Transactions chasing Instruction Locality on multicores

For several decades, online transaction processing (OLTP) has been one ofthe main applications that drive innovations in the data managementecosystem and in turn the database and computer architecture communities.Despite fundamentally novel approaches from industry and various researchproposals from academia, the fact that OLTP workloads cannot properlyexploit the modern micro-architectural features of the commodity hardwarehas not changed for the last 15 years. OLTP wastes more than half of itsexecution cycles to memory stalls and, as a result, OLTP performancedeteriorates and the underlying modern hardware is largely underutilized.In this talk, I initially present the findings of our recent workloadcharacterization studies, which advocate that the large instructionfootprint of the transactions is the dominant factor in the lowutilization of the existing micro-architectural resources. However, theworker threads of an OLTP system usually execute similar transactions inparallel, meaning that threads running on different cores share anon-negligible amount of instructions. Then, I show an automated way toexploit the instruction commonality among transactional threads andminimize instruction misses. By spreading the execution of a transactionover multiple cores in an adaptive way through thread migration, we enableboth an ample L1 instruction cache capacity and re-use of commoninstructions by localizing them to cores as threads migrate.

Curriculum Vitae

Pinar Tozun is a fourth year PhD student at Ecole Polytechnique Federalede Lausanne (EPFL) working under supervision of Prof. Anastasia Ailamakiin Data-Intensive Applications and Systems (DIAS) Laboratory. Her researchfocuses on scalability and efficiency of transaction processing systems onmodern hardware. Pinar interned at University of Twente (Enschede, TheNetherlands) during summer 2008 and Oracle Labs (Redwood Shores, CA)duringSummer 2012. Before starting her PhD, she received her BSc degree inComputer Engineering department of Koc University in 2009 as the topstudent.