Paratick: Reducing Timer Overhead in Virtual Machines

Stijn Schildermans, Kris Aerts, Jianchen Shan, Xiaoning Ding

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


To this day, efficient timer management is a major challenge in virtualized environments. Contemporary timekeeping techniques in guest kernels frequently interact with timer hardware, which requires continual and costly hypervisor interference. This paper proposes the concept of virtual scheduler ticks, which significantly reduces the need for guests to interact with timer hardware through the use of paravirtualization. Guests no longer program scheduler ticks, but rely on the host to inject its own ticks into vCPUs upon VM entry. We implemented virtual scheduler ticks in Linux/KVM under the name paratick. We present a thorough performance analysis of paratick in the context of hardware-assisted X86 virtualization. Paratick reduces VM exits by up to 80%, enhancing system throughput by up to 125% and execution time by up to 15% for multithreaded applications relying heavily on blocking synchronization. For I/O-intensive applications, these numbers are respectively 45%, 30% and 25%.

Original languageEnglish (US)
Title of host publication50th International Conference on Parallel Processing, ICPP 2021 - Main Conference Proceedings
PublisherAssociation for Computing Machinery
ISBN (Electronic)9781450390682
StatePublished - Aug 9 2021
Event50th International Conference on Parallel Processing, ICPP 2021 - Virtual, Online, United States
Duration: Aug 9 2021Aug 12 2021

Publication series

NameACM International Conference Proceeding Series


Conference50th International Conference on Parallel Processing, ICPP 2021
Country/TerritoryUnited States
CityVirtual, Online

All Science Journal Classification (ASJC) codes

  • Software
  • Human-Computer Interaction
  • Computer Vision and Pattern Recognition
  • Computer Networks and Communications


  • I/O
  • multithreading
  • tick
  • timer
  • virtualization


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