Publications by Willy Zwaenepoel

Hailstorm: Disaggregated Compute and Storage for Distributed LSM-based Databases

Willy Zwaenepoel, Laurent Bindschaedler, Ashvin Goel

Distributed LSM-based databases face throughput and latency issues due to load imbalance across instances and interference from background tasks such as flushing, compaction, and data migration. Hailstorm addresses these problems by deploying the database ...

ACM2020

The Fake News Vaccine

Rachid Guerraoui, Willy Zwaenepoel, Anne-Marie Kermarrec, Alexandre David Olivier Maurer, Matej Pavlovic, Oana Maria Balmau

While spreading fake news is an old phenomenon, today social media enables misinformation to instantaneously reach millions of people. Content-based approaches to detect fake news, typically based on automatic text checking, are limited. It is indeed diffi ...

2019

PaRiS: Causally Consistent Transactions with Non-blocking Reads and Partial Replication

Willy Zwaenepoel, Diego Didona, Kristina Spirovska

Geo-replicated data platforms are the backbone of several large-scale online services. Transactional Causal Consistency (TCC) is an attractive consistency level for building such platforms. TCC avoids many anomalies of eventual consistency, eschews the syn ...

IEEE COMPUTER SOC2019

Distributed Transactional Systems Cannot Be Fast

Rachid Guerraoui, Willy Zwaenepoel, Diego Didona, Junxiong Wang, Panagiota Fatourou

We prove that no fully transactional system can provide fast read transactions (including read-only ones that are considered the most frequent in practice). Specifically, to achieve fast read transactions, the system has to give up support of transactions ...

2019

Drowsy-DC: Data center power management system

Willy Zwaenepoel, Baptiste Joseph Eustache Lepers, Mathieu Paul Fernand Bacou

In a modern data center (DC), a large majority of costs arise from energy consumption. The most popular technique used to mitigate this issue is virtualization and more precisely virtual machine (VM) consolidation. Although consolidation may increase serve ...

IEEE2019

Managing Tail Latency in Datacenter-Scale File Systems Under Production Constraints

Willy Zwaenepoel, Ricardo Bianchini, Maria Fernanda Borge Chavez

Distributed file systems often exhibit high tail latencies, especially in large-scale datacenters and in the presence of competing (and possibly higher priority) workloads. This paper introduces techniques for managing tail latencies in these systems, whil ...

ASSOC COMPUTING MACHINERY2019

Size-aware Sharding For Improving Tail Latencies in In-memory Key-value Stores

Willy Zwaenepoel, Diego Didona

This paper introduces the concept of size-aware sharding to improve tail latencies for in-memory key-value stores, and describes its implementation in the Minos key-value store. ...

USENIX ASSOC2019

PaRiS: Causally Consistent Transactions with Non-blocking Reads and Partial Replication

Willy Zwaenepoel, Diego Didona, Kristina Spirovska

Geo-replicated data platforms are at the backbone of several large-scale online services. Transactional Causal Consistency (TCC) is an attractive consistency level for building such platforms. TCC avoids many anomalies of eventual consistency, eschews the ...

2019

The Battle of the Schedulers: FreeBSD ULE vs. Linux CFS

Willy Zwaenepoel, Baptiste Joseph Eustache Lepers, Sébastien Chevalley, Justinien Gérard Alain Bouron

This paper analyzes the impact on application performance of the design and implementation choices made in two widely used open-source schedulers: ULE, the default FreeBSD scheduler, and CFS, the default Linux scheduler. We compare ULE and CFS in otherwise ...

2018

Low-Overhead Dynamic Instruction Mix Generation using Hybrid Basic Block Profiling

Willy Zwaenepoel, Andrzej Pawel Nowak

Dynamic instruction mixes form an important part of the toolkits of performance tuners, compiler writers, and CPU architects. Instruction mixes are traditionally generated using software instrumentation, an accurate yet slow method, that is normally limite ...

2018