Making RCU Safe For Battery-powered Devices
Paul E. McKenney, from IBM, shows us how to make RCU safe for battery-powered devices. Making RCU Safe for Battery-Powered Devices Back in the 1990s, energy efficiency was not even on the list of RCU-related concerns. Systems using RCU at that time dealt with either large quantities of heavy equipment or large financial flows, so that the energy consumption of the entire server (let alone RCU's contribution) was way down in the noise. This situation changed dramatically with the 2002 introduction of RCU into the Linux kernel. Since then, RCU's energy-efficiency code has been rewritten more than five times. The most recent rewrite was motivated by workloads where RCU was leaving tens of percent of potential energy savings on the table. This talk will give a brief overview of how energy efficiency came to RCU, the current situation, future prospects, and generally applicable lessons learned. Paul E. McKenney, IBM Paul E. McKenney is a Distinguished Engineer with the IBM Linux Technology Center, where he maintains the RCU implementation within the Linux kernel. He has been coding for almost four decades, and more than half of that on parallel hardware. His prior lives include working on the DYNIX/ptx kernel at Sequent, work on packet radio, Internet protocols, and system administration at SRI International, and work on soft-realtime systems as a self-employed contract programmer. His hobbies include what passes for running at his age along with the usual house-wife-and-kids habit.