Swap compression: resurrecting old ideas

Cortés, Toni; Becerra, Yolanda; Cervera, Raúl

doi:10.1002/(sici)1097-024x(20000425)30:5<567::aid-spe312>3.3.co;2-q

Cited by 5 publications

(2 citation statements)

References 16 publications

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“…Previous research [18], [19], [20], [21], [22], [23] has also argued that online compression of memory (fixed-size) pages can improve memory performance, while the authors in [24] argue that trends in processor and interconnect speeds will favor the use of compression in various distributed and networked systems, even if compression is performed in software. A survey of data compression algorithms appears in [2].…”

Section: Related Workmentioning

confidence: 99%

ZBD: Using Transparent Compression at the Block Level to Increase Storage Space Efficiency

Makatos

Klonatos

Marazakis

et al. 2010

2010 International Workshop on Storage Network Architecture and Parallel I/Os

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In this work we examine how transparent compression in the I/O path can improve space efficiency for online storage. We extend the block layer with the ability to compress and decompress data as they flow between the file-system and the disk. Achieving transparent compression requires extensive metadata management for dealing with variable block sizes, dynamic block mapping, block allocation, explicit work scheduling and I/O optimizations to mitigate the impact of additional I/Os and compression overheads. Preliminary results show that online transparent compression is a viable option for improving effective storage capacity, it can improve I/O performance by reducing I/O traffic and seek distance, and has a negative impact on performance only when single-thread I/O latency is critical.

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Section: Related Workmentioning

confidence: 99%

ZBD: Using Transparent Compression at the Block Level to Increase Storage Space Efficiency

Makatos

Klonatos

Marazakis

et al. 2010

2010 International Workshop on Storage Network Architecture and Parallel I/Os

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“…Swap compression techniques, presented in Roy et al [2001], Cortes et al [2000], Rizzo [1997], and Yang et al [2006], increase effective memory capacity by compressing infrequently used pages and storing them in a swap area in RAM. However, they still rely on an MMU for decompressing a swapped-out page when the page is accessed again.…”

Section: Related Workmentioning

confidence: 99%

Quasistatic shared libraries and XIP for memory footprint reduction in MMU-less embedded systems

Park

Lee

Kim

et al. 2008

ACM Trans. Embed. Comput. Syst.

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Despite a rapid decrease in the price of solid state memory devices, system memory is still a very precious resource in embedded systems. The use of shared libraries and execution-in-place (XIP) is known to be effective in significantly reducing memory usage. Unfortunately, many resourceconstrained embedded systems lack an MMU, making it extremely difficult to support these techniques. To address this problem, we propose a novel shared library technique called a quasi-static shared library and an XIP, both based on our enhanced position independent code technique. In our quasistatic shared libraries, global symbols are bound to pseudoaddresses at linking time and actual physical addresses are bound at loading time. Unlike conventional shared libraries, they do not require symbol tables that take up valuable memory space and, therefore, allow for expedited address translation at runtime. Our XIP technique is facilitated by our enhanced position independent code where a data section can be arbitrarily located. Both the shared library and XIP techniques are made possible by emulating an MMU's memory mapping feature with a data section base register (DSBR) and a data section base table (DSBT).We have implemented these proposed techniques in a commercial ADSL (Asymmetric Digital Subscriber Line) home network gateway equipped with an MMU-less ARM7TDMI processor core, 2MB flash memory, and 16MB RAM. We measured its memory usage and evaluated its performance overhead by conducting a series of experiments. These experiments clearly demonstrate the effectiveness of our techniques in reducing memory usage. The results are impressive: 35% This article is an extended version of the paper that appeared in • Jiyong Park et al. reduction in flash memory usage when using only the shared library and 30% reduction in RAM usage when using the shared library and XIP together. These results were achieved with only a negligible performance penalty of less than 4%. Even though these techniques were applied to uClinux-based embedded systems, they can be used for any MMU-less real-time operating system.

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