interconnection networks (including topologies, flow control and routing), content management (with special interest in hardware/software content allocation policies), and structure sharing. In CMP environments (chip multiprocessors) with parallel workloads, coherence plays an important role, and must be taken into consideration.


Author(s):  
A.A. Filimonova ◽  
◽  
N.D. Chichirova ◽  
A.A. Chichirov ◽  
A.A. Batalova ◽  
...  

The article provides an overview of modern high-performance combined-cycle plants and gas turbine plants with waste heat boilers. The forecast for the introduction of gas turbine equipment at TPPs in the world and in Russia is presented. The classification of gas turbines according to the degree of energy efficiency and operational characteristics is given. Waste heat boilers are characterized in terms of design and associated performance and efficiency. To achieve high operating parameters of gas turbine and boiler equipment, it is necessary to use, among other things, modern water treatment equipment. The article discusses modern effective technologies, the leading place among which is occupied by membrane, and especially baromembrane methods of preparing feed water-waste heat boilers. At the same time, the ion exchange technology remains one of the most demanded at TPPs in the Russian Federation.


2020 ◽  
Vol 13 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Dhanapal Angamuthu ◽  
Nithyanandam Pandian

<P>Background: The cloud computing is the modern trend in high-performance computing. Cloud computing becomes very popular due to its characteristic of available anywhere, elasticity, ease of use, cost-effectiveness, etc. Though the cloud grants various benefits, it has associated issues and challenges to prevent the organizations to adopt the cloud. </P><P> Objective: The objective of this paper is to cover the several perspectives of Cloud Computing. This includes a basic definition of cloud, classification of the cloud based on Delivery and Deployment Model. The broad classification of the issues and challenges faced by the organization to adopt the cloud computing model are explored. Examples for the broad classification are Data Related issues in the cloud, Service availability related issues in cloud, etc. The detailed sub-classifications of each of the issues and challenges discussed. The example sub-classification of the Data Related issues in cloud shall be further classified into Data Security issues, Data Integrity issue, Data location issue, Multitenancy issues, etc. This paper also covers the typical problem of vendor lock-in issue. This article analyzed and described the various possible unique insider attacks in the cloud environment. </P><P> Results: The guideline and recommendations for the different issues and challenges are discussed. The most importantly the potential research areas in the cloud domain are explored. </P><P> Conclusion: This paper discussed the details on cloud computing, classifications and the several issues and challenges faced in adopting the cloud. The guideline and recommendations for issues and challenges are covered. The potential research areas in the cloud domain are captured. This helps the researchers, academicians and industries to focus and address the current challenges faced by the customers.</P>


Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 937-945
Author(s):  
Ruihuan Zhang ◽  
Yu He ◽  
Yong Zhang ◽  
Shaohua An ◽  
Qingming Zhu ◽  
...  

AbstractUltracompact and low-power-consumption optical switches are desired for high-performance telecommunication networks and data centers. Here, we demonstrate an on-chip power-efficient 2 × 2 thermo-optic switch unit by using a suspended photonic crystal nanobeam structure. A submilliwatt switching power of 0.15 mW is obtained with a tuning efficiency of 7.71 nm/mW in a compact footprint of 60 μm × 16 μm. The bandwidth of the switch is properly designed for a four-level pulse amplitude modulation signal with a 124 Gb/s raw data rate. To the best of our knowledge, the proposed switch is the most power-efficient resonator-based thermo-optic switch unit with the highest tuning efficiency and data ever reported.


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