Memory management

About: Memory management is a research topic. Over the lifetime, 16743 publications have been published within this topic receiving 312028 citations. The topic is also known as: memory allocation.

Fit a compact spread estimator in small high-speed memory

Abstract: The spread of a source host is the number of distinct destinations that it has sent packets to during a measurement period. A spread estimator is a software/hardware module on a router that inspects the arrival packets and estimates the spread of each source. It has important applications in detecting port scans and distributed denial-of-service (DDoS) attacks, measuring the infection rate of a worm, assisting resource allocation in a server farm, determining popular Web contents for caching, to name a few. The main technical challenge is to fit a spread estimator in a fast but small memory (such as SRAM) in order to operate it at the line speed in a high-speed network. In this paper, we design a new spread estimator that delivers good performance in tight memory space where all existing estimators no longer work. The new estimator not only achieves space compactness, but operates more efficiently than the existing ones. Its accuracy and efficiency come from a new method for data storage, called virtual vectors, which allow us to measure and remove the errors in spread estimation. We also propose several ways to enhance the range of spread values that the estimator can measure. We perform extensive experiments on real Internet traces to verify the effectiveness of the new estimator .

SwiftNet: Real-time Video Object Segmentation

Abstract: In this work we present SwiftNet for real-time semisupervised video object segmentation (one-shot VOS), which reports 77.8% $\mathcal{J}\& \mathcal{F}$ and 70 FPS on DAVIS 2017 validation dataset, leading all present solutions in overall accuracy and speed performance. We achieve this by elaborately compressing spatiotemporal redundancy in matching-based VOS via Pixel-Adaptive Memory (PAM). Temporally, PAM adaptively triggers memory updates on frames where objects display noteworthy inter-frame variations. Spatially, PAM selectively performs memory update and match on dynamic pixels while ignoring the static ones, significantly reducing redundant computations wasted on segmentation-irrelevant pixels. To promote efficient reference encoding, light-aggregation encoder is also introduced in SwiftNet deploying reversed sub-pixel. We hope SwiftNet could set a strong and efficient baseline for real-time VOS and facilitate its application in mobile vision. The source code of SwiftNet can be found at https://github.com/haochenheheda/SwiftNet.

An Adaptive-Rate Error Correction Scheme for NAND Flash Memory

Abstract: ECC has been widely used to enhance flash memory endurance and reliability. In this work, we propose an adaptive-rate ECC scheme with BCH codes that is implemented on the flash memory controller. With this scheme, flash memory can trade storage space for higher error correction capability to keep it usable even when there is a high noise level.

Virtual memory: issues of implementation

Abstract: Virtual memory was developed to automate the movement of program code and data between main memory and secondary storage to give the appearance of a single large store. This technique greatly simplified the programmer's job, particularly when program code and data exceeded the main memory's size. Virtual memory has now become widely used, and most modern processors have hardware to support it. Unfortunately, there has not been much agreement on the form that this support should take. The result of this lack of agreement is that hardware mechanisms are often completely incompatible. Thus, designers and porters of system level software have two somewhat unattractive choices: they can write software to fit many different architectures or they can insert layers of software to emulate a particular hardware interface. The authors present the software mechanisms of virtual memory from a hardware perspective and then describe several hardware examples and how they support virtual memory software. Their focus is to show the diversity of virtual memory support and, by implication, how this diversity complicates the design and porting of OSs. The authors introduce basic virtual memory technologies and then compare memory management designs in three commercial microarchitectures. They show the diversity of virtual memory support and, by implication, how this diversity can complicate and compromise system operations.