The PDL Packet - Summer 2023 Newsletter
Baleen: ML Admission & Prefetching for Flash Caches
Daniel Lin-Kit Wong, Hao Wu, Carson Molder, Sathya Gunasekar, Jimmy Lu, Snehal Khandkar, Abhinav Sharma, Daniel S. Berger, Nathan Beckmann, Gregory R. Ganger
22nd USENIX Conference on File and Storage Technologies (FAST'24), Feb. 27–29, 2024, Santa Clara, CA.
Flash caches are used to reduce peak backend load for throughput-constrained data center services, reducing the total number of backend servers required. Bulk storage systems are a large-scale example, backed by high-capacity but low-throughput hard disks, and using flash caches to provide a more cost-effective storage layer underlying everything from blobstores to data warehouses. However, flash caches must address the limited write endurance of flash by limiting the long-term average flash write rate to avoid premature wearout. To do so, most flash caches must use admission policies to filter cache insertions and maximize the workload-reduction value of each flash write. The Baleen flash cache uses coordinated ML admission and prefetching to reduce peak backend load. [...more]
SIEVE is Simpler than LRU: An Efficient Turn-Key Eviction Algorithm for Web Caches
Yazhuo Zhang, Juncheng Yang, Yao Yue, Ymir Vigfusson, K. V. Rashmi
21st USENIX Symposium on Networked Systems Design and Implementation (NSDI'24), April 16–18, 2024. Santa Clara, CA.
Caching is an indispensable technique for low-cost and fast data serving. The eviction algorithm, at the heart of a cache, has been primarily designed to maximize efficiency—reducing the cache miss ratio. Many eviction algorithms have been designed in the past decades. However, they all trade off throughput, simplicity, or both for higher efficiency. Such a compromise often hinders adoption in production systems. This work presents SIEVE, an algorithm that is simpler than LRU and provides better than state-of-the-art efficiency and scalability for web cache workloads. [...more]
Dear User-Defined Functions, Inlining isn’t working out so great for us. Let’s try batching to make our relationship work. Sincerely, SQL
Kai Franz, Samuel Arch, Denis Hirn, Torsten Grust, Todd C. Mowry, Andrew Pavlo
Conference on Innovative Data Systems Research (CIDR 2024), Chaminade, CA, USA, January 14-17, 2024
SQL’s user-defined functions (UDFs) allow developers to express complex computation using procedural logic. But UDFs have been the bane of database management systems (DBMSs) for decades because they inhibit optimization opportunities, potentially slowing down queries significantly. In response, batching and inlining techniques have been proposed to enable effective query optimization of UDF calls within SQL. Inlining is now available in a major commercial DBMS. But the trade-offs between both approaches on modern DBMSs remain unclear. [...more]
Memento: Architectural Support for Ephemeral Memory Management in Serverless Environments
Memento: Architectural Support for Ephemeral Memory Management in Serverless Environments
56th Annual IEEE/ACM International Symposium on Microarchitecture. October 2023. Toronto, Canada.
Serverless computing is an increasingly attractive paradigm in the cloud due to its ease of use and fine-grained pay-for-what-you-use billing. However, serverless computing poses new challenges to system design due to its short-lived function execution model. Our detailed analysis reveals that memory management is responsible for a major amount of function execution cycles. This is because functions pay the full critical-path costs of memory management in both userspace and the operating system without the opportunity to amortize these costs over their short lifetimes. [...more]
Congratulations to Nathan Beckmann, who has been named a Sloan Research Fellow of 2024. Among 126 early-career scholars, Nathan represents the most promising scientific researchers working today.
The National Science Foundation (NSF) has awarded ECE Assistant Professor Akshitha Sriraman an NSF Faculty Early Career Development (CAREER) Award, a prestigious five-year grant given to junior faculty for research and education.
Congratulations to Kaiyang Zhao, Dimitrios Skarlatos, and PDL alum Ziqi Wang on winning the Best Paper Award at ISCA '23 this June in Orlando, FL for their paper "Contiguitas: The Pursuit of Physical Memory Contiguity in Datacenters" ...