Parallel and Distributed Systems Group

Computer Science Department of Telecom SudParis

New paper “State-Machine Replication for Planet-Scale Systems” to be presented at Eurosys’20

New paper “State-Machine Replication for Planet-Scale Systems” to be presented at Eurosys’20. Congrat to Pierre and Tuanir!

New paper “Using differential execution analysis to identify thread interference”. To appear in IEEE Transactions on Parallel and Distributed Systems

Abstract Understanding the performance of a multi-threaded application is difficult. The threads interfere when they access the same shared resource, which slows down their execution. Unfortunately, current profiling tools report the hardware components or the synchronization primitives that saturate, but they cannot tell if the saturation is the cause of a performance bottleneck. In this paper, we propose a holistic metric able to pinpoint the blocks of code that suffer interference the most, regardless of the interference cause. Our metric uses performance variation as a universal indicator of interference problems. With an evaluation of 27 applications we show that our metric can identify interference problems caused by 6 different kinds of interference in 9 applications. We are able to easily remove 7 of the bottlenecks, which leads to a performance improvement of up to 9 times

New paper “ScalOMP: analyzing the Scalability of OpenMP applications” to be presented at IWOMP’19

Anton Daumen will present his work “ScalOMP: analyzing the Scalability of OpenMP applications” at IWOMP’19. 

His paper is available online:

Abstract : Achieving good scalability from parallel codes is becoming increasingly difficult due to the hardware becoming more and more complex. Performance tools help developers but their use is sometimes complicated and very iterative. In this paper we propose a simple methodology for assessing the scalability and for detecting performance problems in an OpenMP application. This methodology is implemented in a performance analysis tool named ScalOMP that relies on the capabilities of OMPT for analyzing OpenMP applications. ScalOMP reports the code regions with scalability issues and suggests optimization strategies for those issues. The evaluation shows that ScalOMP incurs low overhead and that its suggestions lead to significant performance improvement of several OpenMP applications