Compressed Swapping for NAND Flash Memory Based Embedded Systems

Park, Sangduck; Lim, Hong En; Chang, Hoseok; Sung, Wonyong

doi:10.1007/11512622_34

Cited by 4 publications

(4 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A selective compression scheme that only stores data with a low compression ratio to remove unnecessary decompression delay and data bloat from having metadata was also proposed for managing compressed entries [36], [37]. The existing selective compression schemes, unlike the one proposed in this paper, compress the incoming data to determine their compression ratio.…”

Section: B Swap Schemes For Mobile Devicesmentioning

confidence: 99%

$ezswap$ : Enhanced Compressed Swap Scheme for Mobile Devices

Kim

Seo

2019

IEEE Access

View full text Add to dashboard Cite

The limited memory capacity of mobile devices leads to the popular use of compressed swap schemes, which reduce the I/O operations involving the swapping in and out of infrequently accessed pages. However, most of the current compressed swap schemes indiscriminately compress and store all swap-out pages. Considering that both energy and computing power are scarce resources in mobile devices, and modern applications frequently deal with already-compressed multimedia data, this blind approach may cause adverse impacts. In addition, they focus only on anonymous pages and not on file-mapped pages, because the latter are backed by on-disk files. However, our observations revealed that, in mobile devices, file-mapped pages consume significantly more memory than anonymous pages. Last but not least, most of the current compressed swap schemes blindly follow the least-recently-used (LRU) discipline when choosing the victim pages for replacement, not considering the compression ratio or data density of the cached pages. To overcome the aforementioned problems and maximize the memory efficiency, we propose a compressed swap scheme, called enhanced zswap (ezswap), for mobile devices. ezswap accommodates not only anonymous pages, but also clean file-mapped pages. It estimates the compression ratio of incoming pages with their information entropy, and selectively compresses and caches the pages only with beneficial compression ratios. In addition, its admission control and cache replacement algorithms are based on a costbenefit model that considers not only the access recency of cached pages but also their information density and expected eviction cost. The proposed scheme was implemented in the Linux kernel for Android. Our evaluation with a series of commercial applications demonstrated that it reduced the amount of flash memory read by up to 55%, thereby improving the application launch time by up to 22% in comparison to the original zswap.

show abstract

Section: B Swap Schemes For Mobile Devicesmentioning

confidence: 99%

$ezswap$ : Enhanced Compressed Swap Scheme for Mobile Devices

Kim

Seo

2019

IEEE Access

View full text Add to dashboard Cite

show abstract

“…The swap in/out mechanism [14] is widely used to run applications that require larger memory than the physical memory capacity. Unfortunately, most of the mobile device manufacturers do not use the swap in/out mechanism [15]- [17]. Because swapping operations work with a slow storage device with limited endurance, they fail to provide reasonably predictable performance [18]- [20].…”

Section: A Conventional Memory Managementmentioning

confidence: 99%

Virtual memory partitioning for enhancing application performance in mobile platforms

Lim

Min

Eom

2013

IEEE Trans. Consumer Electron.

View full text Add to dashboard Cite

Recently, the amount of running software on smart mobile devices is gradually increasing due to the introduction of application stores. The application store is a type of digital distribution platform for application software, which is provided as a component of an operating system on a smartphone or tablet. Mobile devices have limited memory capacity and, unlike server and desktop systems, due to their mobility they do not have a memory slot that can expand the memory capacity. Low memory killer (LMK) and out-ofmemory killer (OOMK) are widely used memory management solutions in mobile systems. They forcibly terminate applications when the available physical memory becomes insufficient. In addition, before the forced termination, the memory shortage incurs thrashing and fragmentation, thus slowing down application performance. Although the existing page reclamation mechanism is designed to secure available memory, it could seriously degrade user responsiveness due to the thrashing. Memory management is therefore still important especially in mobile devices with small memory capacity.This paper presents a new memory partitioning technique that resolves the deterioration of the existing application life cycle induced by LMK and OOMK. It provides a completely isolated virtual memory node at the operating system level. Evaluation results demonstrate that the proposed method improves application execution time under memory shortage, compared with methods in previous studies 1 .

show abstract

“…If there are no clean pages in a predefined time window, a standard LRU is used. To further reduce the number of flush memory write, Park, et al [14] proposed to combine the Clean-first-LRU with selective compression.…”

Section: Background and Related Researchmentioning

confidence: 99%

Reducing Energy of DRAM/Flash Memory System by OS-controlled Data Refresh

Moshnyaga

Reinman

et al. 2007

2007 IEEE International Symposium on Circuits and Systems

View full text Add to dashboard Cite

Abstract-This paper presents a new approach to reduce energy consumption of DRAM/flash memory system by lowering the frequency of DRAM refreshes. The approach is based on two ideas: (1) a DRAM based swap-cache that reduces the number of writes to the flash memory by keeping dirty pages as long as possible; and (2) OS-controlled page allocation/aging policy that stops refreshing for banks, whose pages are clean and not accessed for a long time. Simulations show that the approach can reduce the DRAM refresh energy by 59-74% and the overall energy of DRAM/flash memory system by 8-24% without increase in the execution

show abstract

Compressed Swapping for NAND Flash Memory Based Embedded Systems

Cited by 4 publications

References 10 publications

$ezswap$ : Enhanced Compressed Swap Scheme for Mobile Devices

$ezswap$ : Enhanced Compressed Swap Scheme for Mobile Devices

Virtual memory partitioning for enhancing application performance in mobile platforms

Reducing Energy of DRAM/Flash Memory System by OS-controlled Data Refresh

Contact Info

Product

Resources

About