DAMON: Data Access MONitor

DAMON is a data access monitoring framework subsystem for the Linux kernel. The core mechanisms of DAMON (refer to Design for the detail) make it

• accurate (the monitoring output is useful enough for DRAM level memory management; It might not appropriate for CPU Cache levels, though),
• light-weight (the monitoring overhead is low enough to be applied online), and
• scalable (the upper-bound of the overhead is in constant range regardless of the size of target workloads).

Using this framework, therefore, the kernel’s memory management mechanisms can make advanced decisions. Experimental memory management optimization works that incurring high data accesses monitoring overhead could implemented again. In user space, meanwhile, users who have some special workloads can write personalized applications for better understanding and optimizations of their workloads and systems.

• Frequently Asked Questions
  • Why a new subsystem, instead of extending perf or other user space tools?
  • Can ‘idle pages tracking’ or ‘perf mem’ substitute DAMON?
  • Does DAMON support virtual memory only?
  • Can I simply monitor page granularity?
• Design
  • Configurable Layers
  • Reference Implementations of Address Space Specific Monitoring Operations
  • Address Space Independent Core Mechanisms
• API Reference
  • Structures
  • Functions