Unblinding the OS to Optimize User-Perceived Flash SSD Latency
نویسندگان
چکیده
In this paper, we present a flash solid-state drive (SSD) optimization that provides hints of SSD internal behaviors, such as device I/O time and buffer activities, to the OS in order to mitigate the impact of I/O completion scheduling delays. The hints enable the OS to make reliable latency predictions of each I/O request so that the OS can make accurate scheduling decisions when to yield or block (busy wait) the CPU, ultimately improving user-perceived I/O performance. This was achieved by implementing latency predictors supported with an SSD I/O behavior tracker within the SSD that tracks I/O behavior at the level of internal resources, such as DRAM buffers or NAND chips. Evaluations with an SSD prototype based on a Xilinx Zynq-7000 FPGA and MLC flash chips showed that our optimizations enabled the OS to mask the scheduling delays without severely impacting system parallelism compared to prior I/O completion methods.
منابع مشابه
Reducing SSD read latency via NAND flash program and erase suspension
In NAND flash memory, once a page program or block erase (P/E) command is issued to a NAND flash chip, the subsequent read requests have to wait until the timeconsuming P/E operation to complete. Preliminary results show that the lengthy P/E operations may increase the read latency by 2x on average. As NAND flashbased SSDs enter the enterprise server storage, this increased read latency caused ...
متن کاملGetting real: lessons in transitioning research simulations into hardware systems
Flash-based solid-state drives have revolutionized storage with their high performance. Their sophisticated internal mechanisms have led to a plethora of research on how to optimize applications, file systems, and internal SSD designs. Due to the closed nature of commercial devices though, most research on the internals of an SSD, such as enhanced flash-translation layers, is performed using si...
متن کاملSolid-State Disk with Double Data Rate DRAM Interface for High-Performance PCs
We propose a Solid-State Disk (SSD) with a Double Data Rate (DDR) DRAM interface for high-performance PCs. Traditional SSDs simply inherit the interface protocol of Hard Disk Drives (HDD) such as Parallel Advanced Technology Attachment (PATA) or Serial-ATA (SATA) for maintaining the compatibility. However, SSD itself provides much higher performance than HDD, hence the interface also needs to b...
متن کاملBandwidth and Delay Optimization by Integrating of Software Trust Estimator with Multi-User Cloud Resource Competence
Trust Establishment is one of the significant resources to enhance the scalability and reliability of resources in the cloud environment. To establish a novel trust model on SaaS (Software as a Service) cloud resources and to optimize the resource utilization of multiple user requests, an integrated software trust estimator with multi-user resource competence (IST-MRC) optimization mechanism is...
متن کاملSchemes for Extending the Lifetime of SSD
The limited use lifetime is a significant drawback of the solid state disk (SSD). When the P/E cycles exceed the nominal endurance limit, the entire SSD is rendered non-functional as worn out. As the low endurance, the MLC Flash based SSD is not suitable used in lifetime-aware applications and the totalbyte-written of conventional MLC SSD is much less than SLC SSD. In this paper, we proposed an...
متن کامل