Prof. Dr. Frank Bellosa
Yussuf Khalil

Abstract
Suspend is an important mechanism to reduce the power consumption of an unused computer system, at the cost of some latency for returning to the working state. The ACPI specification defines several low-power system states such as suspend-to-RAM (S3) and suspend-to-disk (S4), but these compromise either on the power reduction (S3) or wake latency (S4) aspects. In this thesis, we present a novel mode of system suspend based on S3, but using persistent memory to store the working context, called suspend-to-PMem. In contrast to S3, which has to supply uninterrupted power to DRAM, suspend-to-PMem is able to completely power off all devices. We implement our design entirely within the system firmware, using an FPGA-based PCI Express device to improve compatibility between PMem and commodity hardware. We show that our implementation has a lower overall energy consumption than S3 after only one hour in suspend. The wake latency is increased by up to 9 times compared to S3 mainly due to the FPGA’s initialization time.

BibTex:

@bacholorthesis{meyer23suspend,
  author = {Fabian Meyer},
  title = {Fast and Power-Efficient System
Suspend Using Persistent Memory},
  type = {Bachelor Thesis},
  year = 2023,
  month = oct # "11",
  school = {Operating Systems Group, Karlsruhe Institute of Technology (KIT), Germany}
  }