In data-intensive applications, such as databases and key-value stores, reducing the request handling latency is important for providing better data services. In such applications, I/O-intensive background tasks, such as checkpointing, are the major culprit in worsening the latency due to the contention in shared I/O stack and storage. To minimize the contention, properly prioritizing I/Os is crucial but the effectiveness of existing approaches is limited for two reasons. First, statically deciding the priority of an I/O is insufficient since high-priority tasks can wait for low-priority I/Os due to I/O priority inversion. Second, multiple independent layers in modern storage stacks are not holistically considered by existing approaches which thereby fail to effectively prioritize I/Os throughout the I/O path. In this paper, we propose a request-centric I/O prioritization that dynamically detects and prioritizes I/Os delaying request handling at all layers in the I/O path. The proposed scheme is implemented on Linux and is evaluated with three applications, PostgreSQL, MongoDB, and Redis. The evaluation results show that our scheme achieves up to 53% better request throughput and 42× better 99th percentile request latency (84 ms vs. 3581 ms), compared to the default configuration in Linux.
|Title of host publication||Proceedings of the 15th USENIX Conference on File and Storage Technologies, FAST 2017|
|Number of pages||14|
|Publication status||Published - 2017|
|Event||15th USENIX Conference on File and Storage Technologies, FAST 2017 - Santa Clara, United States|
Duration: 2017 Feb 27 → 2017 Mar 2
|Name||Proceedings of the 15th USENIX Conference on File and Storage Technologies, FAST 2017|
|Conference||15th USENIX Conference on File and Storage Technologies, FAST 2017|
|Period||17/2/27 → 17/3/2|
Bibliographical noteFunding Information:
We would like to thank the anonymous reviewers and our shepherd, Raju Rangaswami, for their valuable comments. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. NRF-2014R1A2A1A10049626) and by Samsung Electronics.
© Proceedings of the 15th USENIX Conference on File and Storage Technologies, FAST 2017. All rights reserved.
All Science Journal Classification (ASJC) codes
- Hardware and Architecture
- Computer Networks and Communications