NEW! APML Library (E-SMI OOB library) 2.0 is now available                   User Guide

The APML (Advanced Platform Management Link) (Formerly called EPYC™ System Management Interface Out-of-band) Library, is a C-library based on new apml modules (apml_sbrmi and apml_sbtsi) for BMCs running Linux distributions communicating to the processor socket using I2C/I3C bus. APML (E-SMI OOB) library provides APIs for Out-of-band user space software to monitor and control the CPU’s power, energy, performance, and other system management functionality.

Highlights of major release v2.0

  • E-SMI OOB Library and tool has been renamed to APML Library and apml_tool
  • Depends on new apml modules (apml_sbrmi and apml_sbtsi)
  • Supports APML interface over I3C and I2C busses
  • Support system management features introduced in Family 19h Model 10~1Fh, prominent features below
  • DIMM statistics
  • IO and xGMI links Bandwidth
  • Monitor socket and core frequency limits
  • Configure power efficiency modes, df pstate range etc
  • Updated apml_tool with more options, improved the console output for readability

Highlights of release v1.0

APIs to Monitor and control the following feature

  • Power
    1. Get current power consumed
    2. Get and set cap/limit
    3. Get max power cap/limit
  • Performance
    1. Get/Set APML boost limit
    2. Get DDR bandwidth
    3. Set DRAM throttle
    4. C0 residency
  • Temperature
    1. Get CPU temperature
    2. Set High/Low temperature threshold
    3. Set Temp offset
    4. Set alert threshold sample & alert config
    5. Set readorder
  • Single command to create doxygen based PDF document



Target released for AMD EPYC™ server line of CPUs

  • Family 17h, models 0h-Fh and 30h-3Fh.
  • Family 19h, models 0h-Fh, 10h-1Fh and 30h-3Fh.

Operating Systems

AMD APML Suite components are tested on following distributions

  • OpenBMC (Linux) OS


Linux kernel: APML modules

  • apml_sbrmi
  • apml_sbtsi

Resources and Technical Support



Thank you for using APML Library (E-SMI OOB library). Please use APML Library Support for bug reports, support, and feature requests.

Known Issues